Europa
Until we determine that there is no life on Europa I will consider it our best chance of finding life anywherein the universe. In fact if we find no life on Europa, we will get a far deeper view of the possibility of INTELLIGENT DESIGN.
 
 Europa has long been considered by scientists and celebrated in science fiction as one of the handful of places in the Solar System (along with Mars and Saturn's moon Titan) that could possess an environment where primitive forms of life could possibly exist. "We are interested in identifying the time and places on Europa where liquid water might exist. We want to go back to some of these areas that suggest soft ice or liquid water under the ice and test some of the questions we're asking now." The interior characteristics are inferred from gravity field and magnetic field measurements by the Galileo spacecraft. Europa's radius is 1565 km, not too much smaller than our Moon's radius. Europa has a metallic (iron, nickel) core (shown in gray) drawn to the correct relative size. The core is surrounded by a rock shell (shown in brown). The rock layer of Europa (drawn to correct relative scale) is in turn surrounded by a shell of water in ice or liquid form (shown in blue and white and drawn to the correct relative scale). The surface layer of Europa is shown as white to indicate that it may differ from the underlying layers. Galileo images of Europa suggest that a liquid water ocean might now underlie a surface ice layer several to ten kilometers thick. Europa - The Past and Future
This artistic picture represents Europa during the dawn of the Solar System's creation. At this point, in time oceans graced the surface of Europa. Since liquid water existed in the past, could life have formed and even exist today? The primary ingredients for life are water, heat, and organic compounds obtained from comets and meteorites. Europa has had all three. From the images and data collected by the Galileo spacecraft, scientists believe that a subsurface ocean existed in relative recent history and may still be present beneath the icy surface. Europa's water should have frozen long ago, but warming could be occurring due to the tidal tug of war with Jupiter and neighboring moons. The heat from the aging sun should be sufficient to melt the ice and once again produce an ocean.

Ridges on Europa
This view of Europa shows a portion of the surface that has been highly disrupted by fractures and ridges. This picture covers an area about 238 kilometers (150 miles) wide by 225 kilometers (140 miles), or about the distance between Los Angeles and San Diego. Symmetric ridges in the dark bands suggest that the surface crust was separated and filled with darker material, somewhat analogous to spreading centers in the ocean basins of Earth. Although some impact craters are visible, their general absence indicates a youthful surface. The youngest ridges, such as the two features that cross the center of the picture, have central fractures, aligned knobs, and irregular dark patches. These and other features could indicate cryovolcanism, or processes related to eruption of ice and gases.
 This image shows two views of the trailing hemisphere of Europa. The left image shows the approximate natural color appearance of Europa. The image on the right is a false-color composite version combining violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. Dark brown areas represent rocky material derived from the interior, implanted by impact, or from a combination of interior and exterior sources. Bright plains in the polar areas (top and bottom) are shown in tones of blue to distinguish possibly coarse-grained ice (dark blue) from fine-grained ice (light blue). Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. The bright feature containing a central dark spot in the lower third of the image is a young impact crater some 50 kilometers (31 miles) in diameter. This crater has been provisionally named 'Pwyll' for the Celtic god of the underworld. False Color Image of Minos Linea Region
False color has been used here to enhance the visibility of certain features in this composite of three images of the Minos Linea region on Jupiter's moon Europa taken on 28 June 1996 Universal Time by the Galileo spacecraft. Triple bands, lineae and mottled terrains appear in brown and reddish hues, indicating the presence of contaminants in the ice. The icy plains, shown here in bluish hues, subdivide into units with different albedos at infrared wavelengths probably because of differences in the grain size of the ice. The composite was produced using images with effective wavelengths at 989, 757, and 559 nanometers. The spatial resolution in the individual images ranges from 1.6 to 3.3 kilometers (1 to 2 miles) per pixel. The area covered, centered at 45N, 221 W, is about 1,260 km (about 780 miles) across. Near-Infrared Image of Europa on the Galileo spacecraft imaged most of Europa, including the north polar regions, at high spectral resolution at a range of 156,000 km (97,500 miles) during the G1 encounter on June 28 1996. The image on the right shows Europa as seen by NIMS, centered on 25 degrees N latitude, 220 W longitude. This is the hemisphere that always faces away from Jupiter. The image on the left shows the same view point from the Voyager data (from the encounters in 1979 and 1980). The NIMS image is in the 1.5 micron water band, in the infrared part of the spectrum. Comparison of the two images, infrared to visible, shows a marked brightness contrast in the NIMS 1.5 micron water band from area to area on the surface of Europa, demonstrating the sensitivity of NIMS to compositional changes. NIMS spectra show surface compositions ranging from pure water ice to mixtures of water and other minerals which appear bright in the infrared.

Europa's Broken Ice
Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice as thick as 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption.
Europa's Active Surface
A newly discovered impact crater can be seen just right of the center of this image of Jupiter's moon Europa returned by NASA's Galileo spacecraft camera. The crater is about 30 kilometers (18.5 miles) in diameter. The impact excavated into Europa's icy crust, throwing debris (seen as whitish material) across the surrounding terrain. Also visible is a dark band, named Belus Linea, extending east-west across the image. This type of feature, which scientists call a "triple band," is characterized by a bright stripe down the middle. The outer margins of this and other triple bands are diffuse, suggesting that the dark material was put there as a result of possible geyser-like activity which shot gas and rocky debris from Europa's interior. The curving "X" pattern seen in the lower left corner of the image appears to represent fracturing of the icy crust and infilling by slush which froze in place.

Dark Bands on Europa
Dark crisscrossing bands on Jupiter's moon Europa represent widespread disruption from fracturing and the possible eruption of gases and rocky material from the moon's interior in this four-frame mosaic of images from NASA's Galileo spacecraft. These and other features suggest that soft ice or liquid water was present below the ice crust at the time of disruption. The data do not rule out the possibility that such conditions exist on Europa today. The pictures were taken from a distance of 156,000 kilometers (about 96,300 miles) on June 27, 1996. Many of the dark bands are more than 1,600 kilometers (1,000 miles) long, exceeding the length of the San Andreas fault of California. Some of the features seen on the mosaic resulted from meteoritic impact, including a 30-kilometer (18.5 mile) diameter crater visible as a bright scar in the lower third of the picture. In addition, dozens of shallow craters seen in some terrains along the sunset terminator zone (upper right shadowed area of the image) are probably impact craters. Other areas along the terminator lack craters, indicating relatively youthful surfaces, suggestive of recent eruptions of icy slush from the interior. The lower quarter of the mosaic includes highly fractured terrain where the icy crust has been broken into slabs as large as 30 kilometers (18.5 miles) across.

11 dimensional M theory    

gamma ray bursts    blackholes

Reality is non-local communicate faster than light

 by Mike Milne                     

     .                     

 INDEX:

Letters and Introduction…medley of information: poem, aurora, Europa

Black Holes p. 15

Big timeline & Einstein p.21

Holographic principal p. 28

Picture gallery, favorite stars p. 30

Gamma ray bursts p. 34

Dark matter, expansion speed etc. p. 40

Theorys of…. P.

Compiling the latest information on science is an exponentially expanding realm of endeavour. What with 4 dimensional branes out there bumping into each other willy nilly and educators like my high school science teacher who had not read anything since before E= mc 2. He claimed that space was endless which of course it was not! Below is a letter I sent out which shows  how man is so stubborn to change. Change we must as we learn to manipulate quantum effects. My present set of questions remain unanswered #1 if no time at horizon of a black hole, I can’t believe that matter will fall in. time will then be seen to be speeding up, as the universe will come to an end before I enter the event itself. #2 if an event like the big bang was to say happen again at some point within our 3 dimensions when will we find out about it, in other words if it occurred now 1 million light years away would we have to wait to know about it. #3 this brings me to short gamma ray bursts. No-one can say for sure what they are. Brane bumping does it for me! There is an incredibly extreme energy released without logical releasing mechanism nor the matter necessary for such release.

M theory and gamma ray bursts > > Topic: Gamma-ray Bursts > Level: I study astronomy as a hobby, several hours daily, love the awesome > wonder of it all and am very perplexed by FRED's. > > What if, as the Membrane theory is correct, there are continued touches of > these membranes creating these gamma ray bursts, if 11 B light years away > would black holes have evolved enough to be the source We don't know of any proposed explanations of gamma-ray bursts from M theory. In fact, the only prediction we know of about the consequences of two branes touching is to cause the Big Bang, which of course is completely different from gamma-ray bursts: http://news.bbc.co.uk/1/hi/sci/tech/1270726.stm On the other hand, there is a growing body of evidence linking gamma-ray bursts with a certain type of supernova: http://imagine.gsfc.nasa.gov/docs/features/news/26jun03.html So these would be the birth of black holes, the endpoint of evolution for the most massive stars. They consume their nuclear fuel at a furious rate, only lasting about 10 million years. So there is no problem explaining even the most distant gamma-ray bursts this way. Hope this helps, Koji & Scott for "Ask a High Energy Astronomer" As in the big bang when the membranes theoretically touched, suggests that they may touch again, less likely in exactly the same way, thus not necessarily producing the same results….I’m just saying that something awesome is happening here outside of the too weak excuse …black holes. There is roughly one GRB daily somewhere suggests that it is a regular event. Black holes aren’t. mike milne

to S.W.Hawking@damtp.cam.ac.uk

Just wanted to take the time to thank you for all your awesome work in astrophysics.You have given us so much! Loved universe in a nutshell, awesome stuff. Me, I am an armchair astronomy enthusiast and par-time philosopher. Short GRB's are what really turn me on! My home-made theory of the holographic principle's 5th dimension somehow interfering has been confirmed  by some to possibly rationalize the short GRB's. Any comment would be golden to me. I have some of your lectures on my website (Visitors can find it at this location (URL): http://quanta-m.tripod.com/ ), and do not make $ on it as per your request, unless someone would bet ME a pound that you won't write back.               with deep respect

                                    Mike Milne

Your email regarding "thanks" has been received.
Professor Hawking very much regrets that due to the severe limitations he works under, and the huge amount of mail he receives, he may not have time to write you a reply.  All e-mail is read.  We have NO facilities in our department to deal with specific scientific enquiries, or theories. Please see the website http://www.hawking.org.uk for more informationabout Professor Hawking, his life and his work. Yours faithfully David Pond Graduate Assistant toProfessor S W Hawking CH CBE FRS Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, CB3 0WA.United Kingdom

An unknown bright star dimmed from bright to invisible in a matter of seconds last night in a clear dark sky N of Brampton Ont. Can. (18/05/06 @ 955pm)
I was naked eye observing Th evening as usual and just NW of Ursa Major at about 10 o'clock high, I noticed a bright star that I did not recognize that was possibly in or near Lynx. from my location @ L43°42'N -79°24'W . Can anyone identify this phenomenon?

Man in general seems to yearn for some kind of "GOD CONTACT". Why is this? I believe this inate desire comes from the fact that God does in deed exist. It is interesting astronomically that the Bible predicts an end of the universe...long before man even knew there was a universe! It also states that death is merely a transition into something greater than mere life. This got me wondering about cosmology's search for thye equation that will sum up everything we know. I believe philosophy and the Bible will aid in finding this solution.

For instance one big scientific problem, that of the missing mass(93%) of our galaxy is black holes or some other exotic energy/matter yet unknown...unexpected clue of hot X-ray emitting gas was recently been detected escaping

 is easily understood by T> L & T> U where T is Totality and L is Life, U is the Universe

stardust@jpl.nasa.gov

I am so eager to hear any news on stardust findings, you publish how so many are working so hard on the samples, yet no word at all on what these samples are made of. Surely this is obviously axiously awaited and easy enough to access. One of my greatest hurdles and beefs, is getting updates on info all over Nasa and JPL sites...lots of stuff has not been altered or updated in years....Please let us know!!!

thanks Mike

Feb. 6th 2006

Since the Sample Canister has been delivered to the STARDUST cleanroom at Johnson Space Center (JSC) on January 17th, the Preliminary Examination Team (PET) along with JSC Curatorial staff have been making good progress toward processing the returned samples. Everything has proceeded smoothly; in fact, we are ahead of our planned schedule on several fronts. The Principal Investigator, Deputy Principal Investigator and several subteam leads have worked 8:00 am until near midnight for the last two days. We have removed many aerogel fragments and found many particles in them; removed 7 pieces of aluminum foil and found very many small craters in them; removed several particles from the fragments and examined them by IR; microtomed several particles; removed two Wild 2 aerogel cells from the tray; and sliced one of the removed aerogel cell with the harmonic saw. Sometimes we have up to 7 teams working in parallel each day; several of the the PET members have worked from 8:00 am till near midnight in the last two days. Prepared samples will be distributed to PET subteam members today.

The short-hard
                                    gamma-ray bursts are indeed unusual and fascinating events.  They have been known
                                    for many years but we still know very little about them.  At present the leading
                                    theories are that they are due to explosions on the surfaces of highly magnetized neutron stars(which are also known as magnetars)
                                    or that they are due to merging compact objects such as neutron stars, white dwarfs, or black holes.Both of these theories
                                    have problems and the solution to the mystery

of the short-hard gamma-ray bursts will probably have to wait until we have collect a lot more data on them.

Some scientists have speculated that the short-hard gamma-ray 

bursts may be caused by some sort of effect due to higher dimensions or interactions
                                    between branes, but there is no evidence to support these idea.  Still, it is
                                    an interesting possibility. At present there is no e-mail list for Swift or for reports on new theories regarding gamma-ray
                                    bursts.  Web sites such as<http://www.space.com/> are good places to look for up-to-date information about space and astrophysics. 
                                    If you are interested in more technicalinformation look at the Gamma-Ray Burst Coordinates Network(http://gcn.gsfc.nasa.gov/), but please be aware that this information is aimed at professional astrophysicists, not at the general public.

stephen holland Swift Science Centre From: spacermike00@yahoo.ca To: swifthelp@olegacy.gsfc.nasa.gov

 Subject: [Swift #413] short grb's
                                    I am awed by short grb's, I even like that no-one can positively identify their source, which tends to make them even more
                                    mysterious. With limited knowledge of M theory and the holographic principle, but with lots of imagination, I wonder if theories
                                    not mentioned by Mr. Hawkings et al could include: membrane activity, or extra-dimensional interference. Merging black holes
                                    (as suggested by some) on a daily basis just doesn't seem like a reasonable scenario. I was hoping you could keep me on an
                                    email list for reports as they become available. thanks mike

In the 1500's Mr. L. of Vinci calculated the earth shadow effect on the moon. Our next generation of astronauts will maybe, on a late-night stroll behind the moon base outpost; guided by the soft light of Earthshine, bend over and scratch something in the moondust: "Leonardo was here."

 In spring 1006 A.D., medieval people living sufficiently south were surprised by the brightest "new star" ever recorded in historic times. Although its exact position could only be figured out recently by finding its nebulous remnant, it was recorded by observers (often astrologers) in Europe, China, Japan, Egypt and Iraq, to have occurred near the star Beta Lupi, on the border to Centaurus. Chinese astrologers apparently has trouble in finding its "omen category", according to Burnham. The supernova was probably seen first on April 30, 1006, according to records from the Far East (China and Japan). It was of apparently yellow color. It was visible for over a year, which indicates that the supernova was probably of type II. Dickel & Milne 1976, SN 1006: Supernova Remnant in X-Rays

Composite Crab The Crab Pulsar, a city-sized, magnetized neutron star spinning 30 times a second, lies at the center of this composite image of the inner region of the well-known Crab Nebula. The spectacular picture combines optical data (red) from the Hubble Space Telescope and x-ray images (blue) from the Chandra Observatory, also used in the popular Crab Pulsar movies. Like a cosmic dynamo the pulsar powers the x-ray and optical emission from the nebula, accelerating charged particles and producing the eerie, glowing x-ray jets. Ring-like structures are x-ray emitting regions where the high energy particles slam into the nebular material. The innermost ring is about a light-year across. With more mass than the Sun and the density of an atomic nucleus, the spinning pulsar is the collapsed core of a massive star that exploded, while the nebula is the expanding remnant of the star's outer layers. The supernova explosion was witnessed in the year 1054 On July 4, 1054 A.D., Chinese astronomers noted a "guest star" in the constellation Taurus; Simon Mitton lists 5 independent preserved Far-East records of this event (one of 75 authentic guest stars - novae and supernovae, excluding comets - systematically recorded by Chinese astronomers between 532 B.C. and 1064 A.D., according to Simon Mitton). This star became about 4 times brighter than Venus in its brightest light, or about mag -6, and was visible in daylight for 23 days...others..

2241 BC ??       ?       -10                Dubiously listed in some source 352 BC ? Chinese; "first such record" according to Hellemans/Bunch
185 AD         Cen       -2     SNR 185    Chinese
369 ?                                      Chinese
386 ?                                      Chinese
393/396        Sco       -3     SNR 393    Chinese
437 ?          Gem
827 ?          Sco/Oph  -10
902 ?          Cas        0
1006    Apr 30  Lup       -9+1  SNR 1006   Arabic; also Chinese, Japanese, European
1054    Jul  4  Tau       -6     M1         Chinese, North American (?); also Arab, Japan
1181    Aug  6  Cas       -1     3C 58      Chinese and Japanese
1203 ?          Sco        0
1230 ?          Aql
1572    Nov  6  Cas       -4     Tycho SNR  Tycho Brahe's SN
1604    Oct  9  Oph       -3     Kepler SNR Johannes Kepler's SN
1680? 1667?     Cas      Cas A      Flamsteed ? not seen ?

 The shapes of planetary nebula like the Helix are important because they likely hold clues to how stars like the Sun end their lives. Recent observations by the orbiting Hubble Space Telescope and the 4-meter Blanco Telescope in Chile, however, have shown the Helix is not really a simple helix. Rather, it incorporates two nearly perpendicular disks as well as arcs, shocks, and even features not well understood. Even so, many strikingly geometric symmetries remain. How a single Sun-like star created such beautiful yet geometric complexity is a topic of research

I watched Venus (near center), joined by Mercury (below) and Saturn (left) in late June 2005 swiftly, silently slip into the sunset. I wondered of and marvelled at the men of olden days who figured out their movements.  

 A POEM BY MIKE MILNE

                 I sat in a field and watched.

