Our universe extends staggeringly far beyond our own earthly environment. Trying to grasp the size in any meaningful way is bound to make your brain hurt. We can make analogies to at least understand a few of the relevant scales, but this can’t give us a complete picture all in one go. In the end, we must settle for an understanding of large numbers, aided by the tool of scientific notation. Modern astrophysicists don’t walk around with a deeply developed intuition for the vast scale of the universe—it’s too much for the human brain. But these scientists do walk around with a grasp of the relevant numbers involved. As an example, here are some of the numbers I carry in my head to understand the universe’s size: • A lecture hall is approximately 10 meters across, and light travels across it in about 30 nanoseconds. We will be using light, which travels at 300,000,000 meters per second to quantify distances. • The earth is 6378 km in radius, and light would travel seven times around the earth in one second if it could travel in a circle like this. • The moon is about one-quarter the diameter of the earth, and is 1.25 light-seconds away—corresponding to about 30 earth diameters to scale earth−moon distance • The sun is 109 times the diameter of the earth, and about 8 light-minutes away (this is 1 “Astronomical Unit,” or A.U., and is about 150 million km). • Jupiter is about 40 light-minutes from the sun (5 A.U.). • Pluto is about 40 A.U. from the sun, or about 5.5 light-hours out. • The next star is 4.5 light-years away—take a moment to appreciate this big jump! • The center of the Milky Way (our galaxy) is about 25,000 light-years away. A galaxy is a gravitation-ally bound collection of stars: islands of stars—many of which make up the universe. • Large galaxies like our own are about 100,000 light-years across. • The nearest external large galaxy is the Andromeda galaxy—about 2 million light-years away (20 galaxy diameters). • The nearest large cluster of galaxies (Virgo Cluster) is about 50 million light-years away. • The edge of the visible universe is about 13.7 billion light years away. 1As you can see, the range of scales is too huge to be described all at once by a single measure. We went from small fractions of a light-second (light crosses the lecture hall in 0.00000003 seconds, and can cross the United States of America. in about 0.01 seconds) to huge quantities (billions!) of light-years. In total, going from the lecture hall to the size of the visible Universe takes us through 25 orders-of-magnitude (factors of ten). At best our puny brains are capable of comprehending maybe 8 orders-of-magnitude directly (1 mm grain of sand to 100 km scale visible from mountain-tops). Outside this direct experience, we rely on the numbers to convey the relative scales. What Do We Know About the Beginning? What we see when we look into the universe today is the illusion that all galaxies are hurtling away from our own, as if we were sitting at the center of some momentous explosion. The farther the galaxy, the faster its apparent recession from us. This effect is seen in the wavelengths (colors) of light from distant galaxies. Wavelengths from receeding galaxies are shifted toward the red (“redshifted”) by a precisely measureable amount—analogous to the Doppler shift we hear in the pitch of an ambulance racing past. The farther the galaxy, the greater the redshift, and thus the faster it is moving away. As an aside, this expansion rate is characterized by the Hubble Constant, 70 km/s/Mpc. These strange units mean for every megaparsec (Mpc, or 3.26 million light-years) we go away, galaxies are receding by another 70 kilometers per second. There are two illusory aspects to this astounding observation (first recognized in the 1920’s). The first is that though we appear to be at the center of the expansion, we are not. Every galaxy would make the same claim. Think about it this way. We look at galaxy A 10 Mpc away, receding at 700 km/s. Straight beyond galaxy A is galaxy B, 20 Mpc away, receding at 1400 km/s (Figure 1). Imagine standing on a planet around a star in galaxy A. In one direction, you can look back and see our galaxy, the Milky Way. On the opposite side of the sky you see galaxy B. Both are 10 Mpc away, and both appear to move away from you at 700km/s. So on galaxy A, it also appears that all galaxies recede from you. Two good analogies help illustrate this concept. For the first, imagine galaxies drawn on the surface of a balloon, and the balloon being blown up. As the “fabric” of the balloon stretches, galaxies move farther away. The farther, the faster. To each, it appears to be at the center of the expansion. But there is no center (here we confine our thoughts to the surface of the balloon—unaware of the three-dimensional center of the spherical balloon we can see).The second analogy is that of a baking raisin bread. Now imagine the raisins to be galaxies, and the bread is space itself. Again, each raisin sees all others moving away from it, and the farther the raisin, the faster it appears to move away. But there really is no center (forget that the bread has edges, or that it’s in your oven). The second correction to the statement that “we see galaxies receding with an ever-increasing velocity as we go farther” is subtle. But the correct picture is not that galaxies are whizzing out into a pre-existing, empty space. The right way to look at it is that space itself is being created/expanded between the galaxies. The galaxies are simply along for the ride, being carried in the expanding space. Here, the raisin bread analogy is particularly useful. The raisins (galaxies) are not zooming through the bread (space), but rather the bread (space) itself is expanding. This picture ultimately agrees better with observation, and is consistent with the predictions of general relativity. Space itself is being “created” as the universe expands. It doesn’t take a great leap of imagination to consider that if space is expanding in all directions, it used to be smaller. Galaxies used to be closer. How far do we carry this back? We can make the bold statement that maybe we should carry it to the extreme—to a time when the whole universe was smaller than a grain of sand. This seemingly preposterous extrapolation is, surprisingly, supported by observations. If the universe were once this small, it would also have been so very hot that even protons and neutrons would have been evaporated into quarks. If we play this game—knowing what we do about particle physics from our accelerator experiments—we can predict the relative abundance of the light elements that would have frozen out of this quark soup as the universe expanded and cooled. This simple (in concept) game actually gets the story right! It predicts the abundances of hydrogen, helium, lithium, etc. that we see in the primordial gas clouds that still surround us. Other predictions likewise work with this scenario (cosmic 2From Milky Way (MW) perspective From galaxy A perspective MW A B MW A B 0 700 1400 0 700 −700 Figure 1: The same motions of the Milky Way, and two galaxies labled A and B. The frame on the left shows both galaxies receeding from MW, B traveling faster than A. From the perspective of galaxy A, both B and MW move away at the same speed. microwave background radiation, ages of oldest stars). This model of the beginning of our universe is called the Big Bang model, and has gained nearly universal (forgive the pun!) acceptance among scientists. How Big is the Universe, Really? This simple question has a somewhat complicated answer that may involve new ways of thinking, but we’ll try to get to the bottom of the issue. To start, I note that the universe is largely made up of space. By space I mean vacuum—emptiness—nothing. Though we have galaxies of stars littering our skies, even these have lots of empty space in them. On the whole, if you smeared out all the atoms in the universe uniformly, you would end up with less than one hydrogen atom per cubic meter. That’s sparse! Even in our locally dense galaxy (most of the universe is space between the galaxies), stars are like grains of sand several miles apart! Since the universe is mostly empty space, it is appropriate to talk about the nature and extent of theuniverse in terms of the nature and extent of space itself. Here is where things start to get weird. We allpicture space as being three-dimensional and flat. By flat, we mean Euclidean. By Euclidean, we mean thatall the properties of geometry we learned about in high school apply. These are statements like: parallellines remain parallel forever; the angles in a triangle add to 180◦; space is infinite in extent. Such statements appear to be valid in our daily experience.This picture of flat space formed the backdrop of physics throughout the Newtonian era. Einstein changed this when he suggested two radical ideas: 1. Time must be included in our description of space into a unified concept of space time. Time and space mean different things for observers moving with respect to each other, becoming inextricably mixed.This is the subject of special relativity. 2. Space-time may be curved—there is no requirement for flatness. What’s more, the presence of mass curves spacetime. This is the subject of general relativity. Is nothing sacred? Apparently not. These concepts truly re-shaped the way physicists think about space. Not surprisingly, the description of the nature of the universe (the size and shape of space) is profoundly impacted by this paradigm. In addition to local spacetime curvature due to masses (stars, galaxies) within the universe, there may be a global curvature that apples to the whole of the universe. It is next-to-impossible to imagine in your head what it would mean for all of three-dimensional space (actually, 4-dimensional spacetime) to be curved. B A C Figure 2: Ant experiments on a sphere: A) the straightest line possible—a great circle—comes back on itself; B) Initially parallel tracks eventually converge; C) A straight line triangle on a sphere has angles that add to more than 180◦, in this case 270◦. Curved into what? But we have some lower-dimensional analogies to help us appreciate what this might look like. 3.1 A Two-dimensional Analog Imagine you are an ant living on a basketball. You can only move around on the surface, so that you essentially live in a two-dimensional space. Another way to say this is simply that the basketball surface (texture notwithstanding) is a two-dimensional surface existing in our three-dimensional space. This third dimension allows us to see what the ant cannot. If the ant makes a smelly deposit on the surface and runs away in horror, it will ultimately come back on the surprise, though never deviating from a straight line. We call this straight line a great circle (see Figure 2A), because to our three-dimensional eyes, we can see that the path of the ant through three-dimensional space is a circle (like an equator). To the ant, the line was straight as could be. No matter what direction the ant chose to run in, the result would be the same as long as the ant kept to a straight line. So this space is finite: it does not go on forever. The next experiment the ant attempts is to walk parallel to another ant. They both start out side-by-side on the basketball’s “equator,” and agree to walk “north.” Once they decide this, they start out walkingparallel in the north direction, but agree not to look at each other—just their compasses. Some time later, they bump into each other. Each suspects the other of deviating, while knowing that they themselves did not. In fact, neither deviated from a straight line (Figure 2B). But Euclid’s relationships don’t hold on this curved space. Parallel straight lines will always converge on a sphere. In this case, the convergence would be at the “north pole.” (Take a look at how the lines of longitude converge at the north pole of a globe, despite starting out parallel at the equator and each representing perfectly “straight” great-circle paths.) The last experiment the frustrated ant tries is to verify that the three angles inside a triangle add to 180◦. The ant starts at the north pole, walks in a straight line south to the equator, turns right (90◦) to follow the equator, walks a quarter of the way around the equator, then turns right again (90◦) to head back to the north pole. On reaching the north pole, the ant finds that the angle that its current path makes to the original path from the pole is 90◦, so that the three interior angles of this “straight-line” triangle add to 270◦—much bigger than the expected result (Figure 2C). The lesson is that the rules of Euclidean geometry don’t hold on curved spaces. The analogy to our universe is as follows. If our universe has so-called positive curvature, then any straight line ultimately comes back on itself, parallel lines ultimately converge, and angles within a triangle add to something greater than 180◦. Now it should be pointed out that had the ant on the basketball performed the triangle (or parallel line) experiment over a very small and confined region of the basketball, Euclidean geometry would have appeared to work to a high degree of precision. By analogy, the earth looks pretty flat over small distances. We know that the universe is very large—because we see new and different stuff in every direction for a long way. So in our tiny local region, things look pretty flat. But is the large-scale universe curved? This 4Figure 3: Possible geometries of the universe, in two-dimensional analog. has been an open question in cosmology, and we’re finally gaining some resolution. 3.2 Types of Curved Universes To motivate more concretely the notion that the universe is curved, I mentioned above that Einstein’s theory of general relativity produces spacetime curvature—in fact, it produces positive curvature—like that of a closed sphere. So the question of “how much curvature” boils down to “how much matter is there in the universe?” We know that the universe is expanding, based on galaxy redshifts. Since matter is gravitationally attracted to itself, the presence of matter in the universe may be sufficient to slow—even halt and reverse—this expansion. In other words, the presence of mass applies brakes to the expansion. But is there enough matter present to halt the expansion? Enough to reverse it? In a universe that contains only gravitating matter and empty space, the question of the fate of the universe and the type of curvature are intimately related. A universe with more than enough matter in it to halt the expansion has enough matter to make it positively curved on the whole. This type of universe would wrap back onto itself. Like the ant traveling in a straight line and coming back to the same spot, so we would come back to earth if we flew a straight line in a rocket for a very, very long time. Other properties of positive curvature would also be present: parallel lines would eventually converge, and triangle angles would add to greater than 180◦ (the larger the triangle, the greater the deviation—like on the surface of the basketball). Besides these geometrical properties, this “closed” universe would ultimately turn back on itself and experience a Big Crunch when it all came back together. Figure 3 shows the possible geometries, with the closed geometry on top. On the other extreme, if the amount of matter in the universe is insufficient to halt the expansion, the resulting geometry has a net negative curvature. This is harder to visualize, but the properties are that it goes on indefinitely (you would not wrap back on yourself if traveling in this space), parallel lines now diverge, and triangle angles add to less than 180◦. The best visualization I can offer here is that of a Pringle’s potato chip: saddle-shaped. This kind of surface has all the right geometrical properties, if for instance an ant were to do similar experiments to what it did on the sphere. The only catch is that you have to imagine a Pringle of infinite extent (yum). The negatively curved universe is said to be “open,” as it is infinite in extent, and will never re-collapse. It will continue to expand forever. The existence of matter may slow down (decelerate) this expansion, but it will never be enough to stop it. Precariously balanced between these two extremes is a flat universe. A flat universe has just the right amount of matter to exactly balance the expansion, so that ultimately the universe’s expansion will exactly stop (as time marches toward infinity). In this case, there is