INTRODUCTON
It was Fritz Zwicky, (1898-1974), who eighty years ago (in 1933 and 1937), studying the internal motions of the Virgo and Coma Clusters of galaxies, on the assumption that stars were the repository of most mass in the universe, and light would naturally trace that mass, found that deduced masses were much larger than could be accounted for by the light of the stellar populations. He found that the massive galactic clusters, some 320 million light years away, were moving relative to each other in a way that was inconsistent with their inferred masses. He accounted for all the mass that he could see in visible light, but there still was an enormous amount- "about four hundred times more --of missing mass," (Bell p. 288) than what he could see. In his remarkable papers, largely ignored for several decades, the problem of the "missing mass" (Dickey p. 20) was discussed and called "dark matter," matter that you could not see, but the observations demanded must be there. But the hunt was started.
MACS JO717 - A MASSIVE GALAXY CLUSTER
Cosmic theories and observations now conclude that the universe within the confines of the limits of the finite dimensions of the Big Bang, is made up of a web of filaments that connect at the locations of massive galaxy clusters. These structures are made of DARK MATTER, that elusive substance that is extremely difficult to observe because it doesn't emit or reflect any light. Using a phenomenon called "gravitational lensing" which distorts light that passes close to a massive object, astronomers detected one such filament for the first time in early 2012, then a team went further by studying another filament's structure in 3-D. The results indicate that dark matter extends out from MACS JO717.5+3745, one of the most massive galaxy clusters known. To create a map of the region, the team led by Mathilde Jauzac of the Laboratoire of d'Astrophysique de Marseille in France, started with the high resolution images from the Hubble Space Telescope, which can detect the effects of gravitational lensing. The group then combined these observations with photos of the region from ground-based instruments and data on cluster members from the KECK and GEMINI OBSERVATORIES. The resultant 3-D map shows that the filament extends from MACS JO717 some million light-years in a direction back away from the cluster core from Earth's view point. If the mass of the dark matter that makes up this structure is indicative of similar filaments, then these pieces of the cosmic web make up more than half of the mass of the entire universe. (Ferron p. 16) But what is this ubiquitous, unseen, material they call dark matter, stuff that we simply don't, as yet, understand? (Bell p. 288) Is it a matter of you cannot see it, but yet know it must be there? (Ruben in Denielson p. 81)
The world's most sensitive dark-matter experiment submitted its first results on October 30. It reported no sign of the elusive substance. Astronomical observations have been pointing to the presence of dark matter in space, but attempts to detect it directly passing through Earth, if it in fact it can do so, produced conflicting results. The findings were derived from a 110 day search at the LARGE UNDERGROUND XENON EXPERIMENT (LUXE) in Lead, South Dakota. It did not confirm three earlier experiments that had reported hints of dark matter particles. (Nature 11, Vol. 503, page 11, 7 November 2013.) They don't know what it is yet, but it is there. The hunt goes on. It may be a matter of elimination.
NEW GALAXY SURVEY FOR DARK ENERGY
A massive sky-mapping project to study dark energy was announced by FERMILAB in Batavia, Illinois, on 3 September 2013. This Dark Energy Survey at the CERRO TOLOLO INTER-AMERICAN OBSERVATORY in Chile was launched on 31 August 2013. Over the next five years, it will map 300 million galaxies covering one-eighth of the night sky at different distances. The data from its 570-megapixel camera may lead to a better understanding of the mysterious dark-energy, if there is such a thing, that is thought to drive the Universe's accelerating expansion. Expansion has occurred, how and when, is part of the reason for the search. (Nature Vol. 501, page 140, 12 September 2013) There are serious theorists working on an alternate expansion explanation. Much of the distances in space between present galaxies and all stars, even our separation from local or nearest stars, is a result of billions of years of expansion. We used to have a lot of neighbors, and they were very friendly, but we have lost most of them by vast distances.