                   As Venus swayed with Mercury  

                       Sasheed  Saturn

                      in late June 2005's night sky 

                       swiftly, silently slipping into the sunset. 

                        I wondered of and marvelled at

                          the men who anciently figured out their complex cosmic dances.

5 of the 61 moons in the solar system have an atmosphere (the others being Io, Ganymede, Titan, Triton and Callisto).

An extraterrestrial liquid ocean holds out the tantalizing possibility of life.

Over the last 3 years I have studied cosmolgy with a 'who are we, where are we headed' view. One of my big questions is 'are we alone'  when answered will have a profound significance on the final equation. Europa has been at least the local choice for my speculation. I have tried to locate your thesis paper without success. Is it available to the public? One of the things I love is the ease with which most astronomers share information. Hope you can accomodate me.

      Finally another concern of mine is if we do find other life are we prepared with protocols, or will we try to dominate/exploit them as we have with life forms here on earth. I have found no references to this question yet.

                                   Mike

jwaldie@melbpc.org.au

.  . .When on January 8th, led by some fatality, I turned again to look at the same part of the heavens, I found a very different state of things, for there were three little stars all west of Jupiter, and nearer together than on the previous night."

Galileo Galilei (1564-1642) was one of the greatest mathematicians and astronomers of all time. Born in Pisa on February 15, 1564, his work radically altered the scientific landscape of his time, setting the stage for much of modern science Galileo determined that what he was observing were not stars, but planetary bodies that were in orbit around Jupiter. This discovery provided evidence in support of the Copernican system and showed that everything did not revolve around the Earth.

Aurora from Space

Our sun is an ordinary star, average in size and brightness, compared to the millions of others in the universe. But when energy from the sun travels through 93 million miles of space in only eight minutes to reach us here on Earth, extraordinary things can and do happen.

During fusion, a tiny amount of mass is lost. One helium atom weighs just a little bit less than two hydrogen atoms. That little bit of mass is transformed into an enormous amount of energy, mainly infrared and visible light, which radiates in all directions through space.

http://www.californiasolarcenter.org/events.html

Time and space, according to Einstein's theories of relativity, are woven together, forming a four-dimensional fabric called "space-time." The tremendous mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline. Gravity, says Einstein, is simply the motion of objects following the curvaceous lines of the dimple.If Earth were stationary, that would be the end of the story. But Earth is not stationary. Our planet spins, and the spin should twist the dimple, slightly, pulling it around into a 4-dimensional swirl.   Where did the gold in your jewelry originate? No one is completely sure. The relative average abundance in our Solar System appears higher than can be made in the early universe, in stars, and even in typical supernova explosions. Some astronomers now suggest that neutron-rich heavy elements such as gold might be most easily made in rare neutron-rich explosions such as the collision of neutron stars. In this case, the subject is one of the most famous constellations in the night sky, Crux, the Southern Cross. Gacrux or gamma Crucis is the bright red giant star only 88 light-years distant that forms the top of the Cross seen here near top center. Acrux, the hot blue star at the bottom of the Cross is about 320 light-years distant. Actually a binary star system, Acrux is the alpha star of the compact Southern Cross and lies along a line pointing from Gacrux to the South Celestial Pole, off the lower right edge of the picture. The top of the cross is marked by the lovely pale red star Gamma Crucis, which is in fact a red giant star about 120 light-years distant. Stars of the grand constellation Centaurus almost engulf the Southern Cross with blue giant Beta Centauri, and yellowish Alpha Centauri, appearing as the brightest stars to the left of Gamma Crucis. At a distance of 4.3 light-years, Alpha Centauri, the closest star to the Sun, is actually a triple star system which includes a star similar to the Sun. The Earth's magnetic field which deflects compass needles is measured to be about 1 Gauss, while the strongest fields sustainable in earthbound laboratories are about 100,000 Gauss. A magnetar's monster magnetic field is estimated to be as high as 1,000,000,000,000,000 Gauss. A magnet this strong, located at about half the distance to the Moon would easily erase your credit cards and suck pens out of your pocket.

short GRBs.

Solar-B -- an international mission to study the sun -- launched Friday, Sept. 22 at 4:36 p.m. CDT from Japan. The launch vehicle flew smoothly, and mission controllers have confirmed the satellite's successful placement into its scheduled orbit. In orbit, Solar-B's newly given nickname is "Hinode" -- or sunrise. Led by the Japan Aerospace Exploration Agency, Solar-B is collaboration among the space agencies of Japan, the United States, United Kingdom and Europe. The Marshall Center managed the development of the scientific instrumentation provided by NASA, with additional support by academia and industry.  
 "While the heliosheath protects us from deep-space cosmic rays, at the same time it is busy producing some cosmic rays of its own. A shock wave at the inner boundary of the heliosheath imparts energy to subatomic particles which zip, cosmic-ray-like, into the inner solar system. "We call them 'anomalous cosmic rays.' They're not as dangerous as galactic cosmic rays because they are not so energetic." On the sun, coronal mass ejections occur when solar magnetic field lines snake around each other, forming the letter "S". Usually, they go past each other. But if they connect, it's like a short circuit. The mid-section breaks loose and drives out a coronal mass ejection. 

Right: A schematic diagram of the sun's heliosphere. Anomalous cosmic rays are supposed to come from the Termination Shock--but Voyager 1 found otherwise. Researchers expected Voyager 1 to encounter the greatest number of anomalous cosmic rays at the inner boundary of the heliosheath "because that's where we thought anomalous cosmic rays were produced." Surprise: Voyager crossed the boundary in December 2004 and there was no spike in cosmic rays. Only now, 300+ million miles later, is the intensity beginning to grow."This is really puzzling," says Stone. "Where are these anomalous cosmic rays coming from?"Voyager 1 may find the source--and who knows what else?--as it continues its journey. The heliosheath is 3 to 4 billion miles in thickness, and Voyager 1 will be inside it for another 10 years or so. That's a lot of new territory to explore and plenty of time for more surprises. Image above: Safely back on Earth, the STS-115 crew poses at the Shuttle Landing Facility in front of Atlantis, the orbiter that carried them on their 12-day mission to the International Space Station

McMurdo Panorama from Mars

 the familar constellation Orion. An Orion Deep Field Adrift 1,500 light-years away in one of the night sky's most recognizable constellations, the glowing Orion Nebula and the dark Horsehead Nebula are contrasting cosmic vistas. They both appear in this stunning composite digital image assembled from over 20 hours of data that includes exposures filtered to record emission from hydrogen atoms. The view reveals extensive nebulosities associated with the giant Orion Molecular Cloud complex, itself hundreds of light-years across. The magnificent emission region, the Orion Nebula (aka M42), lies at the upper right of the picture. Immediately to its left are a cluster of of prominent bluish reflection nebulae sometimes called the Running Man. The Horsehead nebula appears as a dark cloud, a small silhouette notched against the long red glow at the lower left. Alnitak is the easternmost star in Orion's belt and is seen as the brightest star to the left of the Horsehead. Below Alnitak is the Flame Nebula, with clouds of bright emission and dramatic dark dust lanes. Fainter tendrils of glowing hydrogen gas are easily traced throughout the region in this Orion deep field.

Come celebrate our universe from Branes to Bangs.... but where to start? I know, lets describe the

Anatomy of a Black Hole... Hubble has shown that hidden at the center of this galaxy are what seem to be disks of matter spiraling into a black hole with a billion times the mass of the Sun! Centaurus A itself is apparently the result of a collision of two galaxies and the left over debris is steadily being consumed by the black hole.                            

The destiny of all matter that falls into a black hole is to get crushed to a point of zero volume and infinite density—a singularity. General relativity also implies that our expanding universe began from a singularity

By definition a black hole is a region where matter collapses to infinite density, and where, as a result, the curvature of spacetime is extreme. Moreover, the intense gravitational field of the black hole prevents any light or other electromagnetic radiation from escaping. But where lies the "point of no return" at which any matter or energy is doomed to disappear from the visible universe? Now brace yourself! Imagine that you are venturing into the black hole yourself. As you travel toward it you may notice nothing out of the ordinary, except an inability to steer yourself in any but one direction -- which is toward the "invisible" hole. You would never know when you had crossed the event horizon were it not for the increased gravitational tugging that draws your body longer and longer, squeezing in from the sides. You wouldn't last long, which is too bad, because theorists believe that inside a black hole, time and space are scrambled up strangely, such that even time travel, or travel to different universes via so-called "wormholes" might become possible

The Event Horizon

Applying the Einstein Field Equations to collapsing stars, German astrophysicist Kurt Schwarzschild deduced the critical radius for a given mass at which matter would collapse into an infinitely dense state known as a singularity. For a black hole whose mass equals 10 suns, this radius is about 30 kilometers or 19 miles, which translates into a critical circumference of 189 kilometers or 118 miles. Schwarzschild Black Hole
If you envision the simplest three-dimensional geometry for a black hole, that is a sphere (known as a Schwarzschild black hole), the black hole's surface is known as the event horizon. Behind this horizon, the inward pull of gravity is overwhelming and no information about the black hole's interior can escape to the outer universe.
Apparent versus Event Horizon

As a doomed star reaches its critical circumference, an "apparent" event horizon forms suddenly. Why "apparent?" Because it separates light rays that are trapped inside a black hole from those that can move away from it. However, some light rays that are moving away at a given instant of time may find themselves trapped later if more matter or energy falls into the black hole, increasing its gravitational pull. The event horizon is traced out by "critical" light rays that will never escape or fall in. Apparent versus Event Horizon

Even before the star meets its final doom, the event horizon forms at the center, balloons out and breaks through the star's surface at the very moment it shrinks through the critical circumference. At this point in time, the apparent and event horizons merge as one: the horizon. For more details, see the caption for the above diagram. The distinction between apparent horizon and event horizon may seem subtle, even obscure. Nevertheless the difference becomes important in computer simulations of how black holes form and evolve. Beyond the event horizon, nothing, not even light, can escape. So the event horizon acts as a kind of "surface" or "skin" beyond which we can venture but cannot see. Imagine what happens as you approach the horizon, then cross the threshold.

: What do you call a group of black holes

... a flock, a brace, a swarm? Monitoring a region around the center of our Galaxy, astronomers have indeed found evidence for a surprisingly large number of variable x-ray sources - likely black holes or neutron stars in binary star systems - swarming around the Milky Way's own central supermassive black hole. Chandra Observatory combined x-ray image data from their monitoring program is shown above, with four variable sources circled and labeled A-D. While four sources may not make a swarm, these all lie within only three light-years of the central supermassive black hole known as Sgr A* (the bright source just above C). Their detection implies that a much larger concentration of black hole systems is present. Repeated gravitational interactions with other stars are thought to cause the black hole systems to spiral inward toward the Galactic Center region.

From supercomputer simulations performed at NCSA and other advanced computational facilities, relativity researchers expect different types of cosmic events to possess characteristic gravitational wave signatures.

Consider the waves emitted by a single, distorted black hole, for example.

Distorted Black Hole

The remarkable thing about a black hole when simulated on a computer is that no matter how it forms or is perturbed, whether by infalling matter, by gravitional waves, or via a collision with another object (including a second black hole), it will "ring" with a unique frequency known as its natural mode of vibration. It's this unique wave signature that will allow scientists to know if they've really detected a black hole. But that's not all. The signal will tell them how big the black hole is and how fast it's spinning.

Care to take a one-way trip into a black hole? The Singularity At the center of a black hole lies the singularity, where matter is crushed to infinite density, the pull of gravity is infinitely strong, and spacetime has infinite curvature. Here it's no longer meaningful to speak of space and time, much less spacetime. Jumbled up at the singularity, space and time cease to exist as we know them. This is a deep X-ray Chandra image of the Lockman Hole, a patch of sky that avoids most of the X-ray absorbing gas of the Milky Way. By combining this image with the Chandra Deep Fields, astronomers have been able to construct the most complete black hole census to date of the Universe. Virtually each of these dots - with the red objects usually cooler than the blue objects - represents a supermassive black hole.

Tuning in to the center of our Milky Way galaxy, radio astronomers explore a complex, mysterious place. A premier high resolution view, this startlingly beautiful picture covers a 4x4 degree region around the galactic center. It was constructed from 1 meter wavelength radio data obtained by telescopes of the Very Large Array near Socorro, New Mexico, USA. The galactic center itself is at the edge of the extremely bright object labeled Sagittarius (Sgr) A, suspected of harboring a million solar mass black hole. Along the galactic plane which runs diagonally through the image are tortured clouds of gas energized by hot stars and bubble-shaped supernova remnants (SNRs) - hallmarks of a violent and energetic cosmic environment. But perhaps most intriguing are the arcs, threads, and filaments which abound in the scene. Their uncertain origins challenge present theories of the dynamics of the galactic center.

Wind from a Black Hole Binary star system GRO J1655-40 consists of a relatively normal star about twice as massive as the Sun co-orbiting with a black hole of about seven solar masses. This striking artist's vision of the exotic binary system helps visualize matter drawn from the normal star by gravity and swirling toward the black hole. But it also includes a wind of material escaping from the black hole's accretion disk. In fact, astronomers now argue that Chandra Observatory x-ray data indicate a high-speed wind is being driven from this system's disk by magnetic forces. Internal magnetic fields also help drive material in the swirling disk into the black hole itself. If you had x-ray eyes as good as Chandra's, you could find GRO J1655-40 about 11,000 light-years away in the constellation Scorpius.

 GRO J1655 40: Evidence for a Spinning Black Hole
Explanation: In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes. The gas surrounding GRO J1655-40, for example, has been found to display an unusual flickering at a rate of 450 times a second. Given a previous mass estimate for the central object of seven times the mass of our Sun, the rate of the fast flickering can be explained by a black hole that is rotating very rapidly. What physical mechanisms actually cause the flickering -- and a slower quasi-periodic oscillation (QPO) -- in accretion disks surrounding black holes and neutron stars remains a topic of much research.

 - Elliptical Galaxy M87
Explanation: In spiral galaxies, majestic winding arms of young stars and interstellar gas and dust rotate in a flat disk around a bulging galactic nucleus. But elliptical galaxies seem to be simpler. Lacking gas and dust to form new stars, their randomly swarming older stars, give them an ellipsoidal (egg-like) shape. Still, elliptical galaxies can be very large. Over 120,000 light-years in diameter (larger than our own Milky Way), elliptical galaxy M87 is the dominant galaxy at the center of the Virgo Galaxy Cluster, some 50 million light-years away. M87 is likely home to a supermassive black hole responsible for the high-energy jet of particles emerging from the giant galaxy's central region. .

 The Center of Centaurus A : A fantastic jumble of young blue star clusters, gigantic glowing gas clouds, and imposing dark dust lanes surrounds the central region of the active galaxy Centaurus A. This mosaic of Hubble Space Telescope images taken in blue, green, and red light has been processed to present a natural color picture of this cosmic maelstrom. Infrared images from the Hubble have also shown that hidden at the center of this activity are what seem to be disks of matter spiraling into a black hole with a billion times the mass of the Sun! Centaurus A itself is apparently the result of a collision of two galaxies and the left over debris is steadily being consumed by the black hole. Astronomers believe that such black hole central engines generate the radio, X-ray, and gamma-ray energy radiated by Centaurus A and other active galaxies. But for an active galaxy Centaurus A is close, a mere 10 million light-years away, and is a relatively convenient laboratory for exploring these powerful sources of energy.

- Accretion Disk Simulation Don't be fooled by the familiar pattern. The graceful spiral structure seen in this computer visualization does not portray winding spiral arms in a distant galaxy of stars. Instead, the graphic shows spiral shock waves in a three dimensional simulation of an accretion disk -- material swirling onto a compact central object that could represent a white dwarf star, neutron star, or black hole. Such accretion disks power bright x-ray sources within our own galaxy. They form in binary star systems which consist of a donor star (not shown above), supplying the accreting material, and a compact object whose strong gravity ultimately draws the material towards its surface. For known x-ray binary systems the size of the accretion disk itself might fall somewhere between the diameter of the Sun (about 1,400,000 kilometers) and the diameter of the Moon's orbit (800,000 kilometers). One interesting result of the virtual reality astrophysics illustrated here is that the simulated disk develops instabilities which tend to smear out the pronounced spiral shocks.

At the singularity, though, the laws of physics, including General Relativity, break down. Enter the strange world of quantum gravity. In this bizzare realm in which space and time are broken apart, cause and effect cannot be unraveled. Even today, there is no satisfactory theory for what happens at and beyond the singularity.

Cosmic Censorship

It's no surprise that throughout his life Einstein rejected the possibility of singularities. So disturbing were the implications that, by the late 1960s, physicists conjectured that the universe forbade "naked singularities." After all, if a singularity were "naked," it could alter the whole universe unpredictably. All singularities within the universe must therefore be "clothed."

But inside what? The event horizon, of course! Cosmic censorship is thus enforced. Not so, however, for that ultimate cosmic singularity that gave rise to the Big Bang.

Science versus Speculation

We can't see beyond the event horizon. At the singularity, randomness reigns supreme. What, then, can we really "know" about black holes? How can we probe their secrets? The answer in part lies in understanding their evolution

• A non-rotating, spherically symmetric black hole, first postulated by Schwarzschild.
• A rotating, spherical black hole, predicted in 1964 by the New Zealand mathematician Roy Kerr.

These two types of black holes have become known as Schwarzschild and Kerr black holes, respectively. Both types of black holes are "stationary" in that they do not change in time, unless they are disturbed in some way. As such, they are among the simple st objects known in General Relativity. They can be completely described in terms of just 2 numbers: their mass M and their angular momentum J.

Theoretically, black holes may also possess electric charge, Q, but it would quickly attract enough charge of the opposite sign. The net result is that any "realistic" or astrophysical black hole would tend to exhibit zero charge. This simplicity of black holes is summed up in the saying "black holes have no hair," meaning that, apart from its mass and momentum, there is no other characteristic (or "hair") that a black hole can exhibit.

(But things may not be quite so simple. Yes -- you've guessed it -- there's more to this story. To explore it, though, is beyond the scope of this exhibit.)

However, both the Schwarzschild and Kerr black holes represent end states. Their formation may result from various processes, all of them quite complicated. When a "real" black hole forms from, say, the collapse of a very mass ive star, or when a black hole is disturbed by, say, another black hole spiralling into it, the resulting dynamics cause disturbances in spacetime that should lead to the generation of gravitational waves.