no net curvature, and Euclidean geometry holds across the infinite extent of the universe. Though seemingly impossibly tuned to have just the right amount 5of matter (not a teaspoon more or less), this has been a favorite of theoretical cosmologists because they think this condition would have been automatically satisfied the way the universe started. If the universe is close to being flat, but not precisely so, then it has some net curvature, but this curvature may be hardly noticeable. This is analogous to saying that the effects of earth’s curved surface are not very noticeable over small scales (like on a soccer field), while the soccer ball is very noticeably curved. In otherwords, a universe that is positively curved, but very large, will appear pretty flat on the small part we can see. It is very difficult to unambiguously tell the difference between these scenarios through our observations of the universe—though we have been surprisingly successful at setting limits on this curvature using the CMB. Geometry Summarized If the universe is composed only of gravitating matter and the empty space in between, then the geometry of space—positive curvature, flat, or negative curvature—is intimately connected with the amount of matter in the universe. This is also then connected with its fate. A nice verbal relationship exists to sum this up: a positive-curvature universe is said to be closed (finite) and is both finite in spatial extent (wraps back onto itself) and in the time domain (will ultimately re-collapse). A negatively curved universe is said to be open, and extends infinitely in both time and space. The flat case is a special, limiting case of the open scenario—it too is infinite in extent and will go on forever in time, but only just so. The Universe As We See It In an effort to determine the matter density of the universe, and thus its ultimate fate and geometry, as-tronomers for many years pursued a measurement of the deceleration of the matter in the universe. The logic was that if any matter existed at all (and clearly it does), the net gravitational effect between all bodies in the universe would apply the brakes to the expansion, slowing down its rate. The effect is relatively small, and it took a very long time to be able to make any measurement. Finally, in the late 1990’s, two independent teams of physicists and astronomers had managed to make a measurement using the light from a special type of supernova (exploding star) thought to act as a “standard candle”—having the same intrinsic brightness no matter when and where in the universe it happened. The result they found was startling. The data thatstared them in the face proclaimed that the universe is actually accelerating presently! It’s as if the balloon is being blown up more rapidly today than yesterday. Nobody (well, practically nobody) had anticipated this possibility. But this provides an example of the triumph of measurement over theory. You can’t argue with measurement. (Well, you can, actually, and should. You should make sure the measurement is valid and that you aren’t being fooled by other effects that you have not yet considered. And believe me, this surprising data has been challenged extensively.) In a moment of severe whiplash in the astro physical community, we suddenly had a huge mystery on our hands. If the universe is accelerating, what’s pushing it apart? Why isn’t gravity working like we thought it should? These sorts of challenges crop up in science from time-to-time, forcing its practitioners to take a hard look at their fundamental assumptions. This is a very healthy process, and it gives me great hope in humanity that we, as humans, do not cling maniacally to a dearly held belief when new evidence points to the contrary. Lest you think that these revolutions “undo” any of the previous measurements and experience from the past, let me assure you that the entire body of measurement and observation stands. The revolution is on the side of theory, whose job it is to explain the collection of empirical data in a self-consistent way. These revolutions typically make it clear that we simply didn’t have the full theoretical picture, or that we can’t get away with an over-simplified view. Around the same time as the discovery of the universe’s acceleration, astrophysicists looking at the afterglow of the Big Bang (called the cosmic microwave background: CMB, or also the surface of last scattering) were intent on measuring the shape of our space. They could do this because they could predict in great detail what kinds of structures existed at this stage in the universe’s development, when it was 6only 380,000 years old. By structures I just mean temperature variations (departures from uniformity)—or “structure” in the density/temperature of the early plasma. They knew, in effect, how large the largest structures could have become in that time—in real units like meters! Given this, and also armed with the knowledge of how far the surface of last scattering is, the apparent angular size of these blobs on the sky then tells us what kind of geometry we live in. Are we drawing this long, skinny triangle on a positively-curved space, like a basketball, on a negative potato-chip, or in plain Euclidean flat space. The answer—much to the delight of many theorists—came out to be that space is flat. If we quantify this in terms of the amount of matter required to make for a flat universe, the answer came out to indicate the critical density within 2%. In other words, if the universe had too much stuff, it would have positive curvature. Too little stuff and it would have negative curvature. We appear to be in the “just right” scenario, to pretty high precision. A third leg of evidence supported both by measuring masses of huge clusters of galaxies, and also from secondary “structure” in the CMB indicates that the universe only has 30% of the gravitating matter necessary to flatten the universe. How could this be consistent with the previous CMB finding that we were within 2% of the magic value? The answer is in the subtle use of the word “gravitating” above. It turns out that 70% of the total mass-energy (i.e., stuff) in the universe is of a non-gravitating form. We call this “dark energy” because we can’t see it, it’s not matter, and we frankly have no idea what the stuff is. But it’s the stuff that is responsible for the acceleration of the universe—it’s pushing us apart. Thanks to astrophysical measurements, we now know exactly how much dark energy, dark matter, and ordinary matter exist in the universe. But we still don’t know what any of the “dark” stuff actually is. Ideas abound, but no one pays close attention to ideas unless they suggest additional tests or measurements that can support or refute them. What Does It All Mean? This is mind-blowing stuff, to be sure. We’re talking about the geometry of space, and suddenly we find out that it is indeed flat, but that there are constituents in the universe that we know very little about. It’s confusing, and may sound even absurd (more like fantasy or science fiction than science). But scientists are serious about this. It’s hard to drag along a skeptical bunch like scientists on a wild ride like this without an awful lot of experimental evidence. Many scientists are still uncomfortable with this surprising new landscape. But almost all acknowledge that we’re faced with striking measurements that will likely radically change our fundamental understanding of what makes up the universe. To talk concretely about the meaning of these observations, let me answer some common questions that always come up in mind: Is the universe infinite in extent? If the geometry of the universe is indeed flat, as we measure it to be, then yes: the universe goes on forever. This doesn’t mean that we can see the whole universe, though. We can only see about 13.7 billion light years away in any direction. So the universe is finite if we can only see so far, right? These are unrelated things. Because light travels at a finite speed (albeit fast), when we look far away, we look back in time. When we look 13.7 billion light years away, we see the universe as it existed near the time of its birth. There are no stars or galaxies there yet. A being sitting at that point in the present day would find themselves in a setting that looks much like the one around earth today. If they looked back toward earth, they would see our local environment as it was 13.7 billion years ago—long before the sun or even our galaxy formed. We would be the limit of their vision: the edge of their visible universe; their CMB. You could play this game forever: at each horizon edge, the universe looks normal, and there is a new horizon in all directions. Imagine the universe as a huge ocean. In the ocean, you can only see so far due to the cloudy water (maybe several tens of meters). It doesn’t mean that stuff doesn’t exist outside of the visible horizon. If we can look 13.7 billion light years away, shouldn’t we see the Big Bang? Yes! And in fact, we do! Only light isn’t free to travel through empty space until all the electrons are moved out of the way. So as the hot plasma emerging from the Big Bang cooled, ultimately things settled out enough so that electrons could pair up with Hydrogen and Helium nuclei, so that the plasma became neutral. Now light could stream freely across the universe. This is what we see in the CMB: it is the plasma afterglow of the Big Bang, seen about 380,000 years after the universe started—just cool enough to have become neutral. We see it in every direction 13.7 billion light years away as an almost perfectly uniform microwave glow. Truly its amazing, really. If we know the universe is flat to 2% precision, is there room for error? Absolutely. All we are prepared to say for now is that over 13.7 billion light year scales, the universe looks pretty flat: it doesn’t deviate by more than 2% from being flat. But, the possibility exists that the universe is still curved on much larger scales. It’s just like the fact that the earth looks flat locally, over small scales, but is curved on the whole. The universe could be closed into a sphere, but on a much larger scale than what we can see. A 2% limit translates to a factor of 50 (it takes 50 2%’s to make 100%), so we could say that if the universe is finite, it must be at least 50 times bigger than our 13.7 billion light year horizon. Now Finally! What is the ultimate fate of the universe? Ten years ago, the answer would have simply been that it depends on how much matter is in the universe. If the universe had critical density, it would expand forever, but eventually come to a stop infinitely far out into the future. But it was already looking like there was too little matter to do this, so the universe would expand forever. Now things are more complicated. Even though we think the universe is flat, it has too little gravitating matter to halt the expansion, and moreover, seems to have a dark energy that is accelerating this expansion. Under this scenario, the universe will in essence blow itself apart. But it takes a long time (tens of billions of years), so don’t pack your bags yet. Things seem uncertain now . Is the fate of the universe also uncertain? For sure it is. Until we understand what this dark energy is, we won’t be able to predict with any certainty how it will evolve as the universe ages. If things don’t change, the above scenario will hold. It’s our best guess in the absence of a complete understanding. But as a consequence of the recent series of fantastic measurements, we can say more now than ever before about what we think will happen. What does this mean for humanity? Why should I care? Great!? You may not care. You may not find this to be relevant to your life. That’s one of the great things about our lives: we get to choose what we are interested in, and pursue it. But in general, humans have always been curious about origins. Though not every human will be interested in dinosaurs, as a whole we are certainly intrigued, and have learned much from studying them. Science is the process of looking to our surroundings to see what we can learn about how we got here. Recent astrophysical observations are painting a rich story that we simply can’t ignore. Nor do we want to. How it will affect humanity in the very long term is an open question. Does it change the way you live your life or treat others if you know that the universe is a transient thing?—that it will one day expand itself to oblivion? Does it change the frequency of religious wars on this planet if in 500 years we all share a common creation story? At this point, this is more complicated than predicting the fate of the universe. Humans are frighteningly complex! Life in the Universe I am no expert on life in the universe. There is a new and growing field of science called astrobiology that delves into the requirements for life, and explores the extremities in which life on the earth has been able to thrive. This direction of exploration may then define for us how likely it is that life—however simple—could exist on other planets, in comets, etc. But we can at least explore an aspect of the question of additional life in the universe based on what we know about the universe. Does life exist elsewhere in the universe? Let’s play the numbers game. Our galaxy is composed of roughly 100 billion stars. How many of these stars have planets? We’re finding that quite a few do! We already know of over 100 stars aside from our sun that have at least one planet. the numbers are: 146 planetary systems; 170 planets; 18 multiple-planet systems (as many as 4 in some systems). At present, we can only detect large Jupiter-like planets in orbits that are relatively close to their stars: these produce the strongest tugs on the parent stars, which is what we measure. But it appears that a substantial fraction of stars—at least 5%—have planets. As our detection techniques improve, we may find many smaller planets and find that indeed most stars have planets. Right now, we would not be able to detect our own set of planets around another star using current techniques. Yet we know we are here. This means solar systems much like our own are still beyond our detection limits. Putting the number of stars in our galaxy together with an estimate that 10% of stars have earth-sized planets (just a guess), we get that 10 billion stars in our galaxy alone harbor earth-like planets. By earth-like, I just mean rocky planets with masses comparable to earth’s mass. Not all of these earth-like planets will be in the “habitable zone” where we see life in our solar system. Example: Venus is too hot, Mars is too cold, though both are “earth-like” by the definition above. Let’s say only 1% of these earth-like planets happen to be in the “Goldilocks” just-right zone. Now we have as many as 100 million habitable planets in our galaxy. We don’t know yet how rare life is. With only one planet to guide us, the estimates cover a huge range. But let’s say for the sake of argument that the chances for life to form are a remote one-in-a-million given a habitable planet. Some would argue that it’s closer to near certainty that life (we’re talking single-cell organisms here) forms. But with the pessimistic long-shot odds of one in a million, that still gives 100 instances in our galaxy. Now hold onto your seats. There are approximately 100 billion galaxies within our 13.7-billion-light-year horizon. So now we have 10 trillion instances of life in our universe given the harsh one-in-a-million odds. Hard to imagine this not panning out. But wait, there’s more. Our visible universe is but a small portion of the entire universe, We know the universe is at least 50 times the size of the visible universe within our horizon.But this is in linear size—radius, or diameter. In volume, the universe is then at least 503 = 125, 000 times larger in volume than our visible volume. Assuming physics looks the same outside our horizon, there are now about a quintillion, or 1018 instances of life in the entire universe, as a lower limit! Our estimates could be off here and there; they are very rough. But it is hard to reduce a number this big to zero (or one, since we’re here, at least) by revising estimates of probabilities. The sheer size of our universe and the resulting number of stars and planets is so absolutely staggering so as to overcome the long odds for developing life. One other aspect we haven’t reflected on is the enormity of time over which life has to develop. We can’t really