The past quarter of a century has been an extraordinarily lively time for cosmology. It was the proposal in the early 1980's of the theory of accelerated inflation that provided solutions to some of the outstanding cosmological puzzles leading to an understanding of the mechanism for the origin of large scale structures, which could be tested by observations of the anisotropies (irregularities) in the COSMIC MICROWAVE BACKGROUND (CMB), briefly discussed in earlier parts of this series. Details were, in part, published in the proceedings of a lecture series held at the University of Minnesota in the spring quarter of 1988 on the subject of clusters of galaxies and large scale structure of the universe, anticipating the great galactic surveys of twenty years later. (Dickey p. i) This was all part of programs, or conference series, of the Astronomical Society of the Pacific. They were anticipating much of what is being found and learned today about the cosmos, but they succeeded very well in identifying more questions that need to be answered.
PURSUING THE BLACK HOLE
By the early 1990's, most astronomers suspected bazaar objects called black holes did not even exist. Confirmation was hard to come by. Skeptics like to say that extraordinary claims require extraordinary proof, and things don' get much more astonishing than black holes. These bodies, from small to large, possess a gravitational pull so powerful that nothing, not even light, can escape their clutches. Information about what happens inside a black hole can never leave it. Matter in a black hole's vicinity suffers conspicuously from the intense gravity wayward stars move abnormally fast, and gas becomes superheated and radiates copious amounts of light. Astronomers confirm a black hole's existence when they see these signatures and can eliminate all other possible causes.
Just in the past fifteen years or so up to late 2012, the tally of black holes in our own galaxy had reached 19. Of these, 18 are now known to reside in x-ray-emitting binary star systems, and one, the big one, lurks in the center of the Milky Way's core. (Talcott p. 44) With new instruments the count now is up to 52, and astronomers are reaching out still. But these are just the larger ones.
In the late 1700's British professor John Mitchell and French astronomer and mathematician Pierre--Simon Laplace advanced the idea of what Laplace called "dark bodies." Using Newton's concepts of light and gravity, they reasoned that the gravitational pull of a massive star could be large enough to prevent light from escaping. But Newton's theory could not describe what happens when gravity grows that strong. It would nearly two hundred years before flesh could be put to the idea. That understanding would come when Einstein developed his general theory of relativity. Relativity, which treats gravity as a distortion of space-time, (that needs to be explained) a concept many find it hard to get their head around, also physicists describe black holes in gory detail. But it would still take decades before most scientists considered these objects more than theoretical curiosities. This was more than fifty years before the reality of black holes began to emerge once astronomers understood how massive stars die. If a star begins life with more than about eight times the sun's mass, it will not experience a quiet death. When such a star exhausts its nuclear fuel, its core collapses. This triggers a shock wave that destroys the rest of the star in a brilliant massive explosion, a supernova, that can shine with the light of 10 billion Suns. The supernova create super cosmological nucleosynthesis. (Arnett p. 118) In most cases the core left behind weighs between l.4 to 3 solar masses and has been crushed into a sphere the size of a major city. A single teaspoonful of this so called neutron star would weigh close to a trillion tons. (Talcott p. 46) But that does not make a black hole as much gravity as the neutron star obtains by its actions. This exotic end state pales in comparison with what happens to the rarest of stars that start life with more than 30 solar masses, condensing from a supper massive cloud of matter. In 1939, physicists J. Robert Oppenheimer and Hartland Snyder showed that when such a star dies, it's collapsed core, weighing more than three Suns, is too heavy to settle down as a neutron star. It creates a region of space-time cut off from the rest of the universe because no light can ever escape. Thirty years later, the physicist John Wheeler coined the descriptive term black holes for these objects. (Danielson p. 371)
Black holes now are known to possess at least three characteristics: mass, spin, and charge All other properties of the collapsing star are lost. Such stars rarely have any excess positive or negative charge, therefore, mass and spin and its affect on nearby matter, dust or stars, describe most black holes.
A key feature of the black hole is its "event horizon"-the radius at which a beam of light would fail to escape. Any event that takes place within this horizon can never be glimpsed from outside. For a non-spinning, 20-solar mass black hole, the event horizon spans approximately 17 miles. Double the mass, and the diameter also doubles. A black hole spinning at the maximum possible rate has a diameter half that of a non-rotating one with the same mass. So, now we know the limits.
Huge supernovae of type l-b become unstable due to nuclear activities in their mass and implode, or collapse. These objects weighing millions even billion of times as much as the Sun lie at the heart of nearly all galaxies. Now, it is difficult to say that a galaxy does not have a black hole present. New instruments and new images are stripping the matter from these spheres of warped space so we learn what is really there.