By numerically solving the Einstein equations on powerful computers, scientists have been able to simulate the gravitational waves emitted by perturbed or interacting black holes. When visualized in movies generated by advan ced computer graphics, the unfolding wave patterns are not only intriguing but strikingly beautiful.

By emitting gravitational waves, non-stationary black holes lose energy, eventually become stationary and cease to radiate in this manner. In other words, they "decay" into stationary black holes, namely holes that are perfectly spherical or whose rotatio n is perfectly uniform. According to Einstein's Theory of General Relativity, such objects cannot emit gravitational waves.

Constellation-X and The Laser Interferometer Space Antenna (LISA) will use the complementary techniques of X-ray spectroscopy and gravitational waves to study black holes. They will probe space, time, and matter in the extreme environment near black holes and track their evolution with cosmic time. These two facilities will be a major resource for a broad astronomy and physics community. The National Academy of Sciences' decadal survey Astronomy and Astrophysics in the New Millennium developed community consensus on the most important science questions and funding priorities. It recommended both LISA and Constellation-X as high priorities for this decade.

  If the Universe is only …

When talking about the distance of a moving object, we mean the spatial separation NOW, with the positions of both objects specified at the current time. In an expanding Universe this distance NOW is larger than the speed of light times the light travel time due to the increase of separations between objects as the Universe expands. This is not due to any change in the units of space and time, but just caused by things being farther apart now than they used to be.

What is the distance NOW to the most distant thing we can see? Let's take the age of the Universe to be 10 billion years. In that time light travels 10 billion light years, and some people stop here. But the distance has grown since the light traveled. The average time when the light was traveling was 5 billion years ago. For the critical density case, the scale factor for the Universe goes like the 2/3 power of the time since the Big Bang, so the Universe has grown by a factor of 2^2/3 = 1.59 since the midpoint of the light's trip. But the size of the Universe changes continuously, so we should divide the light's trip into short intervals. First take two intervals: 5 billion years at an average time 7.5 billion years after the Big Bang, which gives 5 billion light years that have grown by a factor of 1/(0.75)^2/3 = 1.21, plus another 5 billion light years at an average time 2.5 billion years after the Big Bang, which has grown by a factor of 4^2/3 = 2.52. Thus with 1 interval we got 1.59*10 = 15.9 billion light years, while with two intervals we get 5*(1.21+2.52) = 18.7 billion light years. With 8192 intervals we get 29.3 billion light years. In the limit of very many time intervals we get 30 billion light years. With calculus this whole paragraph reduces to this.

Another way of seeing this is to consider a photon and a galaxy 30 billion light years away from us now, 10 billion years after the Big Bang. The distance of this photon satisfies D = 3ct. If we wait for 0.1 billion years, the Universe will grow by a factor of (10.1/10)^2/3 = 1.0066, so the galaxy will be 1.0066*30 = 30.2 billion light years away. But the light will have traveled 0.1 billion light years further than the galaxy because it moves at the speed of light relative to the matter in its vicinity and will thus be at D = 30.3 billion light years, so D = 3ct is still satisfied.

If the Universe does not have the critical density then the distance is different, and for the low densities that are more likely the distance NOW to the most distant object we can see is bigger than 3 times the speed of light times the age of the Universe

Can objects move away from us faster than the speed of light?

Again, this is a question that depends on which of the many distance definitions one uses. However, if we assume that the distance of an object at time t is the distance from our position at time t to the object's position at time t measured by a set of observers moving with the expansion of the Universe, and all making their observations when they see the Universe as having age t, then the velocity (change in D per change in t) can definitely be larger than the speed of light. This is not a contradiction of special relativity because this distance is not the same as the spatial distance used in SR, and the age of the Universe is not the same as the time used in SR. In the special case of the empty Universe, where one can show the model in both special relativistic and cosmological coordinates, the velocity defined by change in cosmological distance per unit cosmic time is given by v = c ln(1+z), where z is the redshift, which clearly goes to infinity as the redshift goes to infinity, and is larger than c for z > 1.718. For the critical density Universe, this velocity is given by v = 2c[1-(1+z)^-0.5] which is larger than c for z > 3 .

PLEIADES Tycho's Supernova Remnant, named after the 18th century Danish astronomer Tycho Brahe. SIGMA ORI (Sigma Orionis). Double stars, Albireo, Mizar few are more attractive than Sigma Orionis (which has no proper name), where you see a quartet of stars, the brightest of which is also a close double. Indeed, Sigma Ori, whose five stars together shine in Orion at bright fourth magnitude (3.66) just south of Alnitak in Orion's belt, is really at the pinnacle of a small star cluster that lies a somewhat-uncertain 1150 light years away. In turn, the stars and the cluster are a part of the Orion OB1 association, which includes many of the other stars in the constellation. Sigma's main component, "AB," dominates, the two a mere 0.25 seconds of arc apart shining at magnitudes 4.2 and 5.1. Both very young hydrogen-fusing dwarfs only a few million years old, the brighter is a magnificent blue class O (09.5) star, while the lesser is class B (B0.5). The pair orbit every 170 years at a distance of about 90 Astronomical Units, very hot (32,000 and 29,600 Kelvin) surfaces, they respectively radiate at a rate of 35,000 and 30,000 Suns. Temperature and luminosity give masses of 18 and 13.5 times that of the Sun, the sum of nearly 32 solar masses making the close AB pair among the most massive of visual binaries...Even odder, the helium in "E" seems to be concentrated toward particular patches that involve a combination of the rotational and magnetic field axes. They may be related to cooler magnetic stars such as Cor Caroli, but no one really understands them.To the eye (ignoring the companion), Alnitak is 10,000 times more luminous than the Sun. However, its 31,000 Kelvin surface radiates mostly in the ultraviolet where the eye cannot see, and when that it taken into account, Alnitak's luminosity climbs to 100,000 times sol.   kaler@astro.uiuc.edu.   BETELGEUSE (Alpha Orionis). when linked @ a supernova,

 Within this cloud, stars have formed recently, and are still in process of formation. These young stars make up the so-called Orion OB1 Association; OB because the most massive, most luminous, and simultaneously hottest of these stars belong to spectral types O and B. Because they are so luminous, they use up their nuclear fuel quickly and have only a short time to live. The association can be divided in subgoups, usually called 1a, 1b, and 1c, where the subgroup 1b includes and surrounds the stars of Orion's Belt, the subgroup 1a lies north-west (preceding) of the belt stars, and the subgroup 1c contains Orion's Sword. The stars of the Orion Nebula, M42 and M43, form a subset of this group, and are sometimes separately counted as subgroup 1d, the very youngest stars of the Orion OB1 association

                        Mike (failed to mention @ www.astro.uiuc.edu/~kaler/sow/star_intro.html#neutronstars

the star is a virtual one whose physical properties and internal dynamics are numerically simulated at the points on the grid. While computers and software capable of a totally realistic numerical simulation of a complete star don't presently exist, researchers have been making progress. This picture is a movie frame from a recent numerical simulation of a supergiant star with properties intended to approximate the real star Betelgeuse. The single frame shows large convection cells and bright spots mottling the virtual supergiant's surface

Barnard's Loop Around Orion
Credit & Copyright: W. H. Wang (IfA, U. Hawaii)

Explanation: Why is the belt of Orion surrounded by a bubble? Although glowing like an emission nebula, the origin of the bubble, known as Barnard's Loop, is currently unknown. Progenitor hypotheses include the winds from bright Orion stars and the supernovas of stars long gone. Barnard's Loop is too faint to be identified with the unaided eye. The nebula was discovered only in 1895 by E. E. Barnard on long duration film exposures. Orion's belt is seen as the three bright stars across the center of the image, the upper two noticeably blue. Just to the right of the lowest star in Orion's belt is a slight indentation in an emission nebula that, when seen at higher magnification, resolves into the Horsehead Nebula. To the right of the belt stars is the bright, famous, and photogenic Orion Nebula. Such brilliance can only come from a star of great mass, Alnitak's estimated to be about 20 times solar (its dimmer companion's about 14 times solar). Like all O stars, Alnitak is a source of X-rays that seem to come from a wind that blows from its surface at nearly 2000 kilometers per second, the X- rays produced when blobs of gas in the wind crash violently into one another. Massive stars use their fuel quickly and do not live very long. Alnitak is probably only about 6 million years old (as opposed to the Sun's 4.5 billion year age) and it has already begun to die, hydrogen fusion having ceased in its core. The star will eventually become a red supergiant somewhat like Betelgeuse and almost certainly will explode as a supernova, leaving its companion orbiting a hot, madly spinning neutron star. (Thanks to Monica Shaw, who helped research this star.) RIGEL (Beta Orionis). Like its rival in Orion, Betelgeuse, Rigel (Beta Orionis) is a supergiant. Its name comes from the same root as Betelgeuse's, originally "rijl Al-jauza," meaning the "foot" of al-jauza, the Arabs "Central One." For us, the star represents the left foot of Orion, the mythical hunter. It is usually pictured as perched upon a fainter star, Cursa (Beta Eridani), which represents the hunter's foot stool. Though Rigel is Orion's Beta star, it appears to us somewhat brighter than the Alpha star, Betelgeuse, perhaps suggesting that Betelgeuse was somewhat brighter in times past. Rigel ranks 7th in visual brightness, just behind Auriga's Capella. At a distance of 775 light years, Rigel actually shines with the light of 40,000 Suns. It is a "blue supergiant," a fairly hot star with a surface temperature (11,000 Kelvin) about double that of our Sun. Its warmer temperature gives it a bluish-white light that contrasts beautifully with Betelgeuse. If the hot star's invisible ultraviolet radiation is considered, the luminosity climbs to 66,000 solar, the radiation pouring from a star 70 times the solar size. Rigel is accompanied by a fairly bright, seventh magnitude companion nine seconds of arc away. Normally such a star is easily found in a small telescope, but Rigel's brilliance nearly overwhelms it. The companion, at least 50 times farther from Rigel than Pluto is from the Sun, is itself double, the components much fainter and much less massive class B main sequence stars that are fusing hydrogen into helium. With an original mass around 17 times that of the Sun, Rigel is in the process of dying, and is most likely fusing internal helium into carbon and oxygen. The star seems fated to explode, though it might just make it under the wire as a rare heavy oxygen-neon white dwarf. Rigel is a part of a large association whose stars are related by birth. The group includes the stars of Orion's Belt, the Orion Nebula of Orion's sword and its illuminating stars, and many of the other hot blue-white stars in the constellation.

Orion on Film
Credit & Copyright: Matthew Spinelli

Explanation: Orion, the Hunter, is one of the most easily recognizable constellations in planet Earth's night sky. But Orion's stars and nebulae don't look quite as colorful to the eye as they do in this lovely photograph, taken last month from Vekol Ranch south of Phoenix, Arizona, USA. The celestial scene was recorded in a five minute time exposure using high-speed color print film and a 35mm camera mounted on a small telescope. In the picture, cool red giant Betelgeuse takes on a yellowish tint as the brightest star at the upper left. Otherwise Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse at the lower right, Bellatrix at the upper right, and Saiph at the lower left. Lined up in Orion's belt (left to right) are Alnitak, Alnilam, and Mintaka all about 1,500 light-years away, born of the constellation's well studied interstellar clouds. And if the middle "star" of Orion's sword looks reddish and fuzzy to you, it should. It's the stellar nursery known as the Great Nebula of Orion

Double stars, Albireo, Mizar few are more attractive than Sigma Orionis (which has no proper name), where you see a quartet of stars, the brightest of which is also a close double. Indeed, Sigma Ori, whose five stars together shine in Orion at bright fourth magnitude (3.66) just south of Alnitak in Orion's belt, is really at the pinnacle of a small star cluster that lies a somewhat-uncertain 1150 light years away. In turn, the stars and the cluster are a part of the Orion OB1 association, which includes many of the other stars in the constellation. Sigma's main component, "AB," dominates, the two a mere 0.25 seconds of arc apart shining at magnitudes 4.2 and 5.1. Both very young hydrogen-fusing dwarfs only a few million years old, the brighter is a magnificent blue class O (09.5) star, while the lesser is class B (B0.5). The pair orbit every 170 years at a distance of about 90 Astronomical Units, very hot (32,000 and 29,600 Kelvin) surfaces, they respectively radiate at a rate of 35,000 and 30,000 Suns. Temperature and luminosity give masses of 18 and 13.5 times that of the Sun, the sum of nearly 32 solar masses making the close AB pair among the most massive of visual binaries...Even odder, the helium in "E" seems to be concentrated toward particular patches that involve a combination of the rotational and magnetic field axes. They may be related to cooler magnetic stars such as Cor Caroli, but no one really understands them.To the eye (ignoring the companion), Alnitak is 10,000 times more luminous than the Sun. However, its 31,000 Kelvin surface radiates mostly in the ultraviolet where the eye cannot see, and when that it taken into account, Alnitak's luminosity climbs to 100,000 times sol.  

THE PLANET

The circle shows the location of the class G

star HR 1988, found in the constellation Orion, is orbited by not one, but two planets. The inner of the pair has mass at least 0.78 times the mass of Jupiter. Like so many other planets of nearby stars, it is tucked up close to its parent at a distance of only 0.13 Astronomical Units (19 million kilometers, or 33% the distance between the Sun and Mercury), causing it to

orbit in a mere 14.3 days (16% of Mercury's orbital period). Even though close to its star, its orbital eccentricity is fairly high, the planet going as far from the star as 0.17 AU and as close as

0.09 AU. The outer of the two planets has a much larger mass of 12.7 Jupiters, which makes it close to being a deuterium (heavy hydrogen) fusing brown dwarf and perhaps not a planet at all. The big one orbits in 5.95 years at a mean distance from the star of 3.68 AU (going from 2.4 to 5.0 AU over its "year"). HD 38529, is a sixth magnitude (5.95) star in the constellation Orion. Too faint to have a proper or Greek letter name, it is known best by its numbers in the Bright Star(HR) and the Henry Draper (HD) Catalogues. Classed G4 and somewhat cooler than the Sun (5675 Kelvin), the star was originally catalogued as a dwarf (G4 V), but is now considered a subgiant (G4 IV). HR 1988's distance of 138 light years reveals a luminosity 6.5 times that of the Sun, placing it squarely in the subgiant realm, in which stars have either used up their internal hydrogen fuel or will soon begin to do so, the star's mass 1.4 times solar. Like so many of the stars that have orbiting planets, HR 1988 is metal-rich, its iron abundance estimated to be about 70% greater than the Sun's

The Big Dubhe, Merak, Phecda, Megrez, Alioth, Mizar/Alcor, and Alkaid 75 light-years away and up to 30 light-years across

Big Dipper map

Dear Jim,

Your lists of achievements is impressive. It reminds me of the old joke, "he had so many degrees we called him Dr. Fahrenheit"!

 Just to advise you, I noticed a spelling mistake. I was visiting

http://www.astro.uiuc.edu/~kaler/sow/star_intro.html#supernovae

where I noticed, under the listing on supernovae, the text runs.......

...explode in a grand " supernova," an event so powerful it is easily visible even in another galaxy a huge distance away. The part of the star that is exploaded outward is so hot....

could you change the spelling on "exploaded "
                thanks from a fan,

                          Mike (failed to mention @ http://www.astro.uiuc.edu/~kaler/sow/star_intro.html#neutronstars gravity by pressure exerted **its own extreme density. should have inserted @** by)
M 45, Mel 22, the Pleiades

GRBs

 On July 2,1967 the CIA found the first example of a Gamma Ray Burst…but didn’t tell anyone… With sensors they were watching for brief x-ray and gamma-ray flashes, the telltale signatures of nuclear explosions. As intended, the Velas found flashes of gamma-rays  a billion times stronger than expected- but not from nuclear detonations near Earth. Instead, the flashes were determined to come from deep space!  The paper announcing the discovery of gamma-ray bursts was published in The Astrophysical Journal in 1973 (Klebesadel, Strong and Olsen).

Gamma-ray bursts are impressive, believed to be the most powerful explosions in the Universe Gamma ray bursts release extremely large amount of energy - approximately 10^52 ergs (or 10^45 joules), with the most extreme bursts releasing up to 10^54 ergs.

This is the equivalent of turning a star like the Sun into pure energy (using Einstein's famous equation E=mc^2). This is also the amount of energy released by 1000 stars like the Sun over their entire lifetime! In practice, over the few seconds that a gamma ray burst occurs, it releases almost the same amount of energy as the entire Universe!

 the nature of the bursters themselves is still shrouded in mystery.

Gamma rays are the most energetic form of light, packing a million or more times the energy of visible light photons. If you could see gamma rays, the familiar skyscape of steady stars would be replaced by some of the most bizarre objects known to modern astrophysics -- and some which are unknown. From 1991-2000, BATSE detected 2704 GRBs, much more than ever previously recorded. The above final sky map of GRB locations (and fluence) shows them to occur at random locations on the sky - strong evidence that GRBs occur across our universe continue to make monumental discoveries, including identifying mysterious gamma-ray bursts that uniquely illuminate the early universe, discovery of a whole new class of QSOs, and discovery of objects so strange that astronomers can't yet figure out what they are.

Most bursts also show an asymmetry, with the leading edges of shorter duration than trailing edges. This applies to both the overall burst as well as to sub-structures within a burst. A unique feature of gamma-ray bursts is their high-energy emission: almost all of the power is emitted above 50 keV. Most bursts have a rather simple continuum spectrum which appears somewhat similar in shape when integrated over the entire burst and when sampled on various time scales within a burst. If the sources are distributed homogeneously in Euclidean space, i.e. the density and luminosity function are independent of position throughout the volume of space observed, then the integral intensity distribution will be N(>P) = P-3/2. A search for line features (either absorption or emission features) with the detectors of BATSE-Compton Observatory has thus far been unable to confirm the earlier reports of spectral line features from gamma-ray bursts. gamma-ray bursts at cosmological distances would exhibit time dilation effects unobservable from other astronomical objects. In accordance with standard cosmology, the more distant bursts are fainter and they are receding faster. Thus they would show a larger time dilation than the nearer, more intense bursts. The entire burst would be "stretched" so that the fainter bursts (and presumably farther) would be, on the average, longer. In addition, individual pulse structures within bursts and the time intervals between these pulse structures would be similarly stretched. Finally, the spectra of the fainter, more distant bursts would be redshifted, which, in essence, is a time dilation of the wavelength of emission in the observer's frame.