easily grasp time periods longer than maybe 1,000 years. Yet it takes 1,000 of these periods to constitute one million years, which is still short on geological timescales. It would take 1,000 of these one-million-year periods to make one billion years. The universe is 13.7 billion years old, and we find fossil evidence of simple life on the 4.5-billion-year-old earth as far back as about 3.5 billion years. Interestingly, the earth was not very hospitable when it was young. It may have taken only (only!!) a few hundred million years for life to form once the earth was a calm and hospitable neighborhood. Even this geologically short period is sooooo long that it is truly impossible for our brains to take it in—much like how we started in comprehending the vast size of the universe. Intelligent life is another beast altogether. It’s a long road from simple organisms to pigs and things. But nature provides a self-ratcheting mechanism to constantly push the developmental arms race toward greater 9complexity. I’m talking here about natural selection. But by now I have strayed far from physics, and should leave this topic for your continued ponderings. DARK MATTER By Rohit Sharma INTRODUCTION The search for the origin of the universe has taken us deeper and deeper into the heart of the micro element world. Gazing into the heavens makes it hard to believe, that the universe we perceive as so unbelievably clear and transparent, is in reality very dense. That is to say the distance between particles in space are equal distance of particles in matter of what we perceive as a solid on Earth. Modern theories accept that our universe is comprised of macro and micro mass. Many scientists assume that all this matter came from a BIG BANG, Logic may posit the birth of the universe not a vast array of thermal grandeur but rather a meager whimper a sequence of consequence. Many scientists now believe the universe is a closed system and that DARK MATTER is filling this universe. In astrophysics, dark matter refers to undetectable matter or particles whose presence explains unexpected gravitational effects on galaxies and stars. Various assumptions were made on the composition of dark matter: Molecular gas, Dead stars, Brown dwarf stars, Black holes, etc However, the observations (or rather lack of direct observations) would imply a non-baryonic nature (proton, neutro), and thus still unknown nature. According to galaxies formation and evolution models as well as cosmological models, dark matter would represent approximately 30% of the total mass of the Universe. Starting from the number of stars’ and galaxies’ revolutions (on the cluster level), it is possible to measure the mass of the dark matter, and to deduce its distribution. A great quantity of this matter should be within the galaxies, not in the galactic disc but in the form of a halo including the galaxy. Indeed, this configuration allows a stability of the galactic disc. Moreover, certain galaxies have rings perpendicular to the disc and composed of gas, dust and stars. There, the halo of matter would explain the formation and stability required. On the other hand, it is impossible that the dark matter be in the galactic disc, due to the fact that we should then observe an oscillation perpendicular to the disc in the stars movement (which is not the case). The study of satellite galaxies (small galaxies turning around other galaxies) obliges to think of very wide halos: approximately 200 or 300 kpc. By comparison, the Sun is located at approximately 8, 6 kpc center of our galaxy. The galaxy of Andromeda – galaxy nearest to us – is located at 725 kpc, that is to say a little more of the double of the halo radius of our galaxy. These halos could be common between close galaxies. Dark matter composition research – Ordinary matter Scientists turned initially to ordinary matter (baryon) for their research and reviewed all the types of particles which could contribute to this gravitational field, such as gas clouds, dead stars or black holes. What are Gas clouds? In the 1990’s, precise cartographies of the universe x-rays emission sources – gathered thanks to the Rose Satellite – highlighted the presence of gigantic ionized gas clouds within galaxy clusters; clouds of several million degrees non-emitting in the visible field. Moreover, these clouds seemed to contain ten times more matter (at least, luminous matter) than the galaxies of these clusters. Was this finally the missing matter? Unfortunately not. On the contrary, these clouds are the proof of the presence of dark matter around the galaxies. Indeed, to reach such temperatures, the particles constituting the cloud must be accelerated at very high speeds (approximately 300 km/s), and this acceleration comes from the force of gravitation. However the quantity of gas is insufficient to generate such a gravity field. Similarly, the stars alone cannot prevent the gas cloud from escaping. The gravitational influence of the dark matter is then necessary to explain the containment of these clouds near the galaxies. Moreover, the shapes of these clouds are helping the astronomers and astrophysicist in their research to determine the dark matter’s distribution in the neighbourhood. Black Holes? Much more massive than MACHO or stars, black holes could have been good candidates. Some of them reach a mass of 10.000 solar masses (in particular super massifs black holes, in galaxy’s centers). However, it would be necessary to have nearly a million of such black holes in a galaxy to fill the lack of matter; a too large number knowing the effect of black holes on neighboring stars. Indeed, black holes sometime cross the galactic disc and disturb the movement of stars. With such a number of black holes, the movements of these stars would be strongly amplified, which would make the galactic disk thicker than what is currently observed. Remain the stellar black holes (a few solar masses), not easily detectable, and the black holes of a few tens or hundreds of solar masses, whose nature of formation has not been explained yet. In all cases, the track of black holes as being the famous dark matter was abandoned, and the astronomers are leaning on the no baryonic matter type. Dark matter composition research – No baryon matter The Big-bang model makes it possible to calculate the number of baryons in the Universe, i.e. the number of helium 4 and hydrogen atoms, formed at the time of the primary nucleosynthesis. The astronomers calculated that baryon matter amount for approximately 4% of the critical density. However, to explain the flat geometry of the Universe, the Universe’s total matter must be of 30% of the critical density (the remaining 70% being dark energy). 26% of the critical density is then missing. Those 26% would be constituted of other particles those baryons. First observational evidence of dark matter In 1933, Swiss astronomer Fritz Zwicky of Caltech decided to study a small group of seven galaxies in the Coma Cluster. Its objective was to calculate the total mass of this cluster by studying the speed (or rather the dispersion speeds) of these seven galaxies. By using Newton laws, he calculated its mass ‘dynamic mass’, then compared it with the ‘luminous mass’, which is the mass calculated from the quantity of light emitted by the cluster (by making to the assumption of a reasonable distribution of the star population in the galaxies). The dispersion speeds (or in other words, how the speed of these 7 galaxies differed from each other) is directly related to the cluster’s mass. In fact, a star cluster can be compared with a gas, where the particles would be galaxies. If the gas is hot and light, the dispersion speed of the particles is high. In the extreme case, the particles which have a sufficient speed leave the gas (evaporation). If the gas is cold and heavy, the dispersion speed is weak. Zwicky was surprised to note that the speeds observed in the Coma Cluster were very high. The dynamic mass was 400 times larger than the luminous mass! At the time, the methods and the precision of measurements were not accurate enough to be neglected. Moreover, massive objects such as brown dwarf, white dwarf, neutron stars , black holes and in general of poorly non radiating objects were little known. And same for interstellar dust and molecular gas. Zwicky announced its observation to its fellows, but they were not interested. Zwicky’s reputation was not so good due to a strong character and its measurements were criticized due to measurement uncertainties. The same phenomenon was again observed in 1936 by Sinclair Smith during the calculation of the Virgo Cluster’s total dynamic mass. This one was 200 times more important than Edwin Hubble’s estimate. According to Smith, is could be explained by the presence of matter between the galaxies of the cluster. Moreover, the galaxy clusters were still considered by a great number of astronomers as of temporary structures rather than of stable structures. This explanation was enough to justify excessive speeds. At the time, astronomers had other ‘more imporant’questions to solve (such as the expansion of the Universe) and the question of this difference between the dynamic and luminous mass was let aside for several decades. Dark matter between galaxies? The movements of galaxies within the clusters showed similar problems than with the rotation of stars in galaxies. This suggests the presence of dark matter between the galaxies; although nothing proves yet that these two problems are related. On a galaxy scale, the dark matter rate would be up to 10 times that of the luminous matter, but on the clusters’ level, it would be much more important: up to 30 times the “visible” mass of these clusters. In 1996, astrophysicist Yannick Mellier and his team decided to measure the quantity of dark matter in all the Universe and to draw up a chart of its distribution between the galaxy clusters. The method used was to make a large scale statistical study of the galaxy deformation due to gravitational interaction of dark matter existing between the Earth and these clusters. This gravitational intercation is visible as it deviates the luminous rays sent by the galaxies (their image arrives deformed). A statistical study on a very large scale (the area of the sky studied was the apparent size of the moon and on a depth of 5 billion light-years) made it possible to neglect the local deformations due to other galaxy clusters. This study led in March 2000 to the a cartography. The dark matter takes the shape of long intersecting filaments. The quantity of matter of the universe should represent one third of that needed to reach the critical density, the remainder made up of dark energy. A new similar study is in hand, always by the team of Yannick Mellier, with this time a larger CCD camera, allowing the study of 20 times the previous field of view. Dark matter composition research – The neutrino The neutrino is a particle introduced for the first time in 1930 by Wolfgang Pauli, before the discovery of the neutron (one year later), and which was detected in 1956 by Frederick Reines and Clyde Cowan. This particle – insensitive to electromagnetic forces and strong nuclear force – is emitted during a beta desintregration, along with an electron. The neutrino doesn’t interacts much with other particles, which makes it a good candidate for dark matter. The mass of the neutrino was considered very small, even null. With the problem of the missing mass of the Universe, the physicists wondered if the neutrino would have a nonzero mass. Especially as the neutrino is the most abundant particle in the universe, after the photon. However, the experiments Super-Kamiokande and SNO (Sudbury Observatory Neutrino) revealed a too small mass to consider that this particle would constitute the dark matter. The neutrinos could represent, at best, 18% of the niverse’s total mass. Dark matter composition research – WIMP The WIMP (Weakly interactive massive particles) form a class of heavy particles, interacting slightly with matter, and constitute excellent candidates with the nonbaryonic dark matter. The neutralino postulated by the supersymetric extensions of the standard model of particle physics. The idea of supersymmetry is to associate each boson to a fermion and vice versa. Each particle is then given a super-partner, having identical properties (mass, load), but with a spin which differes by 1/2. Thus, the number of particles is doubled. For example, the photon is accompanied by a photino, the graviton by a gravitino, the electron of a selectron, etc. Following the impossibility to detect a 511 keV boson (the electron partner), the physicists had to re-examine the idea of an exact symmetry. Symmetry is ‘broken’ and superpartners have a very important mass. One of these superparticules called LSP (Lightest Supersymmetric Particle) is the lightest of all. In most of the supersymmetric theories (without violation of the R-parity) the LSP is a stable particle because it cannot disintegrate in a lighter element. It is of neutral color and electric charge and is then only sensitive to weak interaction (weak nuclear force). It is then an excellent candidate for the not-baryonic dark matter. First observational evidence of dark matter It is only 40 years later, in 1970, that the question of the existence of this dark matter reappeared. Starting from the analysis of the spectra of galaxies, the American astronomer Vera Rubin studied the rotation of spiral galaxies. The problem was the same as the comparison between the dynamic and the luminous mass of the galaxy clusters. It was a question of knowing if “luminous mass”, i.e. the mass which is calculated from the presence of stars, is relatively equal (except for some corrections) to the dynamic mass. It should be noted that the dynamic mass is normally the only true mass, as it is a measurement of the mass deduced from its gravitational influence. Any mass being subjected to gravitation, there is no reason to think that the dynamic mass observed is false. It is not as simple for the luminous mass. To measure the latter, the assumption is made that all the mass of the galaxy (or the galaxy cluster) is made of stars. These stars radiate, and if one knows (but it is very difficult) their distribution (mass, number, age, etc), the visible light is then a good way to determine the mass. By analyzing the spiral galaxies’ spectrum such as the Andromeda Galaxy (which section is visible), it is possible to calculate the curve from its rotation. The curve of rotation describes the number of revolutions of the galaxy according to the distance to the center. This curve of rotation is a direct measurement of the total distribution of matter in the galaxy. The maximum speed of rotation of a spiral galaxy is located at a distance of a few kiloparsecs from the center. It is then supposed to decrease, following a Keplerian decrease. Indeed, the stars at the periphery of the galaxy are in orbit around the center (in the same way as planets orbit around the Sun). The stars in periphery of the galaxy thus turn less quickly than those closer to the center. The curve of rotation, after a maximum, starts to go decrease again. However, Vera Rubin observed that the stars located at the periphery of the Andromeda Galaxy – as for other spiral galaxies – appeared to rotate too fast (speed remained almost constant when the distance to the center increased). The curve of rotation of spiral galaxies (some of them) was flat. Speed did not decrease whereas one moved away from the center. Many other similar observations were carried out in the 1980s, reinforcing those of Vera Rubin. These observations raised deep questions, because the curve of rotation is a good measure of the dynamic mass. No assumption about the age or the stars’ mass distribution is necessary A possible explanation was to think of the existence of a huge nonvisible matter halo surrounding the galaxies; a halo which would represent up to 90% of the galaxy’s total mass. Thus all the stars are almost in the center of the true extension of the “galaxy” (this time made up of the visible galaxy and the matter halo), and thus rotate normally. In other words, the stars located at the visible periphery of the galaxy, are not “far enough” from the center to decrease the curve of rotation. It still remains to directly observe this famous matter to confirm that it is the right explanation. The presence of dark matter is one of the possible explanations. It has the immense advantage of being simple