EVENT HORIZON TELESCOPE (EHT)
So across the universe as we're learning to know it, there are trillions of black holes. These objects are so compact that their gravitational pull prevents anything from escaping, even light. They blaze brilliantly as giant stars before collapsing catastrophically. Others, far more massive and ancient sit at the center of galaxies, including our own. When they draw in material from their surroundings, such monster black holes can shoot out jets of energetic particles that stretch for hundreds of thousands of light-years. One of this kind is in the galaxy Hercules A, which resides in the irregular Hercules Cluster of galaxies that looks like a meandering river of galaxies seven hundred million light years away from earth. It is one of four associated clusters that make up the Hercules Supercluster that stretches out for a length of fifty million years. (Ferris p. 150)
The black hole in Hercules A is representative of many similar black holes. Recall that theoretical predictions of the existence of black holes date back more than a century to Albert Einstein's general theory of relativity that built on his earlier publications. Karl Schwartzchild, one of Einstein's' colleagues in 1915, interpreted the relativity equations and showed that a sufficiently massive object could curve space and time in on itself, isolating itself off from the rest of the universe. Even Einstein had a hard time imaging such a possibility. It took another half-century before scientists started accepting that black holes exist, and only recently have they grasped the full cosmological importance of these extreme objects.
By definition black holes cannot emit any visible light, so those concerned with cosmological themes are forced to study them indirectly, or use new instruments that detect radiation other than visible light. Much of our knowledge comes from observing gas as it is pulled into or ejected from the black hole. What cosmologists really want to know is what is happening right at what they call the EVENT HORIZON, the outer boundary that defines a black hole's point of no return. That is the goal of the EVENT HORIZON TELESCOPE (EHT), which links together radio antennas around the world to create, in effect a new larger telescope the size of the Earth. Even in its preliminary form it can resolve details as small as 60 micro-arc-seconds, equivalent to seeing a baseball on the surface of the moon. Eventually new instruments will do better than that, until then, they reach as far as they can, into that awesome delirium of immensity. And they make spectacular discoveries.
This past year new equipment in several areas has become employed in the serious hunt for the largest BLACK HOLE. The immense super-galaxy, M87, with its supermassive black hole, was discussed in PART 6, p. 2, as was the large black hole at the center of our galaxy. In earlier Parts of this series, the great galaxy surveys were also briefly mentioned. Now the work is isolating individual galaxies in the hunt for the first galaxies that were formed, and the hunt for the largest black holes, so specific studies can be made to understand their character in detail
This coming year will be particularly exciting for studying black holes. In our own galaxy there is a cloud of gas nearing the massive back hole, SAGITTARIUS A*, a strong interaction is expected. Using the EVENT HORIZON TELESCOPE, (EHT) and other instruments, astronomers will be able to see directly how a black hole gets fed. The cloud of gas is on its immediate menu. A dozen years or so ago, it was hard to convince skeptics that black holes were even real. Now it is known that in some essential way, they are among the essential building blocks of the universe. SAGITTARUS A* is an oddly quiescent beast. Stars orbit around it but not much matter reaches the black hole itself. It is so subdued that it is almost always invisible in optical images or x-ray maps of the center of our galaxy. Astronomers only became aware of Sagittarius A* in 1974 from radio emissions. There are nearly two dozen stars and gas clouds in the vicinity or orbiting the black hole in different unrelated orbits. Especially being monitored is STAR SO-2 where part of its orbit bring it dangerously close to a capture point, so far it has eluded the gravity seduction of the black hole, but the black hole is patient, sooner or later STAR SO-2 will be put on the menu. (Melia pp. 40-42) STAR SO-102 is another star that is orbiting the black hole and like SO-2 a part of its orbit gets very close to the black hole. The gas cloud G2, was recognized in 2003 and has been tracked for the past ten years as it has spiraled closer and closer to its destiny with the Black hole. The gas cloud has about the mass of our solar system. It is headed straight for the black hole. The cloud doubled its velocity in just eight years and is now being pulled out in an elongate form involved in the vicinity of ten stars for which projections of their positions and what remains of the gas cloud have been made through 2021. (American Scientist, p. 123, March-April 2012) Melia and others have been tracking stars and their orbits for nearly 20 years and