Due to the complexity of the gamma-ray burst time structures and the wide range of their durations, any dilation effects can only be tested in a statistical sense.The sites must be consistent with the observed isotropy and inhomogeneity, the energy source must be sufficient to produce the observed intensities for the distances assumed, and the emission mechanism must be able to reproduce the time scales and the spectra observed in bursts. The final step, deriving the observed burst properties from considerations of the energy transport, has been the most difficult. The paucity of X-rays, for example, presents difficulties for processes occurring near the surface of a neutron star. The intense gamma radiation would be expected to heat the neutron star surface, producing an intense thermal X-ray component, which has not been observed. Researchers identified some with exotic black holes, neutron stars, and distant flaring galaxies. But 170 of the cataloged sources, shown in the above all-sky map, remain unidentified. Many sources in this gamma-ray mystery map likely belong to already known classes of gamma-ray emitters and are simply obscured or too faint to be otherwise positively identified. However, astronomers have called attention to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent a large unknown class of galactic gamma-ray emitters. Infrared images from the Hubble have also shown that hidden at the center of this activity are what seem to be disks of matter spiraling into a black hole with a billion times the mass of the Sun! The diffuse gamma-ray glow from the plane of our Milky Way Galaxy runs horizontally through the false-color image. The brightest spots in the galactic plane (right of center) are pulsars, spinning magnetized neutron stars formed in the violent crucibles of stellar explosions. Above and below the plane, quasars, believed to be powered by supermassive black holes, produce gamma-ray beacons at the edges of the universe. The nature of many of the fainter sources remains unknown. GRB 000301C came into view, detailing unusual behavior. The Hubble Space Telescope captured the above image and was the first to obtain an accurate distance to the explosion, placing it near redshift 2, most of the way across the visible universe. The Keck II Telescope in Hawaii quickly confirmed and refined the redshift. Even today, no one is sure what type of explosion this was. Unusual features of the light curve are still being studied, and no host galaxy appears near the position of this explosionThis was a *very* short burst, lasting just 30 milliseconds (0.03 seconds)! Swift was able to slew to the burst in well under a minute. Analysis of the X-Ray Telescope shows a very faint detection of X-rays from the burst, and in fact this is the faintest X-ray afterglow Swift has yet detected this early from a burst.

This is potentially a very exciting burst. It appears very near a galaxy at a redshift of 0.226, corresponding to a distance of 2.7 billion light years-- relatively close by, as these things go. The galaxy itself is a member of the cluster NSC J123610+285901. If the burst was from that galaxy, it has a projected distance of about 100,000 light years from the galaxy center-- about the diameter of our own Milky Way Galaxy.

Optical Afterglow

This GRB's optical counterpart had an optical magnitude of 19.6 in the V (visible) Filter region.

It happened so far away that common human distance measures are inadequate to describe it. Furthermore, astronomers do not even claim to know exactly what happened. What is known is that satellites across our Solar System reported on 2000 January 31 a tremendous explosion of gamma rays had occurred towards some previously uninteresting direction but also was able to estimate that the cosmologically-induced redshift was an astonishing 4.5 -- placing GRB000131 farther across the universe than any explosion so measured.    

This vast distance indicates that GRB000131 occurred just as galaxies like our Milky Way were forming, and so qualifies gamma ray bursts as unique probes of this ancient epoch. Gamma rays are the most energetic form of light, packing a million or more times the energy of visible light photons. If you could see gamma rays, the familiar skyscape of steady stars would be replaced by some of the most bizarre objects known to modern astrophysics -- and some which are unknown.

The figure to the right is the discovery image of the afterglow of the burst.

Scientists have detected a flash of light from across the Galaxy so powerful that it bounced off the Moon and lit up the Earth's upper atmosphere. The flash was brighter than anything ever detected from beyond our Solar System and lasted over a tenth of a second. NASA and European satellites and many radio telescopes detected the flash and its aftermath on December 27, 2004. Two science teams report about this event at a special press event today at NASA headquarters. A multitude of papers are planned for publication.Many other observers tried to detect the afterglow of this burst, but very little emission was seen at visible wavelengths. Dr. Reichart?s observations yielded an approximate distance to the burst, and later infrared observations by a team led by Dr. Nobuyaki Kawai from the Tokyo Institute of Technology used the NAOJ 8.2-meter Subaru telescope to measure a precise distance to the explosion: 12.8 billion light-years. This is less than one billion light years after the Big Bang! From 1991-2000, BATSE detected 2704 GRBs, much more than ever previously recorded.

The above final sky map of GRB locations (and fluence) shows them to occur at random locations on the sky - strong evidence that GRBs occur across our universe continue to make monumental discoveries, including identifying mysterious gamma-ray bursts that uniquely illuminate the early universe, discovery of a whole new class of QSOs, and discovery of objects so strange that astronomers can't yet figure out.

Gamma-ray bursts in general are notoriously difficult to study, but the shortest ones have been next to impossible to pin down," said Dr. Neil Gehrels, principal investigator for the Swift satellite at NASA's Goddard Space Flight Center, Greenbelt, Md. "All that has changed. We now have the tools in place to study these events," he said. Gamma-ray bursts, first detected in the 1960s, are the most powerful explosions known. They are random, fleeting and can occur from any region of the sky. Two years ago, scientists discovered longer bursts, lasting more than two seconds, arise from the explosion of very massive stars. About 30 percent of bursts are short and under two seconds. The Swift satellite detected a short burst on May 9, and NASA's High-Energy Transient Explorer (HETE) detected another on July 9. The May 9 event marked the first time scientists identified an afterglow for a short gamma-ray burst, something commonly seen after long bursts.
Images above: These Hubble Space Telescope images show the fading afterglow and host galaxy of the HETE short burst of July 9, 2005. The images are taken 5.6, 9.8, 18.6, and 34.7 days after the burst, respectively. The bright, point-like afterglow is located to the left, and fades away over the course of the month following the burst.   

 - Short Gamma Ray Bursts Localized What causes gamma-ray bursts? The most energetic type of explosions known in the cosmos has been an enigma since discovered over 30 years ago. It now appears that there may not be one unique type of progenitor. Long duration gamma-ray bursts (GRBs) have been localized, over the past few years, to blue regions in the universe rich in star formation. Massive young stars nearing the end of their short lives commonly explode in these regions. Astronomers associate these long duration GRBs, that can last from seconds to minutes, with a type of stellar explosion common in young massive stars. Over the past few months, short duration GRBs have finally been localized and found to occur in different types of regions -- not only blue regions rich in star formation. Many astronomers therefore now theorize that short GRBs, which typically last less than one second, are the result of a different progenitor process than long GRBs. A leading model is that a short GRB will occur when a neutron star either impacts another neutron star or a black hole. Such collisions may occur well after star-forming regions have otherwise burned out. Pictured in the above illustration, two energized neutrons stars finally approach each other in their orbits, a death spiral that might end with a short GRB what they are.

The short-hard gamma-ray bursts are indeed unusual and fascinating events.  They have been known for many years but we still know very little about them.  At present the leading theories are that they are due to explosions on the surfaces
                                    of highly magnetized neutron stars(which are also known as magnetars) or that they are due to merging compact objects such
                                    as neutron stars, white dwarfs, or black holes.Both of these theories have problems and the solution to the mystery

of the short-hard gamma-ray bursts
                                    will probably have to wait until we have collect a lot more data on them.

Some scientists have speculated that the short-hard
                                    gamma-ray 

bursts may be caused by some sort of effect due to higher dimensions or interactions between branes, but there is no
                                    evidence to support these idea.  Still, it is an interesting possibility. At present
                                    there is no e-mail list for Swift or for reports on new theories regarding gamma-ray bursts. 
                                    Web sites such as<http://www.space.com/> are good places to look for up-to-date information about space and astrophysics. 
                                    If you are interested in more technicalinformation look at the Gamma-Ray Burst Coordinates Network(http://gcn.gsfc.nasa.gov/), but please be aware that this information is aimed at professional astrophysicists, not at the general public.

stephen holland Swift Science Centre
                                    From: spacermike00@yahoo.ca To: swifthelp@olegacy.gsfc.nasa.gov

 Subject: [Swift #413] short grb's I am awed by short grb's, I even like that no-one can positively identify their source,
                                    which tends to make them even more mysterious. With limited knowledge of M theory and the holographic principle, but with
                                    lots of imagination, I wonder if theories not mentioned by Mr. Hawkings et al could include: membrane activity, or extra-dimensional
                                    interference. Merging black holes (as suggested by some) on a daily basis just doesn't seem like a reasonable scenario. I
                                    was hoping you could keep me on an email list for reports as they become available. thanks mike

Dark energy

In cosmology, dark energy is a hypothetical form of energy which permeates all of space and has strong negative pressure. According to the theory of relativity, the effect of such a negative pressure is qualitatively similar to a force acting in opposition to gravity at large scales. Invoking such an effect is currently the most popular method for explaining the observations of an accelerating universe as well as accounting for a significant portion of the missing mass in the universe.Two proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously, and quintessence, a dynamic field whose energy density can vary in time and space. Distinguishing between the alternatives requires high-precision measurements of the expansion of the universe to understand how the speed of the expansion changes over time. The rate of expansion is parameterized by the cosmological equation of state. Measuring the equation of state of dark energy is one of the biggest efforts in observational cosmology today.Adding a cosmological constant to the standard theory of cosmology (i.e. the FLRW metric) has led to a model for cosmology known as the Lambda-CDM model. This model is in very good agreement with established cosmological observations. The term dark energy was coined by Michael Turner.

Due to the complexity of the gamma-ray burst time structures and the wide range
                                    of their durations, any dilation effects can only be tested in a statistical sense.The sites must be consistent with the observed
                                    isotropy and inhomogeneity, the energy source must be sufficient to produce the observed intensities for the distances assumed,
                                    and the emission mechanism must be able to reproduce the time scales and the spectra observed in bursts. The final step, deriving
                                    the observed burst properties from considerations of the energy transport, has been the most difficult. The paucity of X-rays,
                                    for example, presents difficulties for processes occurring near the surface of a neutron star. The intense gamma radiation
                                    would be expected to heat the neutron star surface, producing an intense thermal X-ray component, which has not been observed.
                                    Researchers identified some with exotic black holes, neutron stars, and distant flaring galaxies. But 170 of the cataloged sources, shown in the above all-sky map, remain unidentified. Many sources in this gamma-ray mystery map likely belong to already known classes of gamma-ray emitters and are simply obscured or too
                                    faint to be otherwise positively identified. However, astronomers have called attention to the ribbon of sources winding through the plane of the galaxy, projected here along the middle of the map, which may represent
                                    a large unknown class of galactic gamma-ray emitters. Infrared images from the Hubble have also shown that hidden at the center of this activity are what seem to be disks of matter spiraling into a black hole with a billion times the mass of
                                       the Sun! The diffuse gamma-ray glow from the plane of our Milky Way Galaxy runs horizontally through the false-color image. The brightest spots in the galactic plane (right of center) are pulsars, spinning magnetized neutron stars formed in the violent crucibles of stellar explosions. Above and below the plane, quasars, believed to be powered by supermassive black holes, produce gamma-ray beacons at the edges of the universe. The nature of many of the fainter sources remains unknown. GRB 000301C came into view, detailing unusual behavior. The Hubble Space Telescope captured the above image and was the first to obtain an accurate distance to the explosion, placing it near redshift 2, most of the way across the visible universe. The Keck II Telescope in Hawaii quickly confirmed and refined the redshift. Even today, no one is sure what type of explosion this was. Unusual features of the light curve are still being studied, and no host galaxy appears near the position of this explosion. The graph below shows the corresponding response of an orbiting gamma-ray detector as its counting rate suddenly climbs and falls recording the passage of the mysterious burst. Originating far across the
                                    Universe, gamma-ray bursts are now known to be the most powerful explosions since the big bang and may yet prove to be useful tools for exploring the distant cosmos.  Department of Physics and Astronomy 

                                    Director,
                                    NASA

This was a *very* short burst, lasting just 30 milliseconds (0.03 seconds)! Swift was able to slew to the burst in well under a minute. Analysis of the X-Ray Telescope shows a very faint detection of X-rays from the burst, and in fact this is the faintest X-ray afterglow Swift has yet detected this early from a burst.

This is potentially a very exciting burst. It appears very near a galaxy at a redshift of 0.226, corresponding to a distance of 2.7 billion light years-- relatively close by, as these things go. The galaxy itself is a member of the cluster NSC J123610+285901. If the burst was from that galaxy, it has a projected distance of about 100,000 light years from the galaxy center-- about the diameter of our own Milky Way Galaxy.

Optical Afterglow

This GRB's optical counterpart had an optical magnitude of 19.6 in the V (visible) Filter region.

In the summer of 1054 A.D. Chinese astronomers reported that a star in the constellation of Taurus suddenly became as bright as the full Moon. Fading slowly, it remained visible for over a year. It is now understood that a spectacular supernova explosion - the detonation of a massive star whose remains are now visible as the Crab Nebula- was responsible for the apparition. The core of the star collapsed to form a rotating neutron star or pulsar, one of the most exotic objects known These exotic sources of gamma-rays are believed to be highly magnetized spinning neutron stars called Magnetars. Imaginatively cataloged as SGR 1900+14, this magnetar is estimated to have been born in a supernova explosion about 1,500 years ago and to have a magnetic field 500,000,000,000,000 times stronger than Earth's.

 majestic view of the Eskimo Nebula, a planetary nebula, the glowing remains of a dying, Sun-like star

Dark matter and dark energy are becoming accepted invisible components of our universe, much like oxygen and nitrogen have become established invisible components of Earth-bound air. In comprehending the nature and origin of the formerly invisible, however, we are only just exiting the cosmological dark age. Relatively unexplored concepts such as higher spatial dimensions, string theories of fundamental particles, quintessence, and new forms of inflation all vie for cornerstone roles in a more complete theory. As understanding invisible air has led to such useful inventions as the airplane and the oxygen mask, perhaps understanding dark matter and dark energy can lead to even more spectacular and useful inventions

Does our universe have higher but unusual spatial dimensions? This idea has been gaining popularity to help explain why vastly separated parts of our universe appear so similar, and why the geometry of our universe does not seem to result naturally from the amounts of matter it seems to contain. In a new incarnation of an old extra-dimensional idea, some astrophysicists hypothesize that we live in a universe dubbed Ekpyrotic, where our four dimensions (three spatial plus one time) resulted from the fiery collision of two four-dimensional spaces (branes) in a five-dimensional universe. I study astronomy as a hobby, several hours daily, love the awesome wonder of it all and am very perplexed by FRED's.  What if as the Membrane theory is correct, there are continued touches of these membranes creating these gamma ray bursts, if 11 B light years away would black holes have evolved enough to be the source
We don't know of any proposed explanations of gamma-ray bursts
from M theory.  In fact, the only prediction we know of about
the consequences of two branes touching is to cause the Big
Bang, which of course is completely different from gamma-ray
bursts: http://news.bbc.co.uk/1/hi/sci/tech/1270726.stm On the other hand, there is a growing body of evidence linking gamma-ray bursts with a certain type of supernova: http://imagine.gsfc.nasa.gov/docs/features/news/26jun03.html
So these would be the birth of black holes, the endpoint of evolution for the most massive stars.  They consume their nuclear fuel at a furious rate, only lasting about 10 million years.  So there is no problem explaining even the most distant gamma-ray bursts this way.  Hope this helps, Koji & Scott for "Ask a High Energy Astronomer"

spreadtheword75@hotmail.com Koji Mukai
                                    <koji@lheapop.gsfc.nasa.gov> Date: October 21, 2004

at the Laue-Langevin Institute, carefully dropped neutrons were seen to appear at only discrete heights. The effect does not in itself, however, imply attributes of a possible quantum field nature of gravity. they are not, at the most essential level, even identifiably separable from other such particles arbitrarily far away

The sun unlashed this powerful solar flare on January 4, 2002 -- researchers say it could be the most complex coronal mass ejection ever witnessed.

info@SkyandTelescope.com

      Several phenomenon I have witnessed lately include some rather brilliant fluctuations of Betelguese on March 16 & 17/05  around 11pm (est) until 2am from Brampton Ontario, Canada. On both nights with clear black skies, colour changed violently from red to white and luminosity fluctuations were very drastic as well. I truly believed it would supernova right before my eyes! I compared this unusual behaviour with other stars which all appeared normal, and with other nights when Betelguese appeared normal (for it). Can someone get back to me on this?   Noctilucent clouds (NLCs) are a mystery. They hover near the edge of space, far above ordinary clouds. Some researchers believe they're seeded by space dust. Others say they're a sign of global warming. Whatever they are, they're beautiful, and last week's sightings in Europe mark the beginning of the 2005 noctilucent cloud season. Northern summer is the best time to spot them

 They hover on the edge of space. Thin, wispy clouds, glowing electric blue. Some scientists think they're seeded by space dust. Others suspect they're a telltale sign of global warming.

They're called noctilucent or "night-shining" clouds (NLCs). And whatever causes them, they're lovely.

"Over the past few weeks we've been enjoying outstanding views of these clouds above the southern hemisphere," said space station astronaut Don Pettit . "We routinely see them when we're flying over Australia and the tip of South America." Electric blue clouds viewed from the ISS.Sky watchers on Earth have seen them, too, glowing in the night sky after sunset, although the view from Earth-orbit is better.

Spiral galaxy NGC 7331 is often touted as an analog to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog. Since the galaxy's disk is inclined to our line-of-sight, deep telescopic exposures often result in an image that evokes a strong sense of depth. The effect is further enhanced in this well-framed view by the galaxies that lie beyond this beautiful island universe. The background galaxies are about one tenth the apparent size of NGC 7331 and so lie roughly ten times farther away.