and of going in the good direction. Indeed, the astronomers suspected that galaxies contain non-luminous stars (such as dwarf brown, dwarf white, black holes, neutron stars) which could represent a large part of the total mass of the galaxy, but which is not visible with optical instruments. The observation of spiral galaxies in other wavelengths (in order to better characterize the presence of not very luminous objects in the visible field) was one of the major efforts of astronomy to research and understand the problem. Dark matter composition Hot black matter and cold black matter Two main theories clash when they try to describe the nature of this dark matter: hot dark matter and cold dark matter. Those theories rely on the mass and speed of the particles composing the dark matter. In the case of the dark matter known as “hot”, the particles have speeds close to light, while the particles of black matter known as “cold” would be more massive and thus slower. The speed of these particles is crucial to the Big Bang model of cosmology and the order of formation of the Universe’s great structures. If the Universe cmopostiion is primarly made of hot dark matter, the very high speed of the particles would initially prevent the formation of a structure smaller than the supercluster of galaxies dividing up in galaxy cluster then in galaxies, then in smaller structures. It is the scenario known as “up bottom”, since the largest structures are formed initially, for then dividing. The best candidate to constitute the hot dark matter is the neutrino. On the other hand, if the cold dark matter is the main component of the Universe, the particles will go on a smaller distance and thus will erase the density’s fluctuations on extents smaller than in the case of hot dark matter. The ordinary matter would then gather to form galaxies (starting from gas clouds and smaller structures), which themselves will gather in cluster, then supercluster. It is the scenario known as ” bottom up”. The candidates for cold dark matter are WIMP and MACHO. These two theories were defended by Yakov Borisovitch Zeldovitch for the hot dark matter, and James Peebles for the cold dark matter. Currently, it is the cold dark matter model which seems to be the more consistent. Indeed, the galaxies are in a dynamic balance, which shows that they were created before the clusters (all do not seem stable yet). However, the current theory introduces a little bit of hot dark matter as it is necessary to explain the formation of galaxy clusters. Dark matter composition research – A useless assumption? More and more astronomers and astrophysicists think that dark matter does not exist. Rather than to search an explanation of the anomalies by an unobservable unobserved matter, it would more judicious to re-examine the physical laws constituting the standard model, and which are also questioned by even more fundamental problems. It would then be possible to solve several problems at The string theory and axions Some astrophysicists turn for example to the of the string theory. The string theory adds six new dimensions to the four usual ones (three dimensions of space and one dimension for time) and would place the dark matter in these new dimensions which are inaccessible for us; explaining why it would not be detectable. The electromagnetic and nuclear forces (strong and weak) would be confined in our four dimensions and could not leave them. On the other hand, the gravitation could disperse in other dimensions, and then drop in intensity compared to the other forces. Another theoretical particle, the axion, which would be extra-light (1 µeV), stable and which wouldn’t interact much with matter – a then practically undetectable particle – would make another good candidate for dark matter. This particle would solve problems arising from the antimatter (why matter won over antimatter). Various programs were launched since 1996 to try to detect axions. Star-gazing isn’t all about horoscopes and other fortune hullabaloo. Beyond trying to predict the future and guessing whether you’ll be lucky for tomorrow’s round of poker games with friends, astronomy is a deep study on cosmic bodies and phenomenon. Take dark matter for instance. Fundamental Particles If I may call them weakly interactive minuscule particles. The innermost secrets of matter are hidden in the world of quantum elements, these units form fundamental particles (fmp)\ Much of what is visible and non-visible in space is becoming more comprehensible. Men and women have managed great strides forming understandings, regarding celestial formations. Theoretically we have extracted two major non-visual particles, while not being subject to their physical existence to the extent of certainty, and by rationality present a philosophical foundation for science and evolutionary trends, as proof by logic and by reasoned pursuit of the senses. Their presence is inferred indirectly by the motion and effect on celestial objects, e.g. stars, galaxies and cluster galaxies. These fm particles compose all matter and the laws of physics they obey also apply to the local universe all inclusive. When measuring velocities in a region, sufficient mass must be present to restrain these objects from avulse conduct. Tracking their footprints we will uncover two minuscular matter structures as dark matter, representing about 45% + of the total mass in our local universe, the remaining 55% as potential rest energy (quantum thermal units*) These fundamental particles invisible to our technology shoulder the creation and stability of the local universe. This is the “dark matter”, I will refer to as fundamental particles. To presuppose that fundamental particles are a natural conception of our every day observations of matter, is in mans’ nature. The concept that there exist, interactive particles as the building blocks of all matter, stable and obey the laws of physics, and suggest that these particles will exhibit numerous functions, possess mass and be related to the general matter structure, does follow logic. Define fundamental particle as dark matter. The fundamental particles (fmp) are the fundamental building blocks of matter in a local universe these particles are a structure of more than one quantum thermal unit* this term describes particles with a structure which can not be broken down to form other particles. By definition a fmp can decay with a gradual reduction in the quantity of heat. Note: In scientific terms the smallest constituents or basic building blocks of all particles are pre or quantum particles (heat units) they pervade all space inclusive. To suggest a few fundamental particle Functions? 1—- fundamental particles (fmp), will not break down and succumb to the overwhelming weight pressures of a black hole’s critical mass. Fundamental particles consist of three flavors, negative, positive and neutral. Dark matter and PRE* represent 95 to 99% as the non-integrated mass (heat) and the remaining 1 to 5% as baryon matter or specific heat units (specific heat units are a coalescence of positive, negative and neutral fmps). 2 —Fmp negative form a 3 dimensional geometrical lattice, isometric, homogeneous, permeate and immerse all matter and assist to define the magnitude of a local universe with their volume inflation, The 90% + non-conjugated negatively charged fmp can not bind, have no partner, have no motion, isometric, homogeneous and rest as close as determined by their negative charge or flavor. 3—-the neutral particle is instrumental in the construction of plasma and must rest in an adjacent formation. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume and implement a route for thermal transference in the local universe. 4—Dark matter defines the perimeter of the local universe by its volume inflation. 5—Fmp assist in the formation of black holes, exerting pressure by means of the 3 dimensional geometrical lattice with all immersed contents therein. 6—Black hole fragmentation and a monumental fmp envelopment of each critical mass fragment, prolongs super inflation, allowing the fragments deeper penetration into space. This super inflation subserve seeding numerous sub-sectors of both the local and greater universe. 7—Fmp- and fmpn must be harmonious with all the macro mass in the local universe. Soon after black hole fragmentation and super inflation positive fundamental particles coalesce with one or both of the fmp- and fmp neutral. The remaining fmp- and fmpn without any possibilities of pairing, acquire an non assertive mode. 8—Fmp must be stable and long lasting, life as we know depends on their stability. 9—They are a rest mass (very little motion), able to transfer thermal information. 10—Dark matter permeates the air we breathe, the water we drink, us, earth, sun, galaxies and the local universe all inclusive. Black holes construct conditions that integrate all matter and form a region of space that has concentrated mass. Under extreme weight and external dark matter pressure black holes accrete fmp (dark matter) and alters their shape. At this pressure all molecules are reduced to their fundamental flavored state, as positive, negative and neutral particles. This critical mass condition compels the expulsion of all (+ -) potential rest energy units (quantum heat units) from the mass. How do fmp- function? The remaining fundamental negative particles are now non-conjugal and quiescent in this isometric lattice. In possession of near zero thermal value, no spin and no motion we may call them matter at rest. These fmp- form a 3 dimensional geometrical lattice, each particle occupying a point in the local universe. Synoptically set up this FMP- in a geometric formation from which they can not diverge and now are an interlocked force that can not be altered and are emersed in a neutral plasma. Let us use our solar system to demonstrate;- Let us posit, that the lattice and plasma are elliptical, isometric, and homogeneous, permeate and immerse all matter. Now imagine a rotating solar system afloat in a plasma sea and immersed in this sphere of dark matter are the sun, planets and all lesser matter. What we have established is a direct link between all macro matter, in a contactual sea of fundamental particles and in unison with the pre plasma binds every object in the solar system. Conceivable possibilities. All orbiting mass is permeated and immersed in dark matter and pre plasma fields. I believe the planets permeated and emersed in these plasmas are static buoyant bodies that float in elliptical whirl pool matrixes. All spinning macro matter, influence the fields to adopt a whirl-like motion, unlike a whirlpool it does not initiate a central coalescence effect to the whirling or orbiting matter. Now let us broaden our lattice to include all the matter within this entire universal sector to the periphery. What we have established is a direct influence with every object in the local universe a sector of the greater universe. The lattice and the plasmas (fmp and pre) bind all objects and rotate the sector as a unit. The hypothesis of natural conceptions are that celestial and galactic structures, exhibit numerous functions related to general matter structure of everyday observations. The concept that the solar system and galaxies rotate and they obey the laws of physics, it does follow logic, to assume that the local universe rotates likewise. Conceptions and natural observations have developed a hypothesis that these minuscule matter structures inferred as”dark matter”, is a predominate substance in the universe. The effects and presence are inferred indirectly through the motions of celestial objects. Dark matter is comprised of three particles, a positive, negative and neutral and these fundamental particles represent about 45 % of all the matter in the local universe. Baryon matter comprises about 1 to 5% of the total matter in the greater universe. The remaining 95 to 99% is referred to as dark matter and potential rest energy (PRE).\ Fmp- and fmp+ comprise about 30 to 40% of the dark matter. These are divided again about 95% fmp- and the remaining 5% are fmp+.\ Neutral particles comprise about 60 to 70% of the dark matter. These percentages may change some what, as they are hypothetical. Why this disparity? With so few positively charged fundamental particles this provides effortless propagation and reinforces the theory of the visual amount of baryon matter we are able to observe. The remaining non-conjugated negatively charged fmp cannot bind, have no motion and rest as close as determined by their negative charge or flavor. Their objective now is to form a 3 dimensional geometrical lattice, isometric, homogeneous, permeate and immerse all matter, in conjunction with neutral plasma and pre, define the magnitude of the local universe with their volume inflation. How is a lattice constructed? The initial “black hole eruption” scatters large fragments randomly every which way. This process of fragmentation is repeated many times each successive explosion results in smaller fragments (each containing millions of galaxies) hurled at random into a PRE filled greater universe. A monumental fmp envelopment of each critical mass fragment prolongs the initiation of super inflation and allow these fragments deeper penetration into the G.U. While fragments are hurling through G.U. they disperse a misty trail of dark matter and sub serve seeding numerous sectors forming a local universe. Immediately upon “critical mass breach” fmp begin to desert and disperse, released of the extreme external pressure the surface layers are easily expelled at a furious frenzy, spreading a mist of dark matter as these critical mass fragments (containing millions of galaxies) hurl through space. Initiating a 3 dimensional geometrical lattice, isometric, homogeneous base that will permeate and immerse all matter and define the magnitude of the local universe with volume inflation. What are fundamental particles? Fundamental particles in essences are tiny matter structure called “dark matter” comprised of two or more quantum thermal units. Dark Matter is one of the predominate substances in the local universe, we cannot see it, it is non-visual, but we can observe its effects and presence as inferred indirectly through motions of celestial objects, Fundamental particles (fmp) represent 45% of all the matter in the local universe. The fundamental particles (fmp- and fmp+ comprise about 30 to 40% of all the DM) 95% are fmp- and the remaining 5% are fmp+. Neutral particles comprise about 60 to 70% of the dark matter. These percentages may change some what, as they are hypothetical. Why this disparity? The low percentage of positively charged fundamental particles provide effortless propagation. The remaining 95% non-conjugated negatively charged fmp cannot bind or form any macro matter. In some respects adopt a harmonic attitude, resting in an isometric, homogeneous fashion. How fmp- affect a black hole ? When dark matter is confronted with a periphery, as a mass with a coalescent influence that has achieved critical mass status and the dark matter is impuissant to permeate it than can be effortlessly coalesced. The Black Hole is now able to construct conditions to integrate all matter and form a region of space that has concentrated mass, as a result of the weight intensity and external dark matter pressure, objects cannot escape. The method used is quite ingenious. Harboring a powerful coalescent influence the B.H. captures the surrounding fmp* or dark matter. Thus the black hole embarks to draw on the lattice and all the galaxies and lesser matter integrated within. As the lattice is drawn in, all that is immersed in the dark matter e. g. planets, stars and galaxies are slowly accreted. With this continuous accretion eventually the black hole acquires astronomical dimensions. The maturity of this celestial giant is totally dependent on this non-visual dark matter. Should for any reason a rupture occur in the lattice, the external pressure and accretion will diminish and the result, instability and a critical mass breach followed with a BIG BANG. Can we detect dark matters that harbor such minuscule matter structure? I believe the plausible region to detect or observe dark matter (fundamental particles) is in the haze shrouding black holes, teeming and under pressure of opposing forces, one dark matter and two the critical mass of a black hole. Constrained by the lattice formation and having close to zero motion this (rest mass) has few options. Dark matter