have positions of the Stars in most aspects of their orbits. The motion of the stars reveal they are orbiting around a compact object that weighs more than 4.3 million solar masses. Only a black hole could invisibly contain so much matter in such a small space. Einstein's equations of relativity indicate that SAGITTARIUS A* has an event horizon (Melia p. 129), 25 million kilometers across. Its formation was probably intertwined with the birth of our galaxy, the more modest black holes began their lives as bright stars but then exploded and collapsed. When matter gets close to one of the STELLAR mass black holes, it settles into a flattened formation called an accretion disk spinning around the black hole. The extreme gravity near the black hole then causes the gas to heat up tens of millions of degrees Celsius and emit x-rays. That gives it away. Features around the black holes (See ANATOMY OF A BLACK HOLE IMAGE ) have been identified and include the accretion disc made up of matter that have been drawn in by the black hole and drawn out in such a manner that it forms a flattened disc spinning ever closer towards the black hole. They can determine in some instances the direction the accretion disc is spinning. By a shift in the wavelengths of light, or spectral lines, that occurs when it is going away or coming toward you, they can determine spin. Some black holes have absorbed the close available matter and do not for the time being have a spinning accumulating accretion disc. That portion of the spinning accretion disc that is nearer the black hole becomes a hot spot and emits x-rays that are detectable, one of the signature aspects of a black hole. At the point where matter falls into the black hole, matter is also ejected, forming the jets seen in some black hole. Not all black holes have jets which form at the point of singularity. With details yet to be determined, in some black holes energy had accumulated and there are laser like jets that spew out particles from the center, the jets are moving particles moving at more than 66 % of the speed of light, perpendicular in both directions, to the accretion disk. The jet can convey a lot of matter into space creating the features found in a number of black holes of massive plumes of matter taking on shapes that vary with the black hole and its jets. (Larrondo pp. 451-452)
If the black hole has a nearby companions star, the star can get shredded and slowly consumed, creating a brilliant x-ray beacon. More than 50 such systems that have identified and are being studied with varying degrees of detail. One of these systems is called XTE J1550-564. It turns out to share basic traits with other far more massive active black holes. As noted, many active black holes shoot off supersonic jets of particles above and below the accretion disk which may extend many light years outside of the home galaxy. The jets produce copious amounts of radio emission so they can be detected by Radio Telescopes, because they contain high-speed particles and strong magnetic fields, when you combine the two you get synchrotron radiation, charged particles that are accelerated in the presence of a magnetic field, whose intensity peaks at radio frequencies and therefore are detectable. But, exactly, how the jets are produced, or even what they are made of, remains a mystery. So they are the focus of intensive study. (Larrondo p.453)
SUPPERMASSIVE BLACK HOLES
The nearest active supermassive black hole resides in CENTAURUS A, a galaxy less than 13 million light-years away just five times farther than our neighboring Andromeda galaxy in our local group. The dynamics of the gas and stars near the central regions reveal that this black hole weights 50 million solar masses, more than 10 times as massive as our SAGITARIUS A*. In visible light, CENTARUS A looks like a roundish galaxy with an unusual dust lane going through its center. When examined in radio waves instead of light, however, something different is seen: two powerful jets shooting out from the center. X-rays detected from Centaurus A provides yet another perspective. Emerging from the black hole are spectacular jets perpendicular to the plane of the spin of the galaxy that light up the galaxy, and more important, at the center there is a bright point-like x-ray source, which coincides with the location of the supermassive black hole. A combined view of the two types of images detected shows beautifully all of the components together, the impressive bright center and two great feathery like plumes modified by what seems to be a spin to the feature as the ends of the plumes are deformed as if the entire object is spinning and the end of the jets appear to be dragged with the leading edges lagging and appearing stretched out. What is astounding is that the black hole is almost a billion times smaller than the galaxy, yet produces jets that extend way past the visible edge of the galaxy Centarus A. The images ask more questions than they answer. What is at the beginning ends of the jets? How do they form, what speed are they traveling, What are the particles that compose the jets? The new detectors and equipment are seeking answers to such questions.