Explanation: Spectacular explosions keep occurring in the binary star system named RS Ophiuchi. Every 20 years or so, the red giant star dumps enough hydrogen gas onto its companion white dwarf star to set off a brilliant thermonuclear explosion on the white dwarf's surface. At about 2,000 light years distant, the resulting nova explosions cause the RS Oph system to brighten up by a huge factor and become visible to the unaided eye. The red giant star is depicted on the right of the above drawing, while the white dwarf is at the center of the bright accretion disk on the left. As the stars orbit each other, a stream of gas moves from the giant star to the white dwarf. Astronomers speculate that at some time in the next 100,000 years, enough matter will have accumulated on the white dwarf to push it over the Chandrasekhar Limit,

  laws of the universe  

x-ray image of the Centaurus cluster of galaxies…optical

Clusters of galaxies are some of the largest structures in the universe.  The mass within a cluster is divided up between the stars (about 10% of the cluster mass), a hot X-ray emitting gas (20% of the cluster), and dark matter (the remaining 70%). Scientists now know that the gravitational effect of the dark matter is responsible for holding the cluster together. But the nature and detailed distribution of the dark matter is still a mystery.Studying them provides important clues as to the make-up of the universe, with regard to both how structures form and the chemical composition of the universe.

Discovered in 1866, main belt asteroid 87 Sylvia lies 3.5 AU from the Sun, between the orbits of Mars and Jupiter. Also shown in recent years to be one in a growing list of double asteroids, new observations during August and October 2004 made at the Paranal Observatory convincingly demonstrate that 87 Sylvia in fact has two moonlets - the first known triple asteroid system. At the center of this composite of the image data, potato-shaped 87 Sylvia itself is about 380 kilometers wide. The data show inner moon, Remus, orbiting Sylvia at a distance of about 710 kilometers once every 33 hours, while outer moon Romulus orbits at 1360 kilometers in 87.6 hours. Tiny Remus and Romulus are 7 and 18 kilometers across respectively. Because 87 Sylvia was named after Rhea Silvia, the mythical mother of the founders of Rome, the discoverers proposed Romulus and Remus as fitting names for the two moonlets.  This is a composite image of Chandra X-ray (blue) and VLA radio (red) observations showing the inner 4,000 light years of a magnetized jet in Centaurus A. Purple regions are bright in both radio and X-ray. The jet originates from the vicinity of the supermassive black hole at the center of the galaxy (lower right hand corner of the image).The radio observations, taken between 1991 and 2002, showed that the inner portion of the jet is moving away from the center of the galaxy at speeds of about half the speed of light. Most of the X-rays from the jet are produced farther out where the jet stalls as it plows through the gas in the galaxy. The collision of the jet with the galactic gas generates a powerful shock wave that produces the extremely high-energy particles responsible for the X-rays.

Z Machine Sets Unexpected Earth Temperature Record  in excess of two billion Kelvin,

Explanation: Why is this plasma so hot? Physicists aren't sure. What is known for sure is that the Z Machine running at Sandia National Laboratories created a plasma that was unexpectedly hot. The plasma reached a temperature in excess of two billion Kelvin, making it arguably the hottest human made thing ever in the history of the Earth and, for a brief time, hotter than the interiors of stars. The Z Machine experiment, pictured above, purposely creates high temperatures by focusing 20 million amps of electricity into a small region further confined by a magnetic field. Vertical wires give the Z Machine its name. During the unexpected powerful contained explosion, the Z machine released about 80 times the world's entire electrical power usage for a brief fraction of a second. Experiments with the Z Machine are helping to explain the physics of Solar flares, design more efficient nuclear fusion plants, test materials under extreme heat, and gather data for the computer modeling of nuclear explosions  

Poké Vaporeon

Centauri globular cluster.

The distance between Omega Centauri and Epsilon Centauri is the same distance as between Epsilon Centauris and Centaurus A. Or, connect the imaginary line between Omega Centauri and Iota Centauri and aim your telescope at the middle.

Over 200 point-like X-ray sources have been identified and studied in Cen A. Because of their distribution around the center of the galaxy, it is believed that most of these sources are X-ray binaries in which a neutron star or stellar-sized black hole is accreting matter from a nearby companion star. A few may be supernova remnants or unrelated, more distant background galaxies.

The N44 Superbubble 250 light-year hole and astronomers are trying to figure out why. An unexpected clue of hot X-ray emitting gas was recently been detected escaping  One possibility is black holes or some other exotic energy/matter yet unknown

d gamma ray burststo blackholes

Reality is non-local”.  communicate faster than light   

by Mike Milne

Time Line of the Universe -- The expansion of the universe over most of it's history

Big Dipper map

 One hundred years ago, he wrote four papers which revolutionized our understanding of the Universe. The papers outlined; the idea that light could behave as a quantized particle (a photon), an explanation of the thermal motion of atoms and molecules (at a time when atoms themselves were just theories), a theory reconciling motion and the constant speed of light (Special Relativity), and the idea of mass-energy equivalence (E=mc²). Virtually every facet of our modern exploration of the Universe is touched by his now century old insights, along with his later theory of gravity and space-time - General Relativity.

missing mass problem

Scientists using different methods to determine the mass of galaxies have found a discrepancy that suggests ninety percent of the universe is matter in a form that cannot be seen. Some scientists think dark matter is in the form of massive objects, such as black holes, that hang out around galaxies unseen. Other scientists believe dark matter to be subatomic particles that rarely interact with ordinary matter. This paper is a review of current literature. I look at how scientists have determined the mass discrepancy, what they think dark matter is and how they are looking for it, and how dark matter fits into current theories about the origin and the fate of the universe. MACHOs are made of 'ordinary' matter, which is called baryonic matter. WIMPs, on the other hand, are the little weak subatomic dark matter candidates, which are thought to be made of stuff other than ordinary matter, called non-baryonic matter. Astronomers search for MACHOs and particle physicists look for WIMPs.most scientists concede that dark matter is a combination of baryonic MACHOs and non-baryonic WIMPs.

We believe that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). This is "stuff" which cannot be seen directly -- so what makes us think that it exists at all? Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the Cosmic Microwave Background enough to form the large-scale structures that we see in the universe today.

Tycho's Supernova Remnant, named after the 18th century Danish astronomer Tycho Brahe. SIGMA ORI (Sigma Orionis). Double stars, Albireo, Mizar few are more attractive than Sigma Orionis (which has no proper name), where you see a quartet of stars, the brightest of which is also a close double. Indeed, Sigma Ori, whose five stars together shine in Orion at bright fourth magnitude (3.66) just south of Alnitak in Orion's belt, is really at the pinnacle of a small star cluster that lies a somewhat-uncertain 1150 light years away. In turn, the stars and the cluster are a part of the Orion OB1 association, which includes many of the other stars in the constellation. Sigma's main component, "AB," dominates, the two a mere 0.25 seconds of arc apart shining at magnitudes 4.2 and 5.1. Both very young hydrogen-fusing dwarfs only a few million years old, the brighter is a magnificent blue class O (09.5) star, while the lesser is class B (B0.5). The pair orbit every 170 years at a distance of about 90 Astronomical Units, very hot (32,000 and 29,600 Kelvin) surfaces, they respectively radiate at a rate of 35,000 and 30,000 Suns. Temperature and luminosity give masses of 18 and 13.5 times that of the Sun, the sum of nearly 32 solar masses making the close AB pair among the most massive of visual binaries...Even odder, the helium in "E" seems to be concentrated toward particular patches that involve a combination of the rotational and magnetic field axes. They may be related to cooler magnetic stars such as Cor Caroli, but no one really understands them.To the eye (ignoring the companion), Alnitak is 10,000 times more luminous than the Sun. However, its 31,000 Kelvin surface radiates mostly in the ultraviolet where the eye cannot see, and when that it taken into account, Alnitak's luminosity climbs to 100,000 times sol.   kaler@astro.uiuc.edu.   BETELGEUSE (Alpha Orionis). when linked @ a supernova,

Dear Jim,

Your lists of achievements is impressive. It reminds me of the old joke, "he had so many degrees we called him Dr. Fahrenheit"!

 Just to advise you, I noticed a spelling mistake. I was visiting

http://www.astro.uiuc.edu/~kaler/sow/star_intro.html#supernovae

where I noticed, under the listing on supernovae, the text runs.......

...explode in a grand " supernova," an event so powerful it is easily visible even in another galaxy a huge distance away. The part of the star that is exploaded outward is so hot....

could you change the spelling on "exploaded "
                thanks from a fan,

                          Mike (failed to mention @ http://www.astro.uiuc.edu/~kaler/sow/star_intro.html#neutronstars gravity by pressure exerted **its own extreme density. should have inserted @** by)
M 45, Mel 22, the Pleiades

With brilliant Betelgeuse and Rigel dominating great Orion, we pay little heed to the individual stars of the Hunter's belt except as a group, the trio the Arabs called the "string of pearls." All second magnitude, Johannes Bayer seems to have named the stars Delta, Epsilon, and Zeta from right to left. The name of the left hand star, Alnitak (Zeta Orionis), stands in for the whole string, and comes from a phrase that means "the belt of al jauza," "al jauza" the Arabs female "central one." Separate Alnitak from the belt and it becomes a most remarkable star in its own right, the brightest class O star in the sky, a hot blue supergiant. Tucked right next to it is a companion, a blue class B hydrogen-fusing star about three seconds of arc away, the pair orbiting each other with a period estimated to be thousands of years long. The region around Alnitak is remarkable as well, containing several dusty clouds of interstellar gas, including the famed "Horsehead Nebula" to the south. Alnitak approaches first magnitude even though at a distance of 800 light years. To the eye (ignoring the companion), it is 10,000 times more luminous than the Sun. However, its 31,000 Kelvin surface radiates mostly in the ultraviolet where the eye cannot see, and when that it taken into account, Alnitak's luminosity climbs to 100,000 times solar. A planet like the Earth would have to be 300 times farther from Alnitak than Earth is from the Sun (8 times Pluto's distance) for life like ours to survive.

Why is the belt of Orion surrounded by a bubble? Although glowing like an emission nebula, the origin of the bubble, known as Barnard's Loop, is currently unknown. Progenitor hypotheses include the winds from bright Orion stars and the supernovas of stars long gone. Barnard's Loop is too faint to be identified with the unaided eye. The nebula was discovered only in 1895 by E. E. Barnard on long duration film exposures. Orion's belt is seen as the three bright stars across the center of the image, the upper two noticeably blue. Just to the right of the lowest star in Orion's belt is a slight indentation in an emission nebula that, when seen at higher magnification, resolves into the Horsehead Nebula. To the right of the belt stars is the bright, famous, and photogenic Orion Nebula. Such brilliance can only come from a star of great mass, Alnitak's estimated to be about 20 times solar (its dimmer companion's about 14 times solar). Like all O stars, Alnitak is a source of X-rays that seem to come from a wind that blows from its surface at nearly 2000 kilometers per second, the X- rays produced when blobs of gas in the wind crash violently into one another. Massive stars use their fuel quickly and do not live very long. Alnitak is probably only about 6 million years old (as opposed to the Sun's 4.5 billion year age) and it has already begun to die, hydrogen fusion having ceased in its core. The star will eventually become a red supergiant somewhat like Betelgeuse and almost certainly will explode as a supernova, leaving its companion orbiting a hot, madly spinning neutron star. (Thanks to Monica Shaw, who helped research this star.) RIGEL (Beta Orionis). Like its rival in Orion, Betelgeuse, Rigel (Beta Orionis) is a supergiant. Its name comes from the same root as Betelgeuse's, originally "rijl Al-jauza," meaning the "foot" of al-jauza, the Arabs "Central One." For us, the star represents the left foot of Orion, the mythical hunter. It is usually pictured as perched upon a fainter star, Cursa (Beta Eridani), which represents the hunter's foot stool. Though Rigel is Orion's Beta star, it appears to us somewhat brighter than the Alpha star, Betelgeuse, perhaps suggesting that Betelgeuse was somewhat brighter in times past. Rigel ranks 7th in visual brightness, just behind Auriga's Capella. At a distance of 775 light years, Rigel actually shines with the light of 40,000 Suns. It is a "blue supergiant," a fairly hot star with a surface temperature (11,000 Kelvin) about double that of our Sun. Its warmer temperature gives it a bluish-white light that contrasts beautifully with Betelgeuse. If the hot star's invisible ultraviolet radiation is considered, the luminosity climbs to 66,000 solar, the radiation pouring from a star 70 times the solar size. Rigel is accompanied by a fairly bright, seventh magnitude companion nine seconds of arc away. Normally such a star is easily found in a small telescope, but Rigel's brilliance nearly overwhelms it. The companion, at least 50 times farther from Rigel than Pluto is from the Sun, is itself double, the components much fainter and much less massive class B main sequence stars that are fusing hydrogen into helium. With an original mass around 17 times that of the Sun, Rigel is in the process of dying, and is most likely fusing internal helium into carbon and oxygen. The star seems fated to explode, though it might just make it under the wire as a rare heavy oxygen-neon white dwarf. Rigel is a part of a large association whose stars are related by birth. The group includes the stars of Orion's Belt, the Orion Nebula of Orion's sword and its illuminating stars, and many of the other hot blue-white stars in the constellation. Orion, the Hunter, is one of the most easily recognizable constellations in planet Earth's night sky. But Orion's stars and nebulae don't look quite as colorful to the eye as they do in this lovely photograph, taken last month from Vekol Ranch south of Phoenix, Arizona, USA. The celestial scene was recorded in a five minute time exposure using high-speed color print film and a 35mm camera mounted on a small telescope. In the picture, cool red giant Betelgeuse takes on a yellowish tint as the brightest star at the upper left. Otherwise Orion's hot blue stars are numerous, with supergiant Rigel balancing Betelgeuse at the lower right, Bellatrix at the upper right, and Saiph at the lower left. Lined up in Orion's belt (left to right) are Alnitak, Alnilam, and Mintaka all about 1,500 light-years away, born of the constellation's well studied interstellar clouds. And if the middle "star" of Orion's sword looks reddish and fuzzy to you, it should. It's the stellar nursery known as the Great Nebula of Orion.

This picture is a movie frame from a recent numerical simulation of a supergiant star with properties intended to approximate the real star Betelgeuse. The single frame shows large convection cells and bright spots mottling the virtual supergiant's surface. Simulation movies show these surface features changing substantially with time. Encouragingly, telescopic observations indicate that the surface of Betelgeuse does indeed have prominent large scale features and the well-known star's brightness variations are detectable with the unaided eye. The real supergiant Betelgeuse is some 2,500 degrees cooler than, and 620 times the size of the Sun.

Orion Nebula: The Hubble View

LL Ori and the Orion NebulaThe bright region of the nebula around the Trapezium is called "Regio Huygheniana", which is sharply limited by the "Frons" toward the lower-surface-brightness "Regio Subnebulosa" in the southeast (lower left) which contains as its brightest star Theta2 Orionis (nearest to the "Frons"); Theta1 is the brightest Trapezium star.

The Light of Ancient Stars

November 3rd, 2005

The Spitzer Space Telescope once again dazzles us with its capabilities at infrared wavelengths. Now it’s the detection of what may be some of the earliest objects in the universe, the hypothetical Population III stars that would have formed a mere 200 million years after the Big Bang itself. These short-lived objects were probably over a hundred times more massive than our Sun. If the scientists investigating the recent Spitzer data are right, they are looking at the redshifted ultraviolet light of these ancient stars, stretched to lower energy levels by the expansion of the universe and now detected as a diffuse glow of infrared light.

The top panel is an image from NASA’s Spitzer Space Telescope of stars and galaxies in the constellation Draco, covering about 50 by 100 million light-years (6 to 12 arcminutes). This is an infrared image showing wavelengths of 3.6 microns, below what the human eye can detect. The bottom panel is the resulting image after all the stars, galaxies and artifacts were masked out. The remaining background has been enhanced to reveal a glow that is not attributed to galaxies or stars. This might be the glow of the first stars in the universe.

 A Higher Dimensional Universe
Does our universe have higher but unusual spatial dimensions? This idea has been gaining popularity to help explain why vastly separated parts of our universe appear so similar, and why the geometry of our universe does not seem to result naturally from the amounts of matter it seems to contain. In a new incarnation of an old extra-dimensional idea, some astrophysicists hypothesize that we live in a universe dubbed Ekpyrotic, where our four dimensions (three spatial plus one time) resulted from the fiery collision of two four-dimensional spaces (branes) in a five-dimensional universe. This big-bang hypothesis is meant to compete with another big-bang hypothesis that our universe underwent a superluminal inflation event in the distant past, and does make distinct testable predictions. Above, a dynamic three-dimensional drawing (two spatial plus one time) of a four-dimensional depiction of a five-dimensional cube (a hypercube with four spatial dimensions is also known as a tesseract) is shown. Donning red-blue glasses will give the best multi-dimensional perspective.

 Where did the gold in your jewelry originate? No one is completely sure. The relative average abundance in our Solar System appears higher than can be made in the early universe, in stars, and even in typical supernova explosions. Some astronomers now suggest that neutron-rich heavy elements such as gold might be most easily made in rare neutron-rich explosions such as the collision of neutron stars. In this case, the subject is one of the most famous constellations in the night sky, Crux, the Southern Cross. Gacrux or gamma Crucis is the bright red giant star only 88 light-years distant that forms the top of the Cross seen here near top center. Acrux, the hot blue star at the bottom of the Cross is about 320 light-years distant. Actually a binary star system, Acrux is the alpha star of the compact Southern Cross and lies along a line pointing from Gacrux to the South Celestial Pole, off the lower right edge of the picture. The top of the cross is marked by the lovely pale red star Gamma Crucis, which is in fact a red giant star about 120 light-years distant. Stars of the grand constellation Centaurus almost engulf the Southern Cross with blue giant Beta Centauri, and yellowish Alpha Centauri, appearing as the brightest stars to the left of Gamma Crucis. At a distance of 4.3 light-years, Alpha Centauri, the closest star to the Sun, is actually a triple star system which includes a star similar to the Sun. The Earth's magnetic field which deflects compass needles is measured to be about 1 Gauss, while the strongest fields sustainable in earthbound laboratories are about 100,000 Gauss. A magnetar's monster magnetic field is estimated to be as high as 1,000,000,000,000,000 Gauss. A magnet this strong, located at about half the distance to the Moon would easily erase your credit cards and suck pens out of your pocket. 

 Hubble has shown that hidden at the center of this galaxy are what seem to be disks of matter spiraling into a black hole with a billion times the mass of the Sun! Centaurus A itself is apparently the result of a collision of two galaxies and the left over debris is steadily being consumed by the black hole.