confined in continuously more crowded quarters will influence thermal conditions, and initiate a haze enveloping a black hole. The theory of everything. To understand the universe we must basically split the fundamental particle down to its fundamental building blocks. We might arrive at potential energy or the irreducible quantum heat unit. The term “fundamental particle” is used here to avoid having to invent new terminology. The term Quantum thermal unit* = potential rest energy (pre) = quantum heat units Dark energy What is potential rest energy? That is the stuff between the stuff we can not see. A description of potential rest energy; – - It is extensively neutral, and almost {no motion, no spin}, non interactive, non binding, contiguous, shapeless, long lasting and at half the thermal value or less of the fundamental particles (Dark Matter) In Astronomy, as in all sciences, one can detect an object in one of two ways: either by observing it directly, or observing the effect that it exerts on more visible bodies. The existence of potential rest energy (PRE) is almost undetectable because they harbor such incredibly tiny energy unit structure. Potential rest energy is a hypothetical generic term though not visible to our technology their presence is inferred by their influence on visible celestial bodies in the cosmos. There is a growing consensus in the astronomical community that most of the energy in the our universe is in the form of dark energy that I refer to as (potential rest energy) A more compelling argument for (PRE), Let us hypothesize, why not saturate the entire universe with PRE. and construct a single fluid medium. It is only logical to assume that the universe was created from a very few varying quantum thermal unit values. The evidence from observations of the universe point to everything as being influenced by thermal information. At this point in time cosmologists don’t know what PRE is. With understanding the movements of celestial objects, great strides can be taken in the comprehension of the universe. The nature of PRE and its abundance, are crucial questions in modern cosmology. Since an insignificant percentage of all matter is visible, it is therefore logical to assume the possibility that these nonvisual constituents will determine the type of universe and how it performs. Potential rest energy and dark matter ubiquitous and very efficacious, what fundamental synergy do they posit? The deeper we delve the more intriguing we find this hypothesis of complexity wrapped in simplicity. This potential rest energy is found not only in space but contiguous with macro and dark matter in every facet of thermal interaction. Why such an abundance of these two ingredients in “the local universe”? One player in possessions of 52% of the total energy and the second about 45 % + as dark matter. This begs a question; Why are the galaxies not falling in on themselves? In order to proceed from this point can we posit bouyancy of all macro matter as a theory and assume that the universe is a quiescent fluid. This assumption that little conduction of energy and almost no viscosity maybe questionable on small scales but taken as a unit, the universe under observations behaves very much like a quiescent fluid. This causative agent is emerging as key factor to revive the “cosmological constant theory”. The existence of potential rest energy as a dominant basic constituent of the “greater universe” revives Einstien’s discarded hunch of the “cosmological constant”, maybe not exactly as he envisioned. Nevertheless this mysterious force is welcome news, it is highly improbable that a local universe will expand and turn us into dark matter nor will it collapse and crush us but possiible. This energy force assures us that omega one and the 3 D shapeless Greater Universe is equal. With the emergence of potential rest energy a draft guesstimate of the universal total volume of these three constituents (pre +dm +macro m) = (omega) to determine its size now is a possibility. I assume without proof that the universe is the same volume now as it was x trillion years ago, as being self-evident. What would be a logical cause that follows physics for expansion or loss of volume if energy can not be destroyed or created? The conjecture that the universe is infinite would postulate the genesis of matter as a hypothetical, potential generating thermal value units would be spread far too sparse to coalesce. not a viable option. Potential rest energy is the first order (in value?), more stable and long lasting than dark matter particles. As a first magnitude in size they are unable to accrete or transmit thermal information and this inability renders them ineffectual to expansion or contraction. I would prefer to call them potential rest energy,I extrapolate their existence as quiescent,almost zero motion and these contiguous constituents fill all space and permeate all matter. With domination of 67 % of energy in the Greater Universe may posit a thought. Is expansion or contraction possible with (32 % of dark + 1 % macro matter of the local universe) as active constituents of a Greater Uninverse?. Can the rearrangement of matter structures be absorbed into a cosmological constant of the Greater Universe? As humbling as it may sound these expansion theories may be regarded as regional phenomenons, as we observe regional generation and atrophy of galactic cycles. We may not even have ventured outside of our sector which commands at least 15 to 20 billion light years omni – directional. What does that say about our sector are we the new kid in the neighbourhood? Light like sound or water for propagation of motion needs a medium to transfers thermal information (energy) from the source. Potential rest energy being the first order of magnitude in size and unable to accrete thermal information this inability to transmit information renders them ineffectual. This may limit our ability to view light from our sector of the Greater Universe only. The fact that parts of the universe do display expansion does not proclaim that the universe can not be static. Dark Matter What is dark matter? dark matter is the stuff between the things we see. In Astronomy, as in all sciences, one can detect an object in one of two ways: either by observing it directly, or observing the effect that it exerts on more visible bodies. The existence of these fundamental particles maybe undetectable as they harbor such minuscule matter structure. Dark matter is a generic term for these fundamental particles in the local universe. Despite the fact they are not visible to our technology, their presence is inferred by their influence on the more visible celestial bodies. Their exact form maybe controversial but they do emit and accrete thermal information omni- directional and when favorable conditions present themselves they will illuminate. There is a consensus in the astronomical community that most of the mass in the our galaxy and of most galaxies, is in the form of dark matter. Let us posit a more compelling argument for dark matter: Let us assume as a hypothesis and permeate the entire mass structure including the whole of the local universe all inclusive with fundamental particles, and create a contiguous information transference medium. It is only logical to assume that the greater universe was created from a very few value varying quantum thermal units. As the evidence from observations of the universe point to everything as being influenced by thermal information. At this point in time cosmologist are dubious as what dark matter is. With understanding the movements of celestial objects, great strides have been taken in the comprehension of our local universe. The nature of dark matter and its abundance, are crucial questions in modern cosmology. Since an insignificant percentage of all matter is visible, it is therefore logical to embrace the possibility that this non – visual dark matter determines the type of local universe and how it performs. We may speculate as to what percentage of the local Universe is dark matter, whether galaxies and all macro matter contribute 1% or 10% the fact is 90 to 99% still remains dark matter and potential rest energy as quantum heat units. Dark matter is a combination of two varying fundamental particle flavors, a negatively charged particle and a neutral particle. In order for neutral particles to exhibit thermal (gravitational) influence they must possess mass. To be instrumental in the construction of plasma, neutral particles must rest in an adjacent formation. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume and implement a route for universal thermal transference. The second is a negatively charged particle (fmp-) ingeniously choreographing an isometric, homogenous three-dimensional geometrical lattice, These fundamental negative particles immersed in a neutral plasma assist in the creation of a thermal transference medium and restrain separation by avulsion of celestial objects throughout the local universe. This assemblage of particles immersed in these plasmas represents 100% of all matter in the local universe. One % seems more likely to represent the propagated macro matter occupying the greater universe. How can we detect dark matter? I believe the plausible region to detect and observe dark matter (fundamental particles) is in the haze enveloping black holes, here teeming between opposing forces, dark matter impuissant to permeate the critical mass. Constrained by their lattice and plasma formations and having close to zero motion this rest mass has limited options. Dark matter finding itself condensed to more than a normal comfort zone, this higher concentration of baryionic and dark matter will influence higher thermal conditions and initiate a haze around the black hole (as stated in the 1st law of motion). The haze should be brighter around mature black holes, as all thermal information is confined locally in the lattice to its periphery. The periphery will be determined by the rip in the dark matter (fmp- & fmpn). We may extrapolate that the enveloping dark matter density and unbalanced forces will determine (as stated by the 2nd law of thermodynamics) the thermal values surrounding black holes. Here we may encounter one or more problems– 1– Mature black holes should be totally invisible, isolated by a global moat of potential rest energy. Caused by a rip in the lattice. 2– Thermal information (light) is torpid and can not be transmitted to earth through a “void, vacuum or PRE”. To postulate, without dark matter as a transfer medium light can not be visible from the source. This phenomenon a lattice and plasma will construct sectors as independent areas bearing celestial objects as bubbles in the greater universe. (details Big Bang) Each resembling a small universe within a larger universe. IF one could view these bubbles, from a perspective point, one would perceive these sectors of the greater universe as floating buoyant bubbles throughout a fish bowl full of water. Black Hole Big Bang or Inflationary theory The origins of a black hole. There are good reasons to think why vast areas of super concentrated baryon matter exist. While not being subject to their physical existence of certainty, we can by rationality present a philosophical foundation for science and evolutionary trends, as proof by logic and reasoned pursuit of the senses. Black hole friend or foe? Black holes is a misleading catchphrase for these enterprising celestial paragons found in “minor universes”. Though branded as space behemoths methodically sucking sectors dry, these black holes of destruction may not be so bad after all. Perhaps these elusive cosmic entities will add credence to the theory that massive black holes are intricately related in the creation and evolution of minor universes, galaxies, stars, planets and all the lesser baryon matter. Black holes are high interest players in the composition of “minor universes”and their continued existence, by regenerating multitudinous sectors in continuum. Therefore prevent a high probability of creating any one major crunch and recycle at lower magnitudes, thermal information with lesser “big bangs”. There are various reasons and not surprising why we receive so little or no thermal transmissions from these elusive entities. 1— A Black Hole is enveloped while celestial bodies are permeated by the dark matter and potential rest energy. 2– Mature black holes should be totally invisible, isolated by a global moat of Potential rest energy (PRE*). 3– Coalescing and agglomerating, emptying space of both dark matter and the celestial objects within, leaving only quantum heat units (PRE), therefore rendering thermal transfer impossible. 4 —Thermal information (e.g.light) is torpid, and can not be transmitted to earth through the “PRE”. I declare without proof, lack or void of dark matter as a transfer medium, light will not be visible from its source. How are Black Holes constructed? Spinning stars or galaxies permeated and emersed in dark matter and PRE fields or matrixes establish a whirl – like motion, unlike a black hole these whirlpools do not initiate a central coalescing influence to the DM including the orbiting baryon matter. When dark matter is confronted with a periphery, a mass with a coalescent influence. that has achieved critical mass status and the dark matter impuissant to permeate this high density mass, at this state fundamental particles are effortlessly coalesced. The Black Hole is now able to construct conditions to integrate the fmp along wirh the more complex matter, and create an expanding region of space as a concentrated mass. As a result of weight intensity and dark matter pressure, objects cannot pull away. The method used is quite simple. A spinning black hole being a high density mass can NOT be permeated, it likewise establishes a whirl – like motion WITH central coalescing influence, both to dark matter and all the orbiting galaxies, stars, planets and lesser baryon matter. Harboring a super critical mass structure the B.H. assumes the role of host to all the surrounding fmp* and macro mass, while excluding the PRE. The FMP- is in the form of a 3 dimensional geometrical lattice that pervades the entire sector. The fmpn (neutral) is in a form of a plasma that pervades the entire sector, that presently is not occupied fmp- or fmp+, in concert fmp- and fmpn permeate the minor universe all inclusive. The natural state of fmp is to permeate all matter and the local universe all inclusive (Black Hole is excluded), this creates an equilibrium and / or buoyancy to the local universe and all celestial bodies within. Dark matter reacts differently when faced with a critical mass, the fmp can not penetrate this mass. The cause and effect results as a push pressure (we interpret as gravity) onto the mass surface. Fundamental particles on contact with the B.H. surface are transfixed by dark matter pressure and transfer the task to the next set of fmp, only to experience the same fate. As more and more dark matter is coalesced it gradually draws in the planets, stars and galaxies. If for any reason, the lattice was to rupture, coalescence would endure a deathly blow, and limit the process of gathering matter to form a more massive B.H. As long as internal pressure is in equilibrium with external pressure or internal pressure is less, the Black Hole will continue to coalesce. Once internal pressure exceeds external pressure, destabilization and critical mass breach will commence. To create a Black Hole by accreting these minuscule particles, one particle adjacent to the next is a labor of patience. Dark matter pressure collocate, agglomerates and concentrates this mass (dark and baryon matter). With each new addition is an increase in volume. The mass exerts extreme pressure to the specific particles, as a result of this successve pressure the specific units eventually alter their shape, consequentially evict all the Potential Rest Energy units (PRE is the stuff between between specific particles). It is the specific particles and dark matter that are creating this celestial critical mass phenomenon, a sequence that continues for billions of years*. (Time not as a dimension but as expressing a repetitive sequence of events). Throughout this evolution, stars, galaxies are bit by bit drawn / pushed by dark matter to the black hole. Since dark matter represents 33% (+ -) of all matter in a local universe, it is logical to assume the black hole is in possession of an enormous fmp force, countered by