M87 A GIANT ELLIPTICAL GALAXY
More clues about a supermassive black hole comes from M87, a giant elliptical galaxy 50 million light-years away. When one thinks of the time galaxies began to form some 13.5 billion lights years ago, M87 is close by, as are other massive black holes, so they are being studied in detail so an understanding of what will be and is being observed in the distant past. M87 is at the center of the nearby super-galaxy cluster of Virgo. M87 looks fairly normal, but it contains one of the most massive black holes known, with a mass nearly five billion times that of the sun. That is about a fifth of the mass of our entire galaxy which has about the mass of 2.3 trillion solar masses. The black hole in M87 is highly active and violent, as observed in dramatic composite images of radio emissions in the red and x-rays in blue, there seems to have been multiple jets almost surrounding the galaxy with ejected matter. There are even gigantic mushroom like clouds, recalling nuclear explosions. (Larrondo p. 454-455)
Larger galaxies systematically have more massive central black holes. The more massive the black holes, the larger is the event horizon. Interestingly, the "size" of a black hole scales directly with its mass. Double its mass, and its radius doubles as well. Astronomers made this interesting discovery more than 20 years ago. Now with new instruments they are fleshing out the details. The event horizon of M87's black hole is as large as our entire solar system. Because M87 harbors one of the most massive black holes known and it is relatively nearby, the apparent size of its black hole is just large enough that the EVENT HORIZON TELESCOPE has been able to image the base of the jet. The only other black hole that appears larger in the sky is our own black hole Sagittarius A* The most recent studies indicate that the jet in M87, which extends far beyond the edge of the host galaxy, originates from a region no larger than six time the size of the black hole!
SUPPER JETS
Astronomers developed the first radio telescopes in the 1930's. They discovered a number of bright radio sources in the sky, one very strong source was in the constellation of Cygnus (the Swan). Modern radio images show that Cygnus A is actually a pair of huge glowing "lobes" of matter with a fairly unremarkable looking galaxy between them. Cygnus A is now known to be a classic example of a "radio galaxy" -an active galaxy in which the nucleus region is edge on to the earth, and only the radio glow created by the escaping jets reveals anything unusual. It is one of the largest objects in the sky, with an overall diameter of half a million light years. The KECK 11 TELESCOPE on Mauna Kea, Hawaii, reveals the galaxy between the twin lobes of Cygnus A as a misshapen blaze of light with increasing brightness levels from dark blue through to red and yellow, with the brightest spots of all "burnt out" in black. It is hard to interpret the structure, but thick dust lanes running across the center suggests that it is in fact the merger of two galaxies that has sparked one of the central black holes into life. (Sparrow p. 119)
THE BIGGEST BLACK HOLES
More than 20 years ago, astronomers made a fascinating discovery mentioned above. The more massive the galaxy the more massive its central black hole. Now, the biggest galaxies lie at the centers of clusters of galaxies. M87 lies in the midst of billions of stars in a giant elliptical galaxy, and they can with their jets and gravity influence the home galaxy and affect not just their own galaxy but galaxies nearby and in the cluster as a whole as M87 does.
In the neighborhood of the Milky Way, there are two elliptical galaxies, M32 and M110, two small satellites of the Andromeda Galaxy 2.5 million light years away but part of the local group of galaxies. (Bergh p. 280, 287) But outside our local group there are larger elliptical balls of stars, some of which can match the scale of our own spiral galaxy, and some of which dwarf it. Giant ellipticals are enormous spherical star clouds with up to 200 times the mass of the Milky Way, they are the largest galaxies known. The nearest such galaxy to earth is Messier 87 mentioned earlier, it is around 55 million light years away at the heart of the Virgo galaxy cluster. (Sparrow p. 117)
There is a large grouping of galaxies called the Perseus Cluster, 350 Million light years distant, about one-fifth of the x-ray output is generated by a single galaxy, NGC1275, in the cluster. The cluster is three million light years in diameter. (Ferris p. 150) Such clusters contain large amounts of gas between their galaxies and because the cluster is so massive, the gas gets compressed and heated enough to glow when imaged and viewed with an x-ray detector. An x-ray image of the Perseus Cluster shows a lot of structure in a violet light. There is a central bright point source-which coincides with the supermassive black hole of the clusters dominant central galaxy NGC1275 (The NGC numbers are another system of cataloging), but there are also peculiar bubbles. Then an image is obtained of the white light features of the black hole area which produces a lot of features not seen in the x-ray picture. Next the black hole is imaged with radio wave detectors providing a pink image. The violet image from x-rays is nearly five times the size of the image provided by the size of the white light image. The dark bubbles of the violet masked are largely filled with bright emissions detected by the radio waves. The composite image is very beautiful and shows many more features for study than the old white light pictures provided. What is realized from the variety of detectors used to examine any object in space is the immense power black holes can have on their surrounding medium, influencing the evolution of galaxies and entire clusters of galaxies. (Larrondo p. 456)