GRO J1655 40: Evidence for a Spinning Black Hole
In the center of a swirling whirlpool of hot gas is likely a beast that has never been seen directly: a black hole. Studies of the bright light emitted by the swirling gas frequently indicate not only that a black hole is present, but also likely attributes. The gas surrounding GRO J1655-40, for example, has been found to display an unusual flickering at a rate of 450 times a second. Given a previous mass estimate for the central object of seven times the mass of our Sun, the rate of the fast flickering can be explained by a black hole that is rotating very rapidly. What physical mechanisms actually cause the flickering -- and a slower quasi-periodic oscillation (QPO) -- in accretion disks surrounding black holes and neutron stars remains a topic of much research.

 Einstein didn't believe QM was a correct theory!) Even some chemists fall into that category-- to represent physical chemistry our departmental T-shirts have a picture of the below atom, which is almost a century out of date. <Sigh>
     So please read on, and take a dip in an ocean of information that I find completely invigorating!

).

What is the importance of quantum mechanics?

The following are among the most important things which quantum mechanics can describe while classical physics cannot:

• Discreteness of energy
• The wave-particle duality of light and matter
• Quantum tunneling
• The Heisenberg uncertainty principle
• Spin of a particle

Discreteness of energy

If you look at the spectrum of light emitted by energetic atoms (such as the orange-yellow light from sodium vapor street lights, or the blue-white light from mercury vapor lamps) you will notice that it is composed of individual lines of different colors. These lines represent the discrete energy levels of the electrons in those excited atoms. When an electron in a high energy state jumps down to a lower one, the atom emits a photon of light which corresponds to the exact energy difference of those two levels (conservation of energy). The bigger the energy difference, the more energetic the photon will be, and the closer its color will be to the violet end of the spectrum. If electrons were not restricted to discrete energy levels, the spectrum from an excited atom would be a continuous spread of colors from red to violet with no individual lines.

The concept of discrete energy levels can be demonstrated with a 3-way light bulb. A 40/75/115 watt bulb can only shine light at those three wattage's, and when you switch from one setting to the next, the power immediately jumps to the new setting instead of just gradually increasing.

It is the fact that electrons can only exist at discrete energy levels which prevents them from spiraling into the nucleus, as classical physics predicts. And it is this quantization of energy, along with some other atomic properties that are quantized, which gives quantum mechanics its name.

The wave-particle duality of light and matter

In 1690 Christiaan Huygens theorized that light was composed of waves, while in 1704 Isaac Newton explained that light was made of tiny particles. Experiments supported each of their theories. However, neither a completely-particle theory nor a completely-wave theory could explain all of the phenomena associated with light! So scientists began to think of light as both a particle and a wave. In 1923 Louis de Broglie hypothesized that a material particle could also exhibit wavelike properties, and in 1927 it was shown (by Davisson and Germer) that electrons can indeed behave like waves.

How can something be both a particle and a wave at the same time? For one thing, it is incorrect to think of light as a stream of particles moving up and down in a wavelike manner. Actually, light and matter exist as particles; what behaves like a wave is the probability of where that particle will be. The reason light sometimes appears to act as a wave is because we are noticing the accumulation of many of the light particles distributed over the probabilities of where each particle could be.

For instance, suppose we had a dart-throwing machine that had a 5% chance of hitting the bulls-eye and a 95% chance of hitting the outer ring and no chance of hitting any other place on the dart board. Now, suppose we let the machine throw 100 darts, keeping all of them stuck in the board. We can see each individual dart (so we know they behave like a particle) but we can also see a pattern on the board of a large ring of darts surrounding a small cluster in the middle. This pattern is the accumulation of the individual darts over the probabilities of where each dart could have landed, and represents the 'wavelike' behavior of the darts. Get it?

Quantum tunneling

This is one of the most interesting phenomena to arise from quantum mechanics; without it computer chips would not exist, and a 'personal' computer would probably take up an entire room. As stated above, a wave determines the probability of where a particle will be. When that probability wave encounters an energy barrier most of the wave will be reflected back, but a small portion of it will 'leak' into the barrier. If the barrier is small enough, the wave that leaked through will continue on the other side of it. Even though the particle doesn't have enough energy to get over the barrier, there is still a small probability that it can 'tunnel' through it!

Let's say you are throwing a rubber ball against a wall. You know you don't have enough energy to throw it through the wall, so you always expect it to bounce back. Quantum mechanics, however, says that there is a small probability that the ball could go right through the wall (without damaging the wall) and continue its flight on the other side! With something as large as a rubber ball, though, that probability is so small that you could throw the ball for billions of years and never see it go through the wall. But with something as tiny as an electron, tunneling is an everyday occurrence.

On the flip side of tunneling, when a particle encounters a drop in energy there is a small probability that it will be reflected. In other words, if you were rolling a marble off a flat level table, there is a small chance that when the marble reached the edge it would bounce back instead of dropping to the floor! Again, for something as large as a marble you'll probably never see something like that happen, but for photons (the massless particles of light) it is a very real occurrence.

The Heisenberg uncertainty principle

People are familiar with measuring things in the macroscopic world around them. Someone pulls out a tape measure and determines the length of a table. A state trooper aims his radar gun at a car and knows what direction the car is traveling, as well as how fast. They get the information they want and don't worry whether the measurement itself has changed what they were measuring. After all, what would be the sense in determining that a table is 80 cm long if the very act of measuring it changed its length!

At the atomic scale of quantum mechanics, however, measurement becomes a very delicate process. Let's say you want to find out where an electron is and where it is going (that trooper has a feeling that any electron he catches will be going faster than the local speed limit). How would you do it? Get a super high powered magnifier and look for it? The very act of looking depends upon light, which is made of photons, and these photons could have enough momentum that once they hit the electron they would change its course! It's like rolling the cue ball across a billiard table and trying to discover where it is going by bouncing the 8-ball off of it; by making the measurement with the 8-ball you have certainly altered the course of the cue ball. You may have discovered where the cue ball was, but now have no idea of where it is going (because you were measuring with the 8-ball instead of actually looking at the table).

Werner Heisenberg was the first to realize that certain pairs of measurements have an intrinsic uncertainty associated with them. For instance, if you have a very good idea of where something is located, then, to a certain degree, you must have a poor idea of how fast it is moving or in what direction. We don't notice this in everyday life because any inherent uncertainty from Heisenberg's principle is well within the acceptable accuracy we desire. For example, you may see a parked car and think you know exactly where it is and exactly how fast it is moving. But would you really know those things exactly? If you were to measure the position of the car to an accuracy of a billionth of a billionth of a centimeter, you would be trying to measure the positions of the individual atoms which make up the car, and those atoms would be jiggling around just because the temperature of the car was above absolute zero!

Heisenberg's uncertainty principle completely flies in the face of classical physics. After all, the very foundation of science is the ability to measure things accurately, and now quantum mechanics is saying that it's impossible to get those measurements exact! But the Heisenberg uncertainty principle is a fact of nature, and it would be impossible to build a measuring device which could get around it.

Spin of a particle

In 1922 Otto Stern and Walther Gerlach performed an experiment whose results could not be explained by classical physics. Their experiment indicated that atomic particles possess an intrinsic angular momentum, or spin, and that this spin is quantized (that is, it can only have certain discrete values). Spin is a completely quantum mechanical property of a particle and cannot be explained in any way by classical physics.

It is important to realize that the spin of an atomic particle is not a measure of how it is spinning! In fact, it is impossible to tell whether something as small as an electron is spinning at all! The word 'spin' is just a convenient way of talking about the intrinsic angular momentum of a particle.

Magnetic resonance imaging (MRI) uses the fact that under certain conditions the spin of hydrogen nuclei can be 'flipped' from one state to another. By measuring the location of these flips, a picture can be formed of where the hydrogen atoms (mainly as a part of water) are in a body. Since tumors tend to have a different water concentration from the surrounding tissue, they would stand out in such a picture.

What is the Schrödinger equation?

Every quantum particle is characterized by a wave function. In 1925 Erwin Schrödinger developed the differential equation which describes the evolution of those wave functions. By using Schrödinger's equation scientists can find the wave function which solves a particular problem in quantum mechanics. Unfortunately, it is usually impossible to find an exact solution to the equation, so certain assumptions are used in order to obtain an approximate answer for the particular problem.

As mentioned earlier, the Schrödinger equation for a particular problem cannot always be solved exactly. However, when there is no force acting upon a particle its potential energy is zero and the Schrödinger equation for the particle can be exactly solved. The solution to this 'free' particle is something known as a wave packet (which initially looks just like a Gaussian bell curve). Wave packets, therefore, can provide a useful way to find approximate solutions to problems which otherwise could not be easily solved.

First, a wave packet is assumed to initially describe the particle under study. Then, when the particle encounters a force (so its potential energy is no longer zero), that force modifies the wave packet. The trick, of course, is to find accurate (and quick!) ways to 'propagate' the wave packet so that it still represents the particle at a later point in time. Finding such propagation techniques, and applying them to useful problems, is the topic of my current research.

Currently there are two 'golden rules' of physics - General Relativity, which governs the large-scale Universe and quantum mechanics, which governs the nanoworld of atoms. The problem is that the two laws don't really agree with each other. What is needed to bridge the gap is an extra clause that links the two, a 'theory of everything', known as quantum gravity, that has yet to be discovered.

Superstring theory is a contender for this prize. The idea is that the zoo of thousands of tiny 'elementary' particles that exist are not disparate entities but all originate from the same source - a vibrating string. The easiest way to imagine this is to think of a guitar string. Pressing on the fretboard alters the length of the vibrating string, producing a new note. Similarly, in superstring theory, elementary particles can be thought of as different notes played on the same string. Each string is unimaginably small, about 10²⁰ (100 billion billion) times smaller than a proton. Vibrating the string at different frequencies generates all the different types of oddly-named elementary particles, such as 'gluons', 'weakons' and 'strange quarks'.

But in order to vibrate, strings need lots of room. In fact they need more room than is available in the four-dimensional world in which we live (made up of height, width, depth and time). Superstring theory requires the presence of ten dimensions! But where have the other six gone? Physicists have suggested that during the Big Bang these other dimensions were folded away, or 'compactified' leaving only four to expand and evolve.

But what does this mean for dark matter, the missing mass of the Universe? If superstring theory is right then it could provide an unusual answer to this cosmic mystery. Although these hidden dimensions remain too small to be measured, gravity can travel in between them. Hence the extra mass that is missing from our Universe may just be fallout from these unseen dimensions.

First we'll have to wait to see whether superstring theory is accepted as the crucial 'theory of everything'. If it is, then astronomers might have finally discovered where dark matter has been hiding out.

Short and Long Gamma-Ray Bursts Different to the Core

A new analysis of nearly 2,000 gamma-ray bursts -- the mysterious creators of black holes and the most powerful explosions known in the Universe -- has revealed that the two major varieties, long and short bursts, appear to arise from different types of events.

In an analysis of nearly 2,000 bursts, a team of researchers from Europe and Penn State University uncovered new discrepancies in the light patterns in bursts lasting less the two seconds and in bursts lasting longer than two seconds.

"We can now say with a high degree of statistical certainty that the two show a different physical behavior," said Lajos Balazs of Konkoly Observatory in Budapest, lead author on a paper appearing in an upcoming issue of the journal Astronomy & Astrophysics.

The analysis supports the growing consensus that long bursts originate from fantastic explosions of stars over 30 times more massive than our Sun. Short bursts have been variously hypothesized to be fiery mergers of neutron stars, black holes, or both, or perhaps a physically different type of behavior in massive collapses.

"It is suspected that, either way, with each gamma-ray burst we wind up with a brand new black hole," said Peter Meszaros, professor and head of the Penn State Department of Astronomy and Astrophysics. "The puzzle is in trying to identify clues that would help to elucidate whether these two types consist of essentially the same objects with different behaviors, or different objects with somewhat similar behavior."

Gamma-ray bursts are like a 10^45 watt bulb, over a million trillion times as bright as the Sun. Although common -- detectable at a rate of about one per day -- the bursts are fast-fading and random, never occurring in the same place twice. Scientists have been hard pressed to study the bursts in detail, for they last only a few milliseconds to about 100 seconds, with most around 10 seconds long. Most scientists agree that the majority of bursts originate in the distant reaches of the Universe, billions of light years away.

Previous results have shown that the short bursts have "harder" spectra, which means that they contain relatively more higher-energy gamma-ray photons than the longer bursts do. Also, in short bursts, the photons hitting a burst detector are closely spaced, or bunched, compared to the longer bursts, suggesting that the source is physically different, as well.

This type of information is valuable because it appears to contain clues about the intrinsic physical mechanism by which the sources produce the gamma rays, but these sources have still not been characterized in enough detail to understand them. Balazs and his colleagues sought to establish what, if any, correlation exists between different pairs of properties, when one considers separately the long and the short bursts.

The team examined the fluence and duration of 1,972 bursts and found a new relationship. The fluence is the total energy of all the photons emitted by the burst during its gamma-ray active stage, a measurement incorporating both the flow and energy of individual photons.

Within both categories, long and short, there is a correlation between fluence and duration: the longer the burst, the greater the fluence. Yet the degree of this relationship is statistically different for the two categories (at a 4.5 sigma significance level). This difference places constraints on what can cause these bursts or how they can operate.

In long bursts, there is a direct proportionality between duration and fluence, suggesting that the energy conversion rate into gamma rays is, on average, more or less constant in time. For the short bursts, there is a weaker dependence, which could, for instance, be due to an energy conversion rate into gamma rays that drops in time, resulting in a less efficient gamma-ray engine.

It seems unlikely that the same engine could produce both types of bursts, the team said. Although not directly addressed in the paper, these results support the notion that if the long bursts originate from massive stellar explosions, then short bursts originate from something entirely different. In the latter scenario, this event could be either mergers or such a drastic Jekyll-and-Hyde-like switch in the stellar explosion mode that the engine appears physically quite different. Such drastic and well-defined differences in the correlation between two of the major variables will need to be addressed quantitatively in future models of the burst physics.

The 1,972 bursts were observed by the BATSE instrument on the NASA Compton Gamma Ray Observatory, a mission active between 1991 and 2000. Coauthors also include Zsolt Bagoly, of the Laboratory for Information Technology at Eotvos University in Budapest; Istvan Horvath, of the Department of Physics at Bolyai Military University in Budapest; and Attila Meszaros, of the Astronomical Institute at Charles University in Prague.

Fermions are a class of particles that are inherently difficult to coax into a uniform quantum state. The ability to meld fermions into this state---a soup of particles that acts like one giant, super molecule---may lead to better understanding of superconductivity, in which electricity flows through certain metals with no resistance.

The work was described in a paper posted November 7 on the informal physics archival Web site at http://arxiv.org/ and will be published online by the journal Nature on November 26. Researchers Deborah S. Jin of NIST and Markus Greiner and Cindy A. Regal of CU-Boulder reported that they created a Bose-Einstein condensate (BEC) of weakly bound molecules starting with a gas of fermionic potassium atoms cooled to 150 nanoKelvin above absolute zero (about minus 273 degrees Celsius or minus 459 degrees Fahrenheit).

Jin describes her team's work as the "first molecular condensate" and says it is closely related to "fermionic superfluidity," a hotly sought after state in gases that is analogous to superconductivity in metals. "Fermionic superfluidity is superconductivity in another form," says Jin. Quantum physicists are in a worldwide race to produce fermionic superfluidity because gases would be much easier to study than solid superconductors and such work could lead to more useful superconducting materials.

While fermionic superfluidity was not demonstrated in the current experiments, the NIST/CU-Boulder authors note that their molecular condensate was produced by passing through the appropriate conditions for fermionic superfluidity.

A separate research group at the University of Innsbruck in Austria reported on November 13 in the online version of the journal Science that they had created a similar Bose-Einstein "super molecule" from lithium, fermion atoms.

Bose-Einstein condensates are a new form of matter first created by JILA scientists Eric Cornell of NIST and Carl Wieman of CU-Boulder in 1995 with rubidium atoms. The pair received the physics Nobel Prize in 2001 for the achievement. First predicted by Albert Einstein, BECs are an unusual physical state in which thousands of atoms behave as though they were a single entity with identical energies and wave forms. Consequently, BECs have been described as a magnifying glass for quantum physics, the basic laws that govern the behavior of all matter.

In the world of quantum physics, atomic particles are classified as either fermions (e.g., electrons, protons and neutrons) or bosons (e.g., photons) depending on their spin. Fermions have half-integer spins (1/2, 3/2, 5/2, etc.) and bosons have integer spins (0, 1, 2, 3, etc.). In addition, whereas no fermion can be in exactly the same state as another fermion, bosons have no such restrictions. Light waves or photons are the most commonly known bosons, and laser light is an example of how bosons can behave in unison.

Since 1995, dozens of research groups worldwide have created BECs and several thousand scientific papers have been published on the subject. Recently, a number of groups have been working to produce a condensate from fermions. Superconductivity occurs when electrons (a type of fermion) combine into pairs. By producing pairing of ultracold fermionic atoms in a reproducible fashion, researchers hope to explore the physics underlying the "super" phenomena in unprecedented detail.

In their experiment, the JILA scientists paired up individual fermion atoms (with half-integer spins) into molecules (with integer spins) and in doing so formed a Bose-Einstein condensate. The researchers cooled a gas of potassium atoms (potassium isotope 40) with lasers and confined them in an optical trap. They then slowly varied the strength of a magnetic field applied across the trap to increase the attraction between pairs of atoms and eventually converted most of the fermionic atoms into bosonic molecules.

"Strikingly," they said, the molecular condensate was not formed by further cooling of the molecules but solely by the increased attractive forces created with the magnetic field. When the initial temperature of the fermion atoms was sufficiently low, the gas collapsed into the BEC as soon as the loosely bound bosonic molecules formed.

Funding for the research was provided by NIST, the National Science Foundation and the Hertz Foundation.

In October 2003, Jin received a $500,000 John D. and Catherine T. MacArthur Fellowship, often referred to as a "genius grant."

Recent reports by U.S. and European researchers have hinted at connections between the presence of methane and other gases in Mars’ atmosphere and the possibility of water-harboring subsurface caves capable of sustaining life.

The theory is similar to actual conditions found in deep caverns on Earth, such as the Lechuguilla cave in New Mexico - the deepest found in the continental U.S. - where hardy bacteria thrive in a pool of water and feed off gases. Below the surface of Idaho, creatures dubbed methanogens give off methane as waste while subsisting on hydrogen from rocks around underground springs.