an external pressure of equal value. If for some reason the fmp- lattice and fmpn plasma are severed: Gradually matter around the black hole will deplete and expend it’s external pressure. This can lead to but one conclusion, the pressure from without spent, critical breach and an unstable black hole is imminent. What caused a Black Hole to fragment and not atomize? I believe critical mass and a strong coalescent influence orchestrates this foundation , condensing matter under extreme weight intensity compress the fundamental particles so tight as to altered their shape, evict any PRE (the stuff between the particles), condense and form a super critical mass. Although fundamental particles are primordial elements and will not break down, still they can not refuse the intense pressure and must adopt a polygon of forces, a new spherical form. These veins I am about to introduce are not visual, only exist as particle content. I propose this is the baryon matter now fmp-, fmp+, fmpn (neutral) 3 flavors truly homogenous matter to the eye. I realize for a human to travel to a high density stars such as black holes, descend on a cross section to observe these vast areas is impossible for a number of reasons. But as friut of the mind, here we are, upon closer observation we detect the plain to be non homogeneous. We notice countless marble like trails the archaeological remains of once, planets, stars, galaxies, and clusters of galaxies, now mere spots sprinkled throughout this surface. Massive layers of fmp- and neutral plasma. dwarfing the total baryonic matter content now sprinkled as minor trails forming a marble like effect throughout the Black Hole. Reasons why these veins exist are — 2 – With the vast distances between celestial bodies and the high ratio dark matter verses baryon matter, dark matter will be the prominent mass structure. This high ratio dark matter verses baryon matter allows DM the opportunity to blanket each macro mass as it is coalesced. Patiently these celestial bodies produce the vein effect throughout the black hole structure. These varying flavored veins eventually will form the fault lines in the Black Hole’s construction. With pressure spent from external sources, these veins now under extreme conditions will cause the black hole to fracture. The first break will stem where the greatest pressure is concentrated, producing the largest primary fragments. Each next generation explosion will be fractions and they inturn will fragmentize at their weakest links. The fact that galaxies are receding*, in all directions is a consequence of these initial explosions. and supports the theory that fragmentation, was the initial matter structure of our “local universe”. Thermal expansion with super high temperature of each fragment was achieved in the final stage of fragmentation as critical mass was breached. Is a Black Hole. hot or cold? With the introduction of these various thermal values, dark matter (low) and celestial objects (some very high) describes the state of this system. Dark matter being 28% to 32% of cold matter and macro matter 1% to 5% hot the overall temperature will be low. Within the criticle mass the motion of particles assume a rest mass state and are transformed to potential energy with all PRE expelled. The internal energy might be thought of as the tendency for all matter in the black hole to evolve toward a state of inert uniformity, or potential matter at rest.,br> At this present state the 2nd law of thermodynamics has met its Waterloo. Equilibrium can not be achieved, what we have are fundamental varying values. Does this leave with perpetual motion? Question in my Mind? What is weight? In space is one cubic inch of black hole matter heavier than one cubic inch of a star or cubic inch of air? Why do they not fall? fmp* = fundamental particles (The term “fundamental particle” is used here to avoid having to invent new terminology) PRE* = Potential rest energy = Quantum thermal units = Quantum heat units. Time = Something perceived by our senses. Critical* = high density held in check by dark matter pressure Central coalescence* = drawing to the centre BIG BANG Big Bang or Inflationary theory Imagine a local universe as a constituent of a “greater universe” a closed system, its internal function intrinsically is thermal administration. Science has shown beyond a reasonable doubt that our universe did in fact have a beginning. In reference to the Big Bang, this theory additionally posits reasonable effort to explain what happens to any minor universe at its origin. Essentially a Big Bang is inflationary but the greater universe did not originate with a big bang. The Many Bang theory exhibits a regeneration and distribution of matter in all minor universes as constituents of the greater universe, precisely what we should expect from continuous “big bang” eruptions. If one could view from a perspective point the greater universe, it would appear effervescent in relation as to what we observer as a chaotic existence. Each big bang eruption is responsible for numerous fragments, soon after super inflation. these hot masses will eventually form future planets, stars, galaxies, clusters and all the lesser matter. Each time a big bang occurs, matter fragments are cast out omni-directional. Over time* fresh black holes are created, re-coalesce the fundamental particles,planets,stars, galaxies, the result of this course, a new Big Bang. Essentially when we refer to big bangs, we are referring to eruptions in a local universe a sector of a Greater Universe. The inflation theory states basically, all of the matter in this particular sector was already present, and attempts to explain, how and what drove this sector into a period of chaos and hasty expansion. This hypothesis extrapolates that the Big Bang can not be the origin of the greater universe but that black holes are one cause for perpetual contraction and expansion in “minor universes”. The big bang undergoes a number of stages, immediately after critical mass is breached. The black hole fractures into a number of large fragments, casting them randomly omni-directional. The second phase breach repeats this process, each chunk fragmenting, casting smaller fragments every whichway. This is repeated numerous times, eventually coalescent influence is sufficiently weakened, exploding these fragments, unleashing enormous thermal expansion and releasing what once were stars, galaxies and clusters of galaxies. At that moment this “local sector” is chaos, confusion, fundamental particles and super high temperatures. What kept these fragments in a critical state? A thick outer crust of negative and neutral fmp envelop each critical mass fragment. This crust empowers these fragments the opportunity to penetrate deeper into space before they super inflate. We should note the gigantic sizes of these fragments, each containing many millions of galaxies. Some of these fragments may range a light year in diameter. With each additional stage lesser fragments and weaker external pressure will influence the final state. With dark matter pressure weakening, fundamental particles are now able to discharge and permeate space. Laying a foundation for a 3 dimensional geometrical lattice and plasma while simultaneously producing a time delay effect, allowing these fragments to hurl deeper into the greater universe. With the gradual release of dark matter pressure the critical mass coalescent influence sufficiently weakened, they will explode, again casting lesser fragments every whichway. This process is repeated until all the critical mass (potential baryonic matter) that is trapped within these fragments reach their final stage. With coalescent influence almost exhausted, internal pressure now exceeding external pressure, only now can the potential baryon constituents within initiates thermal superinflation. Expanding to galactic proportions converting the mass into an enormous amount of thermal energy in microseconds*. But not before these fragments were cast at speeds beyond my description, seeding space with countless galactic thermal clusters. Confusion, fundamental particles and chaos reigns. Time* = something we perceive through our senses, UNIVERSAL EXPANSION What is Expansion ? A General Theory of Relativity should predict that a local universe is not static, as observations confirm this, indicating that it is expanding. It must be remembered that the Big Bang represent the creation of a minor universe. This event marking a beginning suggests, the minor universe must have been much smaller at its inception. The Big Bang should be pictured as a big explosion somewhere in space with fragments being cast out omni directional from an exploding mass, known as the Big Bang, This does not mean that the galaxies and lesser objects are flying out into space infinitum, the fact is, relatively very few bodies do, eventually galaxies lose all velocity. As temperatures decrease, planets, stars, galaxies evolve and acquire spin, orbit and adopt a buoyancy state, as matter at rest. What it does suggest is, matter in space is becoming dispersed, diffused, spread out and in so doing, it increases fundamental particle content in space and the distance between celestial bodies. How does this effect man? We are living in the most intriguing time, in a universe like nothing we imagined just a few short years ago. A hypothetical such as, is man expanding or contracting by some mysterious force were curiosities of fiction. Living organisms are not noticeably subject to this phenomenon of universal expansion; the dark matter (DM) permeating our body is of higher thermal value in comparison to DM in space.(ok so!). Our planet is continuously and simultaneously supplied and depleted of thermal energy, contraction will effect matter of the higher thermal content first and translate as a decrease in fmp* structure (diameter) and specific* particle content. Here we may apply the Second Law of Thermodynamics. This law claims that “Energy spontaneously tends to flow only from being concentrated in one place to becoming diffused or dispersed and spread out”. As long as our planet compensates our thermal value, we will not feel any noticeable effect , and dark matter will absorb energy from the higher thermal emitting matter (E.g. galaxies, stars, earth etc.). When considering universal expansion we can only observe what we can see. Suppose we observe the stars in the outlying universe, and suppose we observe idiosyncratic mannerism of everyday matter, can we structure common inherent properties. Assuming the universe, galaxies and all the matter on earth are permeated * by dark matter particles, can these idiosyncratic phenomenon in possession of these structural and behavioral characteristics apply a logical postulate? There is a consensus in the astronomical community that most of the mass in most galaxies is non-luminous dark matter and those celestial objects in space and matter on earth are analogous. I refer here to Dark matter as a generic term for these fundamental particles in the universe though not directly observable, they do permeate all matter and fill all space with their presence as inferred by the motion of galaxies. Dark Matter particles absorb contiguously and omni – directional thermal information from higher energy sources (e.g.stars). Hypothetically one may extrapolate an increase in thermal content will increase the structure of the fundamental particles (DM) likewise increase the content of specific particles in the region and interpret this as increase in the local universal volume. If this assumption is valid than our Sun’s thermal information (energy) lose, should express a constant increase to earth’s orbit. fmp * = fundamental particles (The term “fundamental particle” is used here to avoid having to invent new terminology) permeate* = 1 The fmp- form a 3 dimensional geometrical lattice, isometric, homogeneous, permeate and immerse all matter and assist to define the magnitude of the universe with their volume inflation. Permeate* = 2 The neutral fmp is instrumental in the construction of a plasma; neutral particles must rest in an adjacent formation. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume and implement a route for universal thermal transference. Specific particles* form baryon matter. Gravity Fish swim in water; birds fly in air, why can’t celestial objects float in plasma? Does symmetry affect gravity? The emphasis on the interaction and understanding thermodynamic functions of a system becomes indispensable as thermodynamics continually uncovers particles with lesser mass value. When dealing with fundamental particles a hypothetical approach must be applied to emphasize the interaction between particles in modern physics. Such particles can only be observed by their influence on celestial objects, galactic systems and by reasoned pursuit of our senses. Thermodynamics for example, must apply hypotheticals to deal with the measurements of minuscule elements, as our modern technology simply can not deal physically with these non – detectable particles. What is Symmetry? One definition of symmetry might be: Preserving a distance of elements at given points in space. This hypothesis of symmetry has led to deeper understandings of fundamental particles, inspite of absence of physical evidence to the extent of certainty, and by rationality we may present a philosophical foundation for science, as proof by logic and by reasoned pursuit of the senses. Under closer observation logical postulates should infer that symmetry may exhibit variations between fundamental particles and not be as homogenous as we may have generally believed. Symmetry infers given a set of points, each fundamental element or particle has its own point in the universe and describes symmetries in the construction of matter, matrixes or force fields. Gravity here is a term used to identify thermal transfer, a force that exerts contiguous* influence between particles throughout the entire structure or local universe. In order for particles to exhibit (gravitational) influence they must possess matter and in order to be instrumental in the construction of thermal transfer (gravity), must rest adjacent. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume and implement a route for thermal influence. This isometric homogenous assemblage of particles (fmp-, fmpn (neutral) and potential rest energy*) can present an illusion of a string theory as some theorists have hypothesized. In reality it is the transfer of thermal information that effectuate these links. Negative fmps are minuscule matter structures with a thermal charge or flavor. Ingeniously they choreograph an isometric, homogenous three-dimensional geometrical lattice and each particle occupying a tiny segment of the “local universe”. Synoptically set up in a geometric formation from which they can not diverge. Each fmp- and fmpn can contiguously impose a CONSTANT and WEAK thermal (gravitational) influence throughout the entire local universe via this dark matter. Upon closer observation we will find, there are two types of mass in motion. 1: Independent motion. To postulate an independent celestial mass with motion does experience drag from dark matter in the local universe. This drag does create a reduction in mass velocity, as stated in the Second Law of Motion. Any accelerating mass as determined by second law of motion would meet with increased resistance from dark matter to any continuing increase in speed. To postulate that mass possesses thermal (gravitational) influence that is hardly hypothetical. What has been missing is the notion of a medium to branch local universal unit motion and drag, which together can describe with immediacy–gravity, inertia, and their identical nature. 