Another galaxy cluster, known as MS 0735.6+7421, for short reference (21). From this number the system developed by observers of vast galactic surveys permits observers to locate the cluster in the immensity of our universe. It is located 2.8 million light years away. It shows features on an even larger scale. The bubbles in 21 are more than 10 times the size of the bubbles in the Perseus Cluster. Their size points to the presence of an ultramassive black hole in the central galaxy. About 10 years ago astronomers discovered a new way to find out. No matter the mass of a black hole, if it is accreting at low rates, its ratio of x-ray to radio emission depends solely on its mass. This discovery means that supermassive black holes are simply scaled-up versions of stellar-mass ones. By measuring its radiation ratio, astronomers estimate that the black holes in 21, and in many other similar clusters of galaxies, most weigh up to several tens of billions of solar masses. These are the most massive black holes in the universe. (Larrondo p. 456) Julie Hlavacek-Larrondo is an Einstein postdoctoral fellow at Stanford University: she moved in 2013 to University de Montreal to join the faculty in the department of physics. Her primary study is supermasive black holes, how they interact with their surroundings, and all else she can learn about them, with the tools and instruments recently made available and others in the pipeline. She no doubt will author a lot of material we will access in the future.
DISCOVERY OF A NEW BLACK HOLE IN OUR GALAXY
In October 2011, the scientists with NASA'S SWIFT SATELLITE (NSS) spotted an x-ray outburst on September 16, 2011, demonstrating the discovery of another black hole within our galaxy. They say gas from a Sun like star had accumulated in a disk of matter around the black hole for decades before suddenly, caught finally by the gravity of the black hole, and plunging toward the previously unknown dense object. (Astronomy p. 16, February 2013) Any star l.5 times larger, or much larger, than our sun, can implode and collapse in such a way as to result in a black hole, an object with all the characteristics of a larger black hole. One of NASA'S spacecraft has found thousands of small black hole candidates in the Milky Way, but there are probably many more. The nearest one to earth is only 1600 light years away. None of them match the size of the monster in the center of the galaxy. (Aguilar p. 114) Since you can't see them it is only when you are caught that you know you have one, and he isn't going to let you go.
Our Black Hole, Sagittarius A*, emits suspiciously few x-rays, since it is 4 million times the mass of the Sun it should be devouring gas, heating the material and causing it to radiate high-energy photons as it swirls in-ward. Puzzled by how little infrared and x-ray radiation they see, the CHANDRA X-RAY OBSERVATORY, looked in on the subject, and found clues about the black hole's quiescence, publishing the data in the August 30, 2013 issue of Science. CHANDRA'S images of the galactic center show that more than 99 % of the gas that could fall into the black hole avoids that fate. Sagittarius A* ejects this vast majority of approaching material away from the galactic core, the meal is too hot for it to digest. Cooler material, though, has less energy and is easier for Sagittarius to grab. By rejecting most of what comes its way the black hole causes what's left to lose momentum, cool down, and stop resisting being captured. Sera Markoff of the University of Amsterdam, says "We're watching Sagittarius A* capture hot gas ejected by nearby stars and funnel it in towards its event horizon." More precisely they are able to watch the unlucky one percent take this irreversible journey. (Astronomy December 2013 p. 11)
THE GAS CLOUD, G2, AND THE MILKY WAY'S BLACK HOLE
In July 2013 the G2, the cloud of dust being pulled into the black hole of the Milky Way, began to be shredded violently which lit up the galaxy's center, giving astronomers a chance to peer inside the galactic center and the neighborhood around the black hole. "What a difference it is when you can watch!" says G2's co-discoverer Stefan Gillessen, a scientist at the Max Planck Institute for Extraterrestrial Physics in Germany. As the gas cloud, G2, swung by the black hole's EVENT HORIZON, the point past which even light cannot escape, gravity stretched its leading edge into a ribbon 90 billion miles long, pulling it away from the tail, which isn't yet feeling the black hole's full effects. As gravity continues to tear G2 apart, its gas will become hotter than the sun's surface and its dust hotter than molten lead. These high temperatures and the black hole's extreme magnetic field will excite G2's component particles, causing them to radiate and bathe the mysterious region in VISIBLE LIGHT, X-RAYS, and RADIO WAVES. (Sarah Scoles p. 46, Discover Magazine, January-February 2014) Instruments that detect all three of these emissions are observing every detail of the encounter. G2's light show illuminates, not only our hometown singularity, but also help in understanding similar ones throughout the BIG BANG universe; shedding light, that future observations will detect. Knowing the kinds of emissions, their intensity and characteristics, will permit the detection and evaluation of events that are similar in the cosmos.