The meaning of methane

But whether some form of life once existed, or currently lives, in Martian caves is still unknown.

In March 2004, a trio of independent studies using Mars Express and ground telescopes announced the detection of methane in Mars’ atmosphere. Months later, in September, the European Space Agency (ESA) released Mars Express data detailing an overlap of methane and water vapor concentrations.

Researchers stressed that a skeptical eye is required after news reports stating that some scientists had linked the presence of Mars methane to the possibility that microbial life may generating the gas as a byproduct of subsisting off underground caches of water.

"The fact that you find methane does not mean you have to have life," Tobias Owen, a University of Hawaii astronomer who was part of a team that detected Mars methane with ground-based telescopes, told reporters at a recent science symposium. "You have to be very careful."

Flatland?

A skull-scorching theory is gaining support among physicists that the universe is nothing more than an elaborate two-dimensional place with only the illusion of three. Proponents of this holographic principle believe that all of the complexities of reality contain far less information than common sense would suggest.

Think of the universe as a computer program. Programs contain information coded in sets of ones and zeros. The universe also contains information coded with the direction, speed and positive or negative charges of subatomic particles. The everyday world is an expression of the information in those particles.

Light from a star that exploded some ten thousand light-years away first reached our fair planet in the year 1181. Now known as supernova remnant 3C58, the region glows in x-rays, powered by a rapidly spinning neutron star or pulsar - the dense remains of the collapsed stellar core. A cosmic dynamo with more mass than the sun yet smaller than Chicago, the pulsar's electromagnetic fields seem to accelerate particles to enormous energies, creating the jets, rings, and loop structures. While adding 3C58 to the list of pulsar powered nebulae explored with Chandra, astronomers have deduced that the pulsar itself is much too cool for its tender years, citing 3C5 8 as a show case of extreme physics not well understood. The remnant spans about six light-years.

What is string theory?

String theory is at this moment the most promising candidate theory for a unified description of the fundamental particles and forces in nature including gravity. As a theory of quantum gravity string theory is at present our best hope to give concretely computable answers to fundamental questions such as the underlying symmetries of nature, the quantum behaviour of black holes, the existence and breaking of supersymmetry, and the quantum treatment of singularities. It might also shed light upon larger issues such as the nature of quantum mechanics and space and time. In string theory all the forces and particles emerge in an elegant geometrical way, realizing Einstein's dream of building everything from the geometry of space-time.

String theory is based on the (deceptively simple) premise that at Planckian scales, where the quantum effects of gravity are strong, particles are actually one-dimensional extended objects. Just as a particle that moves through spacetime sweeps out a curve (the worldline)

Astronomers have recently confirmed that "dark matter" represents 23% of the energy in our universe (and visible matter only 4%). We do not know the nature of dark matter, except that it does not interact with light, and is therefore not visible. But it's distribution in the universe has been mapped by looking for the gravitational effects on visible matter. HNI was hired by the University of Syracuse to make a holographic image of a computer simulation of this dark matter distribution, calculated by evolving the conditions shorty after the Big Bang through 13 billion years, to the current conditions today. The computations were performed by Michael S. Warren at Los Alamos National Laboratory, and prepared especially for the holographic rendering. The resulting image shows a cubic volume of our universe, 300 million light years on a side, and closely resembles the corresponding observational results.

An early attempt to explain the concept of extra dimensions came in 1884 with the publication of Edwin A. Abbott's Flatland: A Romance of Many Dimensions. This novel is a "first-person" account of a two-dimensional square who comes to appreciate a three-dimensional world.The square describes his world as a plane populated by lines, circles, squares, triangles, and pentagons. Being two-dimensional, the inhabitants of Flatland appear as lines to one another. They discern one another's shape both by touching and by seeing how the lines appear to change in length as the inhabitants move around one another.One day, a sphere appears before the square. To the square, which can see only a slice of the sphere, the shape before him is that of a two-dimensional circle. The sphere has visited the square intent on making the square understand the three-dimensional world that he, the sphere, belongs to. He explains the notions of "above" and "below," which the square confuses with "forward" and "back." When the sphere passes through the plane of Flatland to show how he can move in three dimensions, the square sees only that the line he'd been observing gets shorter and shorter and then disappears. No matter what the sphere says or does, the square cannot comprehend a space other than the two-dimensional world that he knows.

For most of us, or perhaps all of us, it's impossible to imagine a world consisting of more than three spatial dimensions. Are we correct when we intuit that such a world couldn't exist? Or is it that our brains are simply incapable of imagining additional dimensions—dimensions that may turn out to be as real as other things we can't detect? String theorists are betting that extra dimensions do indeed exist; in fact, the equations that describe superstring theory require a universe with no fewer than 10 dimensions. But even physicists who spend all day thinking about extra spatial dimensions have a hard time describing what they might look like or how we apparently feeble-minded humans might approach an understanding of them. That's always been the case, and perhaps always will be

singularity is a region of space-time in which gravitational forces are so strong that even general relativity, the well-proven gravitational theory of Einstein, and the best theory we have for describing the structure of the universe, breaks down there. A singularity marks a point where the curvature of space-time is infinite, or, in other words, it possesses zero volume and infinite density. General relativity demands that singularities arise under two circumstances. First, a singularity must form during the creation of a black hole. When a very massive star reaches the end of its life, its core, which was previously held up by the pressure of the nuclear fusion that was taking place, collapses and all the matter in the core gets crushed out of existence at the singularity. Second, general relativity shows that under certain reasonable assumptions, an expanding universe like ours must have begun as a singularity.

Observations reveal that vast halos of invisible matter surround galaxies and galaxy clusters. This dark matter adds up to about ten times more mass than the visible stars, gas, and dust seen in galaxies. And there may be more. The inflationary theory, if true, demands that this dark stuff makes up between 90 and 99% of the universe. Astronomers have yet to determine what constitutes this dark matter, although some leading candidates go by the names MACHOs, WIMPs, and neutrinos.

 Computer-simulated universes are a very powerful tool because they allow you to produce material evidence for what various assumptions about the universe translate into, and then you can take this material evidence and compare it against reality. Because the universe is so complex, most mathematical treatments require many approximations and simplifications, so they are of limited applicability. Yet with a computer simulation you don’t need to make any of those approximations.  You solve the equations in the full generality, so it's a very appealing activity for theoreticians to do. In the classic Einsteinian view of the universe, everything is smooth at the beginning and stays smooth forever. That clearly is not what our universe is doing because today our universe is very inhomogeneous—it is broken up into islands that we call galaxies and galaxy clusters. If the universe had been entirely smooth, we wouldn’t be here to talk about it.

Accretion Disk Simulation

Explanation: Don't be fooled by the familiar pattern. The graceful spiral structure seen in this computer visualization does not portray winding spiral arms in a distant galaxy of stars. Instead, the graphic shows spiral shock waves in a three dimensional simulation of an accretion disk -- material swirling onto a compact central object that could represent a white dwarf star, neutron star, or black hole. Such accretion disks power bright x-ray sources within our own galaxy. They form in binary star systems which consist of a donor star (not shown above), supplying the accreting material, and a compact object whose strong gravity ultimately draws the material towards its surface. For known x-ray binary systems the size of the accretion disk itself might fall somewhere between the diameter of the Sun (about 1,400,000 kilometers) and the diameter of the Moon's orbit (800,000 kilometers). One interesting result of the virtual reality astrophysics illustrated here is that the simulated disk develops instabilities which tend to smear out the pronounced spiral shocks

Our innate perception that the world is three-dimensional could be an extraordinary illusion.

Hawking's radiation process allowed him to determine the proportionality constant between black hole entropy and horizon area: black hole entropy is precisely one quarter of the event horizon's area measured in Planck areas. (The Planck length, about 10-33 centimeter, is the fundamental length scale related to gravity and quantum mechanics. The Planck area is its square.) Even in thermodynamic terms, this is a vast quantity of entropy. The entropy of a black hole one centimeter in diameter would be about 1066 bits, roughly equal to the thermodynamic entropy of a cube of water 10 billion kilometers on a side.

The World as a Hologram

The GSL allows us to set bounds on the information capacity of any isolated physical system, limits that refer to the information at all levels of structure down to level X. In 1980 I began studying the first such bound, called the universal entropy bound, which limits how much entropy can be carried by a specified mass of a specified size [see box on opposite page]. A related idea, the holographic bound, was devised in 1995 by Leonard Susskind of Stanford University. It limits how much entropy can be contained in matter and energy occupying a specified volume of space.

In his work on the holographic bound, Susskind considered any approximately spherical isolated mass that is not itself a black hole and that fits inside a closed surface of area A. If the mass can collapse to a black hole, that hole will end up with a horizon area smaller than A. The black hole entropy is therefore smaller than A/4. According to the GSL, the entropy of the system cannot decrease, so the mass's original entropy cannot have been bigger than A/4. It follows that the entropy of an isolated physical system with boundary area A is necessarily less than A/4. What if the mass does not spontaneously collapse? In 2000 I showed that a tiny black hole can be used to convert the system to a black hole not much different from the one in Susskind's argument. The bound is therefore independent of the constitution of the system or of the nature of level X. It just depends on the GSL.

We can now answer some of those elusive questions about the ultimate limits of information storage. A device measuring a centimeter across could in principle hold up to 1066 bits--a mind-boggling amount. The visible universe contains at least 10100 bits of entropy, which could in principle be packed inside a sphere a tenth of a light-year across. Estimating the entropy of the universe is a difficult problem, however, and much larger numbers, requiring a sphere almost as big as the universe itself, are entirely plausible.

But it is another aspect of the holographic bound that is truly astonishing. Namely, that the maximum possible entropy depends on the boundary area instead of the volume. Imagine that we are piling up computer memory chips in a big heap. The number of transistors--the total data storage capacity--increases with the volume of the heap. So, too, does the total thermodynamic entropy of all the chips. Remarkably, though, the theoretical ultimate information capacity of the space occupied by the heap increases only with the surface area. Because volume increases more rapidly than surface area, at some point the entropy of all the chips would exceed the holographic bound. It would seem that either the GSL or our commonsense ideas of entropy and information capacity must fail. In fact, what fails is the pile itself: it would collapse under its own gravity and form a black hole before that impasse was reached. Thereafter each additional memory chip would increase the mass and surface area of the black hole in a way that would continue to preserve the GSL.

This surprising result--that information capacity depends on surface area--has a natural explanation if the holographic principle (proposed in 1993 by Nobelist Gerard 't Hooft of the University of Utrecht in the Netherlands and elaborated by Susskind) is true. In the everyday world, a hologram is a special kind of photograph that generates a full three-dimensional image when it is illuminated in the right manner. All the information describing the 3-D scene is encoded into the pattern of light and dark areas on the two-dimensional piece of film, ready to be regenerated. The holographic principle contends that an analogue of this visual magic applies to the full physical description of any system occupying a 3-D region: it proposes that another physical theory defined only on the 2-D boundary of the region completely describes the 3-D physics. If a 3-D system can be fully described by a physical theory operating solely on its 2-D boundary, one would expect the information content of the system not to exceed that of the description on the boundary.

A Universe Painted on Its Boundary

Can we apply the holographic principle to the universe at large? The real universe is a 4-D system: it has volume and extends in time. If the physics of our universe is holographic, there would be an alternative set of physical laws, operating on a 3-D boundary of spacetime somewhere, that would be equivalent to our known 4-D physics. We do not yet know of any such 3-D theory that works in that way. Indeed, what surface should we use as the boundary of the universe? One step toward realizing these ideas is to study models that are simpler than our real universe.

A class of concrete examples of the holographic principle at work involves so-called anti-de Sitter spacetimes. The original de Sitter spacetime is a model universe first obtained by Dutch astronomer Willem de Sitter in 1917 as a solution of Einstein's equations, including the repulsive force known as the cosmological constant. De Sitter's spacetime is empty, expands at an accelerating rate and is very highly symmetrical. In 1997 astronomers studying distant supernova explosions concluded that our universe now expands in an accelerated fashion and will probably become increasingly like a de Sitter spacetime in the future. Now, if the repulsion in Einstein's equations is changed to attraction, de Sitter's solution turns into the anti-de Sitter spacetime, which has equally as much symmetry. More important for the holographic concept, it possesses a boundary, which is located "at infinity" and is a lot like our everyday spacetime.

Using anti-de Sitter spacetime, theorists have devised a concrete example of the holographic principle at work: a universe described by superstring theory functioning in an anti-de Sitter spacetime is completely equivalent to a quantum field theory operating on the boundary of that spacetime [see box above]. Thus, the full majesty of superstring theory in an anti-de Sitter universe is painted on the boundary of the universe. Juan Maldacena, then at Harvard University, first conjectured such a relation in 1997 for the 5-D anti-de Sitter case, and it was later confirmed for many situations by Edward Witten of the Institute for Advanced Study in Princeton, N.J., and Steven S. Gubser, Igor R. Klebanov and Alexander M. Polyakov of Princeton University. Examples of this holographic correspondence are now known for spacetimes with a variety of dimensions.

This result means that two ostensibly very different theories--not even acting in spaces of the same dimension--are equivalent. Creatures living in one of these universes would be incapable of determining if they inhabited a 5-D universe described by string theory or a 4-D one described by a quantum field theory of point particles. (Of course, the structures of their brains might give them an overwhelming "commonsense" prejudice in favor of one description or another, in just the way that our brains construct an innate perception that our universe has three spatial dimensions; see the illustration on the opposite page.)

The holographic equivalence can allow a difficult calculation in the 4-D boundary spacetime, such as the behavior of quarks and gluons, to be traded for another, easier calculation in the highly symmetric, 5-D anti-de Sitter spacetime. The correspondence works the other way, too. Witten has shown that a black hole in anti-de Sitter spacetime corresponds to hot radiation in the alternative physics operating on the bounding spacetime. The entropy of the hole--a deeply mysterious concept--equals the radiation's entropy, which is quite mundane.

The Expanding Universe

Highly symmetric and empty, the 5-D anti-de Sitter universe is hardly like our universe existing in 4-D, filled with matter and radiation, and riddled with violent events. Even if we approximate our real universe with one that has matter and radiation spread uniformly throughout, we get not an anti-de Sitter universe but rather a "Friedmann-Robertson-Walker" universe. Most cosmologists today concur that our universe resembles an FRW universe, one that is infinite, has no boundary and will go on expanding ad infinitum.

Does such a universe conform to the holographic principle or the holographic bound? Susskind's argument based on collapse to a black hole is of no help here. Indeed, the holographic bound deduced from black holes must break down in a uniform expanding universe. The entropy of a region uniformly filled with matter and radiation is truly proportional to its volume. A sufficiently large region will therefore violate the holographic bound.

In 1999 Raphael Bousso, then at Stanford, proposed a modified holographic bound, which has since been found to work even in situations where the bounds we discussed earlier cannot be applied. Bousso's formulation starts with any suitable 2-D surface; it may be closed like a sphere or open like a sheet of paper. One then imagines a brief burst of light issuing simultaneously and perpendicularly from all over one side of the surface. The only demand is that the imaginary light rays are converging to start with. Light emitted from the inner surface of a spherical shell, for instance, satisfies that requirement. One then considers the entropy of the matter and radiation that these imaginary rays traverse, up to the points where they start crossing. Bousso conjectured that this entropy cannot exceed the entropy represented by the initial surface--one quarter of its area, measured in Planck areas. This is a different way of tallying up the entropy than that used in the original holographic bound. Bousso's bound refers not to the entropy of a region at one time but rather to the sum of entropies of locales at a variety of times: those that are "illuminated" by the light burst from the surface.

Bousso's bound subsumes other entropy bounds while avoiding their limitations. Both the universal entropy bound and the 't Hooft-Susskind form of the holographic bound can be deduced from Bousso's for any isolated system that is not evolving rapidly and whose gravitational field is not strong. When these conditions are overstepped--as for a collapsing sphere of matter already inside a black hole--these bounds eventually fail, whereas Bousso's bound continues to hold. Bousso has also shown that his strategy can be used to locate the 2-D surfaces on which holograms of the world can be set up.

Researchers have proposed many other entropy bounds. The proliferation of variations on the holographic motif makes it clear that the subject has not yet reached the status of physical law. But although the holographic way of thinking is not yet fully understood, it seems to be here to stay. And with it comes a realization that the fundamental belief, prevalent for 50 years, that field theory is the ultimate language of physics must give way. Fields, such as the electromagnetic field, vary continuously from point to point, and they thereby describe an infinity of degrees of freedom. Superstring theory also embraces an infinite number of degrees of freedom. Holography restricts the number of degrees of freedom that can be present inside a bounding surface to a finite number; field theory with its infinity cannot be the final story. Furthermore, even if the infinity is tamed, the mysterious dependence of information on surface area must be somehow accommodated.

Holography may be a guide to a better theory. What is the fundamental theory like? The chain of reasoning involving holography suggests to some, notably Lee Smolin of the Perimeter Institute for Theoretical Physics in Waterloo, that such a final theory must be concerned not with fields, not even with spacetime, but rather with information exchange among physical processes. If so, the vision of information as the stuff the world is made of will have found a worthy embodiment.

NGC 1531/2: Interacting Galaxies

Explanation: This dramatic image of an interacting pair of galaxies was made using 8-meter Gemini South telescope at Cerro Pachon, Chile. NGC 1531 is the background galaxy with a bright core just above center and NGC 1532 is the foreground spiral galaxy laced with dust lanes. The pair is about 55 million light-years away in the southern constellation Eridanus. These galaxies lie close enough together so that each feels the influence of the other's gravity. The gravitational tug-of-war has triggered star formation in the foreground spiral as evidenced by the young, bright blue star clusters along the upper edge of the front spiral arm. Though the spiral galaxy in this pair is viewed nearly edge-on, astronomers believe the system is similar to the face-on spiral and companion known as M51, the Whirlpool Galaxy.

By introducing Supersymmetry to Bosonic String Theory, we can obtain a new theory that describes both the forces and the matter which make up the Universe. This is the theory of superstrings. There are three different superstring theories which make sense, i.e. display no mathematical inconsistencies. In two of them the fundamental object is a closed string, while in the third, open strings are the building blocks. Furthermore, mixing the best features of the bosonic string and the superstring, we can create two other consistent theories of strings, Heterotic String Theories.