2 : Is the most prominent class which include galaxies, stars, planets, these are predominantly static buoyant bodies. We may likewise assume that buoyant, spinning celestial mass does experience ( minor) drag from dark matter in the local universe, while maintaining a uniform motion. A drag does cause a reduction in orbital progress of the mass, as stated in the First Law of Motion. With little drag the DM and the mass will remain relatively in uniform motion, Both DM and mass moving conjointly as a unit, mass will bifurcate from its orbital path at varying velocities. With an inherent tendency for fmp in the universe to evolve toward a state of inert uniformity following logic, the 2nd law of thermodynamics at this state is in refute. As the first law of quantum thermal unit rearrangement states: No two quantum thermal units can share the same point in space. To thoroughly digest the” quantum thermal unit rearrangement” concept, we should start with a proposition. What is the mechanism to explain this function and extrapolate a quantum thermal unit rearrangement theory? Like sound or water for QTUR propagation, a contactual contiguous fluid like medium to fill the total volume is required. Sequentially vast quantities of quantum units are needed to simply fill this space. Let us posit a novel argument for general behavior and causation of these basic constituents. These varying values of PRE influenced by the 2nd law of thermodynamics eventually form baryon particles and advance to more and more complex matter but do not increase their unit value nor do they increase the volume of the greater universe (1*). These new binding particles simply displace PRE units and resultantly claim that space (2*). These new particles now in possession of thermal transfer, initiate motion by thermal transference but the number and overall volume of the PRE units remains a constant. What we are witnessing is a local coalescence of binding particles or formation of baryon matter. An increase of quantities of specific units in an expanding* local region only. Hypothetically we may extrapolate; each one cubic inch of space will contain (+ – *) the equal number of pre unit. Like wise each cubic inch of dark matter, inconsequential as to the type of baryon matter will contain the (+ -) the same number of PRE units. Dark matter in possession of these essential fundamental interactions (e.g.gravity or thermal transfer) as stated in the second law of thermodynamics will exert limits to regional (e. g. local universe) expansion and contractions by thermal interactions. To hypothesize that gravity is a transference phenomenon , hence these particles must possess the ability to transmit information contiguously uninterrupted throughout the lattice via the plasma. (Except in PRE* pockets) where near zero transference will occur. Establishing the entire volume of the local universe with a gravitational influence to the periphery. My hypothetical proposal is that gravity (plasma) is the enthalpy that introduces thermodynamic transference capabilities to the fundamental particles. The fundamental significance of these three basic elements, positive, negative and neutral on their own are quiescent, but! To hypothesize, positive immersed in neutral plasma will configure a positively charged fmp, now in possession of thermal transfer capabilities. A negative immersed in neutral plasma will configure a negatively charged fmp in possession of thermal transfer capabilities. Immersing (fmp+and fmp-) in a neutral plasma, a new element is configured that precipitates aspirations to propagate. This significant new element introduced (fmp+fmp-and fmpn) now is in possession of thermal, (gravity) and coalesences capabilities (first baryon particle). The gravitational transference in its essences is a derivation of life. If so these alpha particles are fmp positive, fmp negative, and fmp neutral are three varying flavors. GRAVITY is a thermodynamic transference requirement of an internal energy system to function. The administration of the thermal energy is called gravity. Contiguous* meaning gravitational influence is transferred from one particle directly to an adjacent fundamental particle. PRE* potential rest energy = quantum heat units = quantum thermal units. Gravity* is hypothetical a term referred which is thought to exist and represents the conventional theories to an essential cause (or source) of gravity. (1*) —- By “do not increase their unit value” is a reference to, they continuously retain the same size (volume) and thermal value. (2*) —- By “particles simply displace PRE units and resultantly claim that space”.—-. Meaning the coalescence of binding particles obey the laws of QTUR, that states no two quantum units can share the same point in space.The 2nd law of thermodynamics achieves the coalescence of two or more quantum thermal units (pre), they themselves do not contain any smaller components Each pre unit continues to retain a constant value as a more complex composition is being constructed..The total value of the complex composition is the sum of the total number of pre units and their total respective values. Binding units (a composition of two or more pre) expel any non binding PRE units and claim their points in space. Those expelled and unable to accrete thermal information simply claim the space left vacant by the prior occupants. Thermodynamics Thermodynamics is the science that deals with temperature interaction between all particles and an introduction to variables that describes the state of a system governing the basic principles of temperature ,entropy and enthalpy. In adopting the macro point of views we assume the system will transfers down to the micro level and lower still to the fundamental particle state and beyond. Following the natural laws of physics, value can be assigned without visual knowledge of these particles; their presence can be measured by pressure, temperature or by observing the effect that they exert on more visible objects. Heat and energy are two magnitudes of the same physical thermal nature a spectrum of thermal motion. The varying degrees of probabilities in this entropical spectrum represent also human life as a frequency range of this thermal spectrum of motion. We can extrapolate that thermodynamics in general activates every phase of particle, biological and human experience. The first law of thermodynamics is a straight forward law of physics in a “closed system”. In order to proceed from this point can we assume as a theory that the universe is a quiescent fluid. This assumption that little conduction of energy and almost no viscosity maybe questionable on small scales but taken as a unit, the universe under observations behaves very much like a quiescent fluid. If Potential rest energy is the first order in value, and as a first magnitude in size they are unable to accrete thermal information and this inablity to transmit information renders them ineffectual to expansion or contraction and (pre) will impose a periphery. This thermal influence may create a temporary closed system on this sector and the matter it may harbor. What would be a logical cause that follows physics for expansion or loss of volume if energy cannot be destroyed or created? The conjecture that the universe is infinite would postulate the genesis of matter and a closed universe as a hypothetical, potential generating thermal value units would be spread far too sparse to coalesce. An infinite universal system is not a viable option. The term “one” as the total “universe”, postulates that you can perform any real physical process and remain with as much energy as you had to start with “in the closed system”. This implies perpetual motion is possible. The second law asserts energy is transferred from higher thermal system to a lower thermal system to achieve equilibrium. If we recognize these as sectors of the “one” the quantity of energy remains with zero loss. The thermodynamics of a b.h. is to create an enthalpic environment the equivalent to the sum of the internal energy of the system in equilibrium with the total product of its volume and a homogenous temperature. A function unobtainable by the pressure exerted on the black hole by macro and dark matter. The introduction of these various temperatures dark matter (cold) and celestial objects (some very hot) describes the state of this system. Dark matter being 33% of cold matter and macro matter 1% hot the overall temperature will be low. Within the critical mass the motion of particles become a rest mass and conservation of energy is at a very high degree of efficiency. The internal energy might be thought of as the tendency for all matter and energy in the black hole to evolve toward a state of inert uniformity, or potential energy. The haze (Cold+Hot matter = K?) surrounding BH implies that thermal value does impose internal stress amidst potential energy and the continued restraint on forces binding this mass. Natural origin of life Intro to life The mere fact that consciousness exists, we can create and continually evolve consciously for the good of others is astounding. Not surpassing that our definition “what is life” is subjective, prejudicial and not aspiring to objectivity? To observe the Homo sapiens curiosity and aspirational goals shackles our task to tackle this question. We need to understand the natural sources of energy and what forms of energy are involved in life processes. To define life, a solution to this problem requires knowing something about our ancestor’s characteristics. We can safely infer all varieties of life appear to have a common factor, or common ancestry. One readily apparent commonality is, all living things consist of similar organic compounds. This pool of common compounds binds us to a common ancestral history. How do molecules communicate? This theory has very significant implications to create living organisms from inorganic materials, It follows logic to suppose that out of the simple particles, a fundamental theory, which unifies and interrelates all matter that possess information transfer capabilities. We know present day life depends to a large extend on, e.g. sugars oxygen and solar energy. If molecule requirements are to assume the concept, that information transfer is a condition for life, this infers all particles in possession of info. transference, thermodynamics and gravity meet the required conditions If life consists of fundamental matter, it stands to reason that origin of life may essentially originate in a thermodynamic fundamental state for nonorganics Can information transfer occur in dark matter in a thermodynamic state? Since all matter possess characteristics of information transfer, defining life type depends on the energy transfer rate These fmp the most basic of matter must also follow the laws of physics. These fmp- form a three dimensional geometrical lattice immersed in a graviton plasma and inhabit the entire cosmos, constructing a constant and reliable transit avenue, capable of info transference and allowing molecules to transmit information intercell. The close proximity to each other and their size makes them ideal to assist in building more complex molecules, and the most advanced intelligence. When did life begin Some scientist believe that life was introduced to earth by comets, meteorites, space dust, all this is possible, but really this is beside the point. Life in basic or more complex form must be a very common commodity. If we assume that information transfer is common, this implies that life exists throughout the universe. If information transference is a basic component of matter, the most primitive basic life must be a mechanism for more complex building blocks. The conditions will determine the complexity of molecule development and determine the degree of information transference. When particles bind information transfer is communicated to the recipient and confirmation is acknowledged The message can be simple in basic particles, more complex in higher forms, e.g. amino acids and more advanced molecules capable to replicate, or pools of molecules (e.g. humans). Molecules and man, which comprise of living cells, individually obey the laws of chemistry, physics, laws of thermodynamics and governing the relationships between different degrees of energy. These laws of physics apply to the whole universe. If Cairns-Smith is correct, creating primitive evolving physical systems may be fantastically simple – and indeed is forming continuously all around us A logical assumption infers that all commodities have a function, in a chain like phenomenon in the cosmos puzzle. My question is What is the aim of black holes? Are they necessary? They surely must be, they have survived and exist. The black hole accretes all matter, concentrates fundamental particles, and may precipitate conditions favorable for thermodynamic propagation. Our universe is constantly changing; this process would be unnecessary if matter or energy could not be created. Life is not created by random rather the type of life is dictated by thermodynamic conditions and defined, as matter which uses energy flowing through a system, resulting in increasing and developing complex replicating communicational transfer matter. Logically we should assume that the theory of communication transfer has existed since the day the charge was introduced to matter. To me communicational transference appears to possess characteristics relating to gravity. The complexity of molecules depends completely on conditions of thermodynamics. It seems the more complex the molecule is, the more energy it consumes to sustain its existence. Clearly our life system is codependent on external energy source, e.g. earth, sun and dark matter. Can physics predict whether life phenomenon can be reduced to a fundamental matter theory? If so considerable success can be achieved in understanding the structure and organization of stellar systems in terms of gravitational forces, non-living matter in terms of electromagnetic forces, and thermodynamics in terms of information transference. All matter answers to the same laws of physics. When matter at different temperatures are allowed to integrate, a physical change in their composition occurs. With favorable conditions a new rearrangement of particles can appear (regarding to B.H.) index LIGHT The Nature of Light The origins of light has captured the imagination of many scientists since the inception of hypotheticals, as to what is the mechanism to explain the function and extrapolate a theory of light. It has been established that light transfers thermal information (energy) from the source. Light like sound or water for propagation of motion, needs a medium. Light is a thermodynamic function with internal interactions of emission, accretion and exerts energy units (quantum units) on this medium (dark matter) Assertions postulated that light characteristics are corpuscular or waves, ignore the possibility that the nature of light may be a contactual transfer phenomenon of thermal information. Argumentation initiates some theories as questionable, as they are void of a medium to transmit thermal information. This is where the concept of fmp (fundamental particles or dark matter) affirms a viable medium. Dark matter is a combination of two fundamental particles a negatively charged particle and a neutral particle (graviton) To be instrumental in the construction of plasma, graviton* particles must rest in an adjacent formation. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume (the cosmos) and implement a route for universal thermal information transference. For now I will refer to this interaction as palpitation indicating actual momentary disturbance in the medium. Emersed in this plasma (Dark Matter) is a concept of contiguous fundamental particles that transfers thermal information (light) contactually, implementing an omni – directional emissionary and an accretionary interaction. The theory of light dispersing is logical; it provides an interaction of the spectrum with omni – directional dispersed light and various thermodynamic values. If we can accept this as a logical hypothesis than dark matter is this medium. We should question this phenomenon; can thermal information survive in a vacuum or a PRE plasma*? How can a photon maintain energy levels in a hostile PRE environment? Starving for energy. The speed of light (frequency) is directly influenced by the value of the mass particles or varying thermal values applied to (varying mediums of varying values) will result in varying speeds. Light speed is finite for two reasons– 1– dark matter resistance will impose limits to transfer speed as Einstein predicted even though he was not aware of dark matter in this format. 2– second reason is thermal information accretion rate will impose limits aswell. 3– in a matterless space a (true vacuum) light will not survive. The rate of transfer (emission and accretion) in a medium is the velocity of thermal information transfer from one fmp to an adjacent fmp omni – directionally. To achieve light speed very little particle movment occurs only the contactual contiguous interaction of thermal information transference It may very well be that contiguous thermal transfer and fmp values produce conditions for said speed of light. The term “Light” in the common sense, is referred to as a is a limited portion of the spectrum, sensed by the human eye. Dark Matter particles absorb thermal information from the source and when this DM interacts with a medium of a higher thermal particle density content, this triggers illumination (fmp are indestructible to the temperatures of celestial bodies). Actions that propagate the speed of light is thermal information transferred omni – directional in the lattice. Absolute constant speed of light may not be intrinsic, as space would require homogenized omni – directional medium of matter. Will not happen. Light transfers thermal information contactually in an omni – directional emissionary and accretionary thermal interaction. This omni – directional process is emersed in a contiguous fmp plasma. ——————————————————————————– fmp * = fundamental particles (The term “fundamental particle” is used here to avoid having to invent new terminology) graviton*=The term is used here to avoid having to invent new terminology PRE * potential rest energy more on “dark matter” ——————————————————————————– created by Sam Sade, samsade@rogers.com last modified: june 10, 2003 index Shape of the Universe What is the Shape of the Universe? The shape of the universe can only be inferred from observation and theory. It is (logical?) to assume the universe is a 3 dimensional shapeless entity and we somewhere inside. The consensus of the astronomical community is that our local universe’s current radius is 14+ billion light years omni-directional. No matter what direction we gaze at, we see more or less the same density of galaxies. Implying that our sector of the universe may consist of a contiguous medium and as a (closed system?). Gaze out in any direction of the sky, and you get very similar microwave temperature readings. To extrapolate a theory from these constant thermal readings may imply curvature and apparently a need for a periphery. Suggesting that our sector of the universe structure is finite. What can be the mechanism to explain this function? Argumentation initiates many theories as questionable, as they are void of a medium to transmit thermal information. This is where the concept of dark matter and potential rest energy are perfect mediums to transmit and diffuse thermal information omni-directionaly and affirm viable mediums from where thermal information emanates. The universe is comprised of these constituents or flavors (fmp-, gravitons, macro matter and potential rest energy) 1 — the fundamental negative particles (fmp-) form a 3 dimensional geometrical lattice, isometric, homogeneous, permeate and immerse all matter and assist to define the magnitude of the universe with their volume inflation. Negatively charged fmp can not bind*, have no motion and rest as close as determined by their negative charge. 2—-the neutral (graviton) is instrumental in the construction of plasma, graviton particles must rest in an adjacent formation. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume and implement a route for universal thermal transference. Dark matter absorbs thermal energy from the macro mass e,g, earth, stars, galaxies etc. This thermal energy effects the content and /or expands fundamental particles effecting the amount of space occupied. The macro matter works in reverse it emits thermal energy and its volume decreases. Despite the fact that a local universal is expanding in this regard the Greater Universe remains static, as for macro matter (comets, stars galaxies etc) these have varying reasons for motion. Hypothetically matter or as energy this content in the Greater Universe is a constant and in possession of sufficient matter and the 3 dimensional shapeless universe will not increase or decrease in volume. Sectors in the universe continually collapse form black holes and inturn superinflate To define critical density, all macro matter and dark matter must revert to potential rest energy and achieve (almost?) thermal equilibrium. Except that….. Black holes are high interest players in the design of a local universe’s continued existence by regenerating various sectors in continuum. These elusive cosmic entities add credence to the theory that massive black holes are intricately related to the creation and evolution of galaxies. Black holes are constructed by conditions to integrate all matter and form a region of space that has concentrated mass They guard against high probabilities of any one major crunch, continually replenishing new thermal information with continuous smaller bangs. This phenomenon ensures that regional universes maintains 3 dimensional (1s and 2o)* shape I am averse to a flat universe, these theories present us with physical difficulties. Evidence around us suggests to the contrary, everything we visibly see tends to endorse a closed system. ——————————————————————————– Dimensions* —–1s = one sphere and 2o = two ovals Bind *—-Dark matter comprises of three alpha particles, a positive, negative and neutral. These fundamental particles represent 33% of all the matter in the universe. Macro matter comprises about 1 to 5% of the total macro matter in the cosmos the remaining 95 to 99% is referred to as dark matter. Fmp- and fmp+ comprise about 30 to 40% of the dark matter. These are divided again about 95% fmp- and the remaining 5% are fmp+. Why this disparity? With so few positively charged FM particles, this provides effortless propagation. The remaining nonconjugated negatively charged fmp cannot bind, have no motion and rest as close as determined by their negative charge. Their objective now is to form a 3 dimensional geometrical lattice, isometric, homogeneous, permeate and immerse all matter and with the aid of (graviton) plasma, define the magnitude of the universe with their volume inflation. index Does Earth have Headway Momentum ? ——————————————————————————– Copyright & copy; 2003 by Sam Sade, all rights reserved. This text may be freely redistributed among individuals in any medium so long as it remains unedited and appears with this notice Any commercial or republication requires the written permission of the author. ——————————————————————————– Our solar system presents us a wondrous adventure into the unfolding secrets of a star, its planets, comets, asteroids, planetesimals, meteors, dark matter and potential rest energy, as an oasis of motion. It is understood from the standpoint of our observations that no object in the universe is at rest. Every object is in a state of motion. The question is what is the functioning agent that initiates an object a process for changing a position in space? Motion in the universe is comprehensively interrelated through an internet of quantum thermal units (PRE *) and fundamental particle fields.* Objects with independent momentum are those that the First law of motion applies too. “Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it”. (Newton) What is this force? Hypothetically let us consider this unconfirmed force consists of three constituents: One is potential rest energy the basic constituent that pervades the “greater universe” or the entire space. While #2 and #3 are more complex constituents added to our local universe (a sector of the greater universe) e.g. for this exercise, let’s use our solar system. #2- Is a fundamental negative particle a constituent of dark matter that forms a 3 dimensional geometrical lattice, isometric, homogeneous, that permeates and immerses all matter #3 -Is a neutral or graviton particle also a constituent of dark matter that permeates, immerses all matter and is instrumental in the construction of a plasma. These graviton particles must rest in an adjacent formation. Sequentially vast quantities of contactual neutral particles are needed to simply fill the volume and implement a route for thermal transference. Why are orbits elliptical? A rotating orbital star emersed in “potential rest energy” and “dark matter” establishes elliptical fields entrapping all orbiting planets, comets, asteroids, meteors, planetesimals and including all space dust. One force is a mild PRE* field and a second sharing conjointly this matrix is a more dynamic DM field. Their rotation inconcert influence the fields to adopt a whirl-like motion, unlike a whirlpool it does not initiate a central coalescence to the whirling or orbiting matter. I believe the planets permeated and emersed in these plasmas are static buoyant bodies in elliptical whirl pool matrixes. Following logic we may assume a rotating planet immersed in PRE & DM fields will likewise establish a whirl pool and initiate local drag. In general planets do not possess forward momentum but rather express a static state. We may extrapolate that the interaction by the two fields (the sun’s and the planet’s) will retard the planet’s orbital flow and impart the impression of independent motion. In reality due to varying mass and local drag values, the planets project only an illusion of headway momentum. Our earth is not motionless; it commands one major independent motion, a spin as it orbits the sun (excluding minor motions) The earth’s spin propagates a divergent whirl pool in its matrixes and the consequence is resistance and or pressure on the solar MATRIXES* that in turn creates a drag to earth’s matrix* fields, imposing the minor axis to elongate and form elliptical fields. I believe the causative varying thermal values to dark matter locate the apogee of the semi – major axis facing the sun and perigee facing away This may beg a question; Our Sun as a member of the Milky Way is considerably the most dominant whirl pool in our solar system. Commands at least one motion as it spins and orbits around the Milky Way. Assuming the Sun does NOT command independent headway momentum, hence we may extrapolate the same laws that govern the orbits of planets around the Sun, must also govern the motion of stars. As the Sun orbits’, its solar matrixes** exert pressure onto the “galactic” MATRIX* fields, the consequential result once again is resistance and or pressure to the solar matrixes** with the “minor axis” forming elliptical fields to the solar matrixes**. While the Sun’s apogee of the semi – major axis will maintain facing the galactic center (or the higher thermal value) as the Sun advances in its orbit around the Milky Way. Assuming these same laws that govern the orbits of planets around the Sun also must govern the motion of stars. Based on this hypothesis, we may extrapolate the Sun to be buoyant and static is logical. The Sun must adopt the galactic orbit. To postulate that a planet commands orbital independent headway motion implies the planet’s speed is variable as it continuously orbits the sun. We than may presume in the process of its orbital progress it will encounter the need at least once to increase velocity as it tries to catch up to the sun’s orbit. This hypothesis is stressing logic and begs for a myriad of gravitational and mathematical inferences The origin of some of our (if not all) planets might be fragments hurling through space with just enough velocity to enter the sun’s elliptical QTU fields and not sufficient enough energy to escape and are captured in this eccentrically elliptical field The fragments crashing into the sun may extrapolate any number of theories as to the origins of ” planets and other matter”. If a fragment with sufficient velocity can pass through the elliptical QTU field it will continue into space never to return. (Never is not an infallible term but close) New Theory on Dark Matter By Rohit Sharma ABSTRACT Dark matter, proposed decades ago as a speculative component of the universe, is now known to be the vital ingredient in the cosmos, eight times more abundant than ordinary matter, one quarter of the total energy density and the component which has controlled the growth of structure in the universe. Its nature remains a mystery, but, assuming it is comprised of weakly interacting sub-atomic particles, is consistent with large scale cosmic structure. However, recent analyses of structure on galactic and sub-galactic scales have suggested discrepancies and stimulated numerous alternative proposals. We discuss how studies of the density, demography, history and environment of smaller scale structures may distinguish among these possibilities and shed new light on the nature of dark matter. The last decade, has seen the emergence of a standard model, sometimes called a “concordance model” (1) to emphasize that its predictions are in concord with current observations – both of the nearby universe and of the early universe as seen in the cosmic background radiation (“CBR”). The new CBR results (2) recently published by the team of scientists analyzing the observations of the WMAP satellite are generally assessed as providing a brilliant and comprehensive verification of the concordance model. But consistency or concordance is not scientific proof. The model works. And, many previously proposed models are now known to be wrong in essential elements. Most of the current work in cosmology is focused on pinning down the adjustable parameters in the concordance model to see how precisely we can specify that model and whether any discrepancies will appear as this process is advanced. History, however, is a stern teacher. We know that all physical models for natural phenomena represent approximations to the truth. The blinding light that seems – for the moment – to be illuminating our path is certain to expose stubborn facts that will cause us to modify and extend the current paradigm. First, according to the standard model, there is ordinary matter consisting of the familiar chemical elements. Nuclear cooking that occurred in the first few minutes after the big bang left a soup containing primarily hydrogen and helium and other light elements. Recent measurements of chemical abundances are consistent with theoretical predictions (3) – provided the mass density of ordinary matter is about 4% of the total energy density of the universe and from WMAP we now know that this estimate is accurate. But, we also know from various gravitational effects that the total mass density is much more than 4% of the total energy density. Over 65 years ago the Swiss astrophysicist Fritz Zwicky (4) noticed that the speed of galaxies in large clusters, such as the Coma cluster, is much too great to keep them gravitationally bound together unless they weigh over one hundred times more than one would estimate based on the number of stars in the cluster. Decades of investigation confirmed his analysis, and in the 1970s further evidence for dark matter It was found from gravitational studies of matter in the outer parts (the halos) of ordinary nearby galaxies (5, 6, 7, 8). By the 1980’s, the evidence for dark matter with an abundance of about 20% of the total energy density was widely accepted, although the nature of the dark matter remained a mystery. After the introduction of inflationary theory or the very early universe by Guth (9), many theoretical cosmologists became convinced that the universe must be flat and that the total energy density must equal the value (termed the critical value) that distinguishes a positively curved, closed universe from a negatively curved, open universe. Furthermore, noting how the evidence for dark matter was growing and extrapolating from the previous decade of study, the theoretical cosmologists became attracted to the beguiling simplicity of a universe in which virtually all of the energy density consists of some form of matter, roughly 4% being the ordinary matter and 96% the dark matter. In fact, observational studies were never compliant to this vision. Although there was a wide dispersion in total mass density estimates, there never developed any convincing evidence that there was sufficient matter to reach the critical value. The discrepancy between observation and the favored theoretical model became increasingly sharp. Finally, dark energy came to the rescue (10). The only thing dark energy has in common with dark matter is that both components neither emit nor absorb light. In all other respects, they are different. Microphysically, they are composed of different constituents. Most significantly, dark matter, like ordinary matter, is gravitationally self-attractive and clusters with ordinary matter to form galaxies. Dark energy is gravitationally self-repulsive and remains nearly uniformly spread throughout the universe. Hence, a census of the energy contained in all the galaxies would miss almost all of