THE BIRTH OF GALAXIES
Many astronomers and many of the new instruments going on stream and planned for the future, are working on the answer to when were galxies formed? As data accumulates, most if not all galaxies contain old population 11 stars and therefore have ages of 8 or more billion years, the oldest they expect to find cannot be much older than about 13.4 billion years. The universe is now too old to form new galaxies, because the present intergalactic medium--the gas spread out between galaxies-is too low in density to give birth to them. As a rule of thumb the average density of matter in a galaxy such as our own Milky Way is l hydrogen atom per cubic centimeter. This would be the density if all stars were dissolved into a dispersed gas. Very roughly this is a million times greater than the average density of matter now in the universe. Because of the on-going expansion of the universe and it has been expanding ever since the beginning, about 13.82 billion years ago. This means that in the past the universe was denser, and the galaxies were crowded closer together. Expansion has separated everything.
Five billion years ago our solar system was born. The cluster of galaxies were close together and the average density of the universe was about four times its present value. Very much earlier, when the average density was a million times greater than now, the galaxies did not exist in their present form. If the universe was more dense the galaxies would be crushed together beyond recognition. The galaxies therefore originated in their present form when the expanding universe had an average age density of less than l hydrogen atom per cubic centimeter. This means that the galaxies originated when the universe had an age much greater than10 billion years. Theories are vague here. Great effort is being expended in trying to get a handle on why and how galaxies formed. Things had to cool enough for particles to form and then cluster, and then re-cluster as clouds, then clustered as stars, and re-clustered again as proto-galaxies, and finally as full blown galaxies. The theorists call this "fragmentation," (Harrison pp. 59-69) but do not know the reason for it, though clearly gravity played an immense early role.
EARLIEST KNOWN GALAXY - A STAR MAKER
Sinse the news release on the early galaxy, discussed below, another fuzzy irregular shaped, galaxy may have been found that may only be 450 million years after the BB.
A long time ago and far, far away, some kind of energy concentration suddenly was triggered in a massive explosion, they have called it the BIG BANG for decades, sometimes in derision, but gradually is has turned into the object of extreme attention and motivation of many astronomers and construction of billions of dollars of equipment to find out what happened. It may be outside the realm of science to say why it happened, Mormons have their views and they rely on certain elements of knowledge going back to at least 1830. PART I of this series outlines the themes that permitted anticipation of what is now being found. So it now appears that five hundred millions of years after the spectacular event of the BB, and perhaps there is no superlative to describe it, the Universe was full of galaxies. What happened in between the Big Bang and the appearance of extremely diverse features in the universe among them the collections of stars and elements we call galaxies?
In October a team reported a giant step into the exploration of that early time INTERVAL. With the equipment now available they imaged one of the earliest galaxy up to their time, dating from just 700 years after the BB. It is aglow with hot, newborn stars. The rate of star formation is estimated to be a hundred times that of the modern MILKY WAY. The find will provide a glimpse of an unexpected period of frenetic star birth in the early universe, at least of what is inside the Bubble of energy and matter we call the BB. What is outside and where the Bubble is in relationship to whatever else is OUT THERE, is now the subject of varying theories, mostly just fancy, but all of them will get credit for trying. Without a knowledge of the gospel and the restoration they will not get a correct answer.
The galaxy was just one of dozens imaged by a special HST survey designed to pick up faint, distant galaxies. Their reddish color suggested they are remote enough for the expansion of the universe to stretch and redden their light. Astronomers need to study a galaxy's spectrum to determine its precise distance from Earth.