However, this abundance of theories of strings was a puzzle: If we are searching for the theory of everything, to have five of them is an embarrassment of riches! Fortunately, M-theory came to save us.

Extra dimensions...M-theory

 A Higher Dimensional Universe  Does our universe have higher but unusual spatial dimensions? This idea has been gaining popularity to help explain why vastly separated parts of our universe appear so similar, and why the geometry of our universe does not seem to result naturally from the amounts of matter it seems to contain. In a new incarnation of an old extra-dimensional idea, some astrophysicists hypothesize that we live in a universe dubbed Ekpyrotic, where our four dimensions (three spatial plus one time) resulted from the fiery collision of two four-dimensional spaces (branes) in a five-dimensional universe. This big-bang hypothesis is meant to compete with another big-bang hypothesis that our universe underwent a superluminal inflation event in the distant past, and does make distinct testable predictions. Above, a dynamic three-dimensional drawing (two spatial plus one time) of a four-dimensional depiction of a five-dimensional cube (a hypercube with four spatial dimensions is also known as a tesseract) is shown. Donning red-blue glasses will give the best multi-dimensional perspective. Apart from the fact that instead of one there are five different, healthy theories of strings (three superstrings and two heterotic strings) there was another difficulty in studying these theories: we did not have tools to explore the theory over all possible values of the parameters in the theory. Each theory was like a large planet of which we only knew a small island somewhere on the planet. But over the last four years, techniques were developed to explore the theories more thoroughly, in other words, to travel around the seas in each of those planets and find new islands. And only then it was realized that those five string theories are actually islands on the same planet, not different ones! Thus there is an underlying theory of which all string theories are only different aspects. This was called M-theory. The M might stand for Mother of all theories or Mystery, because the planet we call M-theory is still largely unexplored. momentum = the mass of a particle multiplied by its velocity

elementary particles, through quantum effects communicate faster than light

the observer can never really be separated from the observation as an elementary particle really doesn’t exist unless it is observed. Bell’s Theorem can be stated most succinctly in his own words; "Reality is non-local”.  

M theory and gamma ray bursts!

 Magnetar Throws Giant Flare 

Explanation: Was the brightest Galactic blast yet recorded a key to connecting two types of celestial explosions? Last December, a dense sheet of gamma rays only a few times wider than the Earth plowed through our Solar System, saturating satellites and noticeably reflecting off the Moon. A magnetar near our Galactic Center, the source of Soft Gamma Repeater (SGR) 1806-20, had unleashed its largest flare on record. The brightness and briefness of the tremendous explosion's initial peak made it look quite similar to another type of tremendous explosion if viewed from further away -- a short duration gamma-ray burst (GRB). Short duration GRBs are thought by many to be fundamentally different than their long duration GRB cousins that are likely related to distant supernovas. Illustrated above is a series of drawings depicting an outgoing explosion during the initial SGR spike. A fast moving wave of radiation is pictured shooting away from a central magnetar. The possible link between SGRs and GRBs should become better understood as more and similar events are detected by the Earth-orbiting Swift satellite.

Reality is non-local”.                  by Mike Milne     

M theory and gamma ray bursts

 by Mike Milne                                                 Level: Spaceweather

Aerogel is not like conventional foams, but is a special porous material with extreme microporosity on a micron scale. It is composed of individual features only a few nanometers in size. These are linked in a highly porous dendritic-like structure.

This exotic substance has many unusual properties, such as low thermal conductivity, refractive index
                                    and sound speed - in addition to its exceptional ability to capture fast moving dust. Aerogel is made by high temperature
                                    and pressure-critical-point drying of a gel composed of colloidal silica structural units filled with solvents. Aerogel was
                                    prepared and flight qualified at the Jet Propulsion Laboratory (JPL). JPL also produced aerogel for the Mars Pathfinder and
                                    Stardust missions, which possesses well-controlled properties and purity. This particular JPL-made silica aerogel approaches
                                    the density of air

 M theory and gamma ray bursts

         by Mike Milne                                                  

  laws of the universe

M theory  communicate faster than light gamma ray bursts

                       T         …blackholes

 missing mass problem Reality is non-local”.     by Mike Milne

 Interstellar spaceflight is a term used to describe the use of hypothetical spacecraft that would be capable of journeying from the solar system, across interstellar space and to another star.The concept of interstellar spaceflight is common in science fiction and has been explored in many theoretically oriented design studies. Interstellar spacecraft able to make journeys in years (rather than in many millennia) are from feasible with current propulsion technologies. Among the approaches that have been given serious, quantitative analysis are propulsion by nuclear fusion, matter/antimatter rockets, and sails driven by radiation pressure from beams emitted by large laser or microwave arrays. To reach other stars in times of decades or less would require speeds that are a substantial fraction of the speed of light. An such speeds, the interstellar medium of gas and dust presents hazards requiring effective shielding to prevent destruction of the craft.Some scientists have speculated that a viable way of crossing vast interstellar distances may be through the use of wormholes, but no means of creating or stabilizing such wormholes has been proposed that does not invoke unknown physics. In the realm of science fiction, engines capable of moving faster than the speed of light are often mentioned as the means to cross interstellar distances. Hyperdrive and warp drive are two names applied to "FTL" (faster than light) devices. However, the geometry of space-time is such that FTL travel (as seen by one observer) is travel backward in time (as seen by other observers), and that a suitable round-trip journey would result in travel backward in time (as seen by all observers). Thus, the concept of FTL travel is inseparable from the concept of time travel. No concrete, physical means for achieving either has survived scrutiny by physicists.A potentially easier approach would be to use a maser to drive a "solar sail" composed of a mesh of wires with the same spacing as the wavelength of the microwaves, since the manipulation of microwave radiation is somewhat easier than the manipulation of visible light. The hypothetical "Starwisp" interstellar probe design would use a microwave laser to drive it. Microwave lasers spread out more rapidly than optical lasers thanks to their longer wavelength, and so would not have as long an effective range.Microwave lasers could also be used to power a painted solar sail, a conventional sail coated with a layer of chemicals designed to evaporate when struck by microwave radiation. The momentum generated by this evaporation could significantly increase the thrust generated by solar sails.To further focus the energy on a distant solar sail, designs have considered the use of a large zone plate. This would be placed at a location between the laser or maser and the spacecraft. The plate could then be propelled outward using the same energy source, thus maintaining its position so as to focus the energy on the solar sail.Spacecraft fitted with solar sails can also be placed in close orbits about the Sun that are stationary with respect to either the Sun or the Earth, a type of satellite called a statite. This is possible because the propulsion provided by the sail offsets the gravitational potential of the Sun. Such an orbit could be useful for studying the properties of the Sun over long durations.Such a spacecraft could conceivably be placed directly over a pole of the Sun, and remain at that station for lengthy durations. Likewise a solar sail-equipped spacecraft could also remain on station nearly above the polar terminator of a planet such as the Earth by tilting the sail at the appropriate angle needed to just counteract the planet's gravity.Future Visions Despite the loss of Cosmos 1 (which was due to a failure of the launcher), most scientists and engineers around the world remain undiscouraged and continue to work on solar sails. While most direct applications created so far intend to use the sails as inexpensive modes of cargo transport, some scientists are investigating the possibility of using solar sails as a means of transporting humans. This goal is strongly related to the management of very large (i.e. well above 1 km²) surfaces in space and the sail making advancements. Thus, in the near/medium term, solar sail propulsion is aimed chiefly at accomplishing a very high number of non-crewed missions in any part of the solar system and beyondThere are two types of wormholes that may enable interstellar travel. The first kind originates with the same process as a black hole: the death of a star. Wormholes of this kind safe enough for a human being to navigate would probably have to be supermassive and rotating, on a similar scale to Sagittarius A* at the centre of the Milky Way Galaxy; smaller black holes produce intense tidal forces that would completely destroy anybody falling into them. Theorists postulate that wormholes connect arbitrary points in -- or between -- universes, across an Einstein-Rosen Bridge.Another kind of wormhole is based on quantum gravity. Some have speculated that Euclidean wormholes that spontaneously come into being and disappear again, and exist at scales of Planck length. It may be that this wormhole could be "propped open" using negative energy (also known as vacuum energy), though the quantity of the energy would be immense. However, it is not clear that any of this is possible, largely because there is no widely accepted theory of quantum gravity.A third idea involves starships that utilize Alcubierre's warp drive. In this theory, a starship warps space, expanding space behind it and contracting space ahead of it. The concept of manipulating space-time in this manner is based on Einstein's General Theory of Relativity, but would require the existence of negative-mass materials, which are neither observed nor predicted by current physical theory.Light-speed interstellar travelThe fastest possible travel is at light-speed, which can be achieved by sending photons (or other massless particles that might be shown to exist). This is equivalent to communication using any part of the electromagnetic spectrum.It may not be practical or even feasible to transport a massive organism (i.e. one that contains mass) across interstellar distances, but it is within the realms of physical possibility to transmit enough information that the organism could be reconstructed at the receiving end. It may even be sufficient to send software that in all practical purposes duplicates the neural function of the organism, rather than sending an atom by atom description of the entire body.It is conceivable that at our present technology, humankind would be able to implement (after suitable translation) such software on our present day computational hardware. This is possible and maybe even probable when one considers that all classical computing devices are all in some sense equivalent Turing Machines.NASA researchAs part of the NASA Breakthrough Propulsion Physics Project, it identified three things which must happen, or breakthroughs which are needed, in order for interstellar travel to be possible A new propulsion method which has less need for propellant A method of propulsion which is able to reach the maximum speed which is possible to attain A new method of on board energy production method which would power those devices. The authors find 13 good candidates for nearby ‘biostars’ with three ranking especially high: HD 1581 (Zeta Tucanae), HD 109358 (Beta Comae Berenicis) and HD 115617 (61 Virginis): “We suggest these objects as high priority targets in SETI surveys and in future space interferometric missions aiming at detecting life by the ozone atmospheric infrared biosignature of telluric planets.” Future research should weigh more detailed models of planetary climate stability and (relatedly) a possible reassessment of M-class stars if tenable ecosystems seem to be allowed. And Centauri Dreams strongly seconds the paper’s emphasis on more intense study of galactic orbits, which may be the largest constraint of all on habi  how fast did inflation occur? In a space of time lasting about 10^-35 seconds, the universe could have expanded by a factor of 10³⁰ to 10¹⁰⁰. As Brian Greene puts it in The Fabric of the Cosmos:An expansion factor of 10³⁰ — a conservative estimate — would be like scaling up a molecule of DNA to roughly the size of the Milky Way galaxy, and in a time interval that’s much shorter than a billionth of a billionth of a billionth of the blink of an eye… In the many models of inflation in which the calculated expansion factor is much larger than 10³⁰, the resulting spatial expanse is so enormous that the region we are able to see, even with the most powerful telescope possible, is but a tiny fraction of the whole universe   while General Relativity is valid, there are several approaches within it that may permit bypassing the speed of light limit (even if any civilizations that could build them might have to be more advanced than ours by millions of years):  The use of wormholes, engineered through the use of exotic matter. The mathematical requirements for creating a traversable wormhole have entered the scientific literature in the works of, among others, Kip Thorne.  The Alcubierre warp drive concept, which notes that there is no limit to the speed at which space itself might stretch. Faster than light relative motion is built into inflation theory. Alcubierre’s work shows that a spacecraft could theoretically make use of expanding spacetime behind and a similar contraction in front of the vehicle to overcome the restrictions of General Relativity.  Superstring theory suggests the possiblity that adjacent universes could be all around us. The added dimensionalities of M-brane and superstring theory might allow a sufficiently advanced technology to move into an adjcent universe where the speed of light limit is different than our own. a technology to cohere otherwise random vacuum fluctuations. Nonetheless, the possibility of reduced-time interstellar travel by advanced extraterrestrial (ET) civilizations is not, as naive consideration might hold, fundamentally ruled out by presently known physical principles. ET knowledge of the physical universe may comprise new principles which allow some form of FTL travel. This possibility is to be taken seriously, since the average age of suitable stars within the ‘galactic habitable zone’ in which the Earth also resides, is found to be about 10⁹ years older than the Sun Is the answer to the Fermi paradox, then, that we are even now being visited by extraterrestrial spacecraft whose contact strategy is based on a sense of interstellar ethics we do not yet understand? The paper argues that such visitations must be considered more likely than a ‘we are alone’ answer to the Fermi question, and goes on to consider what ethical considerations might motivate a culture investigating our planet from outside Earth. The paper is Deardorff, Haisch, Maccabee and Puthoff, “Inflation-Theory Implications for Extraterrestrial Visitation,” in the Journal of the British Interplanetary Society Vol. 58, No. 1/2 (January/February 2005Now change the perspective again. Suppose this time it’s the Earth that is the size of a period on a printed page (which is, by the way, about 0.5 mm). On that scale, the Sun would be a little smaller than a tennis ball at a distance of some 5.9 meters (19 feet). The Alpha Centauri A and B stars would lie roughly 890 miles away. Now think about this one: the parallax of Proxima Centauri, the M-class red dwarf that apparently orbits Centauri A and B at about 10,000 AU, is about equivalent to that of a dime at a distance of 6 kilometers. Proxima is so faint that astronomers on a planet orbiting either Centauri A or B would probably not realize it was nearby until they took measurements of its own parallax. GSU provides a helpful backgrounder on parallax, noting its use in measuring the distance to the few stars that are close enough to the Sun to show a measurable parallax. The limit of this measurement is about 20 parsecs, which includes some 2000 stars.  

missing mass problem

Scientists using different methods to determine the mass of galaxies have found a discrepancy that suggests ninety percent of the universe is matter in a form that cannot be seen. Some scientists think dark matter is in the form of massive objects, such as black holes, that hang out around galaxies unseen. Other scientists believe dark matter to be subatomic particles that rarely interact with ordinary matter. This paper is a review of current literature. I look at how scientists have determined the mass discrepancy, what they think dark matter is and how they are looking for it, and how dark matter fits into current theories about the origin and the fate of the universe. MACHOs are made of 'ordinary' matter, which is called baryonic matter. WIMPs, on the other hand, are the little weak subatomic dark matter candidates, which are thought to be made of stuff other than ordinary matter, called non-baryonic matter. Astronomers search for MACHOs and particle physicists look for WIMPs.most scientists concede that dark matter is a combination of baryonic MACHOs and non-baryonic WIMPs.

We believe that most of the matter in the universe is dark, i.e. cannot be detected from the light which it emits (or fails to emit). This is "stuff" which cannot be seen directly -- so what makes us think that it exists at all? Its presence is inferred indirectly from the motions of astronomical objects, specifically stellar, galactic, and galaxy cluster/supercluster observations. It is also required in order to enable gravity to amplify the small fluctuations in the Cosmic Microwave Background enough to form the large-scale structures that we see in the universe today.

SuitSat's transmissions are much weaker than expected. If you wish to listen, you'll need a ham radio tuned to 145.990 MHz and a high-gain antenna to receive the signals

Right: A blood sample from an ISS astronaut that has been damaged by space radiation. The strands are chromosomes "painted" with florescent dye. "The picture shows big pieces of different colors stuck together," notes Cucinotta. "These are places where broken DNA has been repaired incorrectly by the cell."

When I was a graduate student, for my thesis I studied quantum field theory in curved space-time – a topic that is on the boundary between quantum theory and the General Theory of Relativity. It was hoped – it still is hoped – that one day these two theories will be unified. Logically, they are in deep conflict with each other, and this conflict is not within the reach of present day experiments to resolve. We know that a unification isn’t going to be easy. That unified theory would be called quantum gravity. The reason for studying quantum field theory in curved space-time was that it was hoped that when we understood that well, it would provide a clue to quantum gravity. We did eventually understand it well, and it did not provide a clue to quantum gravity. But it did convince me that quantum theory is at present the deeper of the two, and also, for the moment at any rate, provides more promising lines of research. Peter Medawar said once that science is the art of the soluble. You cannot necessarily solve the most profound problems right away. You have to go for the most profound soluble problem. And in that respect, I thought that quantum theory was the more promising.

So you now believe that quantum mechanics will provide a unifying theory of the universe?

‘Provide’ is not quite the right word. Quantum theory will be a pathway, a component of some future more unifying theory which will involve among other things the General Theory of Relativity. But also I think it will involve areas which are now not even considered part of physics. Certain areas of epistemology, certain parts of philosophy and mathematics, and the theory of evolution will also be part of the new unifying theory, of which we do have glimpses but which has not yet been formulated.

Quantum mechanics is very complex. And there are still unresolved areas. Do you think the mystery of it may be resolved, say, within 20 years or so? Or is that too optimistic?

One hears a lot about the ‘mysteries’ of quantum mechanics but I do not think that there are any. Although there are still open areas of research within quantum mechanics I do not think that they are fundamental mysteries provided that one adopts the many-worlds interpretation of quantum physics. There are mysteries in physics, principally the unification of quantum theory with General Relativity. We really have only clues at the moment, and I would be rash to predict that this would be solved in the next 20 years, although this is one of those areas where the solution could come at any time. And then there would be a frantic rush to work out its meaning. Even that frantic rush might take decades. So, I do not know.

How will this theory help to explain man’s existence in the world?

Again, we don’t know yet. We only have some tantalising clues. It seems likely to me that the 400 year old consensus in science that human beings are insignificant in the fundamental scheme of things in the universe has to break down. It is not that we know what the true role of humans is. It is that the arguments that humans don’t have a fundamental role in the scheme of things, which used to seem so self-evidently true, have all fallen away. I mean, it is no longer true that human beings are necessarily destined to have a negligible effect on physical events, because there is the possibility that humans will spread and colonize the galaxy. If they do, they will necessarily have to affect its physical constitution in some ways. It is no longer true that the fundamental quantities of nature – forces, energies, pressures – are independent of anything that humans do, because the creation of knowledge (or ‘adaptation’ or ‘evolution’ and so on) now has to be understood as one of the fundamental processes in nature; that is, they are fundamental in the sense that one needs to understand them in order to understand the universe in a fundamental way. So, in this and other ways, ‘human’ quantities – human considerations, human affairs and so on – are fundamental after all. But we do not yet understand the details of how they fit in with the more familiar fundamental processes that we know about from physics.