Steven Finkelstein, and astronomer at the University of Texas, led the survey. He looked at a sample of these galaxies through a new spectrograph installed on one of the two 10 meter KECK telescopes at Mauna Kea, Hawaii. The new instrument called the MULTI-OBJECT SPECTROMETER FOR INFRARED EXPLORATION, (MOSIRE) can analyze light from 45 objects simultaneously. Traditional spectrographs look at only one object at a time. Studying 43 of the galaxies over two nights of observation, Finkelstein and his tem detected a new-infrared emission line from one of the galaxies, from which they measured a red shift of 7.81; a measure of how much light waves have been stretched by cosmic expansion. That meant the galaxy was 13.l billion light-years away, in a universe, at least for the time being, 13.82 billion years old. It also means it had already formed by 13,370 million years ago. We are most interested in the first 450 million years after TIME ZERO (T-0) , and how everything, now extant, was formed.
Because the galaxy was much brighter than distant galaxies typically are, Finkelstein and his team could make some inferences about it from its image and its spectrum. For one, the galaxy seems to be significantly rich in "metals"-- elements heavier than hydrogen and helium which were created by the BIG BANG. No more hydrogen (not a single proton) is being created now. Nothing in the present universe can create anymore hydrogen. Hydrogen in stars is being nuclearly fused into Helium, using up the protons that are available. The amount of Hydrogen generated initially determines this universe, limits it in every way. Its outcome is predetermined. In time there will be no more stars as we know them, with the hydrogen consumed, the stars will become helium stars, and in time they too will fuse their helium into heavier elements. Theorists are trying to assimilate what this all means realizing this BBB, or present universe, will change drastically and eventually by processes now known to become a dispersed immense cloud of particles or just energy. Our universe is finite. It has a beginning, it will have an end. The starting point is now called "T-O", the starting time, the zero moment. Whatever is before that remains to be identified.
Because all elements other than hydrogen, originate from fusion reactions in the heart of stars and are spewed out when those stars explode as supernovae, the relatively high metallicity of the galaxy suggests that it had already seen the birth and death of generations of stars by the time the universe was 450 to 700 million years old.
Finkelstein and his team also inferred from its brightness that the galaxy was forming stars at a rate of 330 solar masses per year. Generally other galaxies nearly as distant typically form stars at a rate no higher than 20 to 30 solar masses per year. So Volker Bromm, a theoretical astrophysicist at UT Austin who was not a part of the Finkelstein team, says the finding could mark a period in the cosmic timeline when galaxies weren't forming relatively new stars to when they were bursting with star formation. But this may suggest an early "cosmic bottleneck" that limits the efficiency of star formation. He says "when a galaxy is sufficiently enriched with "metals" [elements heavier than hydrogen and helium]- which help gas clouds coalesce more easily into stars-the star formation rate accelerates considerably." (Yudhijit Bhattacharjee p. 411)
Others say the models the researchers relied on to estimate star formation rates might not work well for such far- off galaxies. But the star formation rate would still be higher than fainter galaxies at the red shift determined. A lot of star formation is taking place, so further observations will be needed order to confirm the original conclusions. More observations will be made, other equipment used, and perhaps it can be resolved with the instruments available, if not, those observations planned for in the immediate and distant future will be making their contribution.
On August l, 2013, the HIGH-ALTITUDE WATER CERENKOV GAMMA-RAY OBSERVATORY, (HAWCGO), in Pueblo, Mexico, began searching for the highest-energy light in the cosmos. (Astronomy, December 2013, p. 11) And what happened at a time near T-0.
DARK ENERGY SURVEY
Where will they be looking for black holes in the future? A massive sky-mapping project to study dark energy began 31 August 2013, and was announced September 3, 2013. The DARK ENERGY SURVEY at the CERRO TOLOLO INTER-AMERICAN OBSERVATORY, involving the Fermilab in Batavia, Illinois. Over the next five years, the survey will map 300 million galaxies covering one-eighth of the night sky. Data from its 570-megapixsel CAMERA, may lead to a better understanding of the mysterious dark energy that is thought to drive the Universe's accelerating expansion. All look forward to the exciting results that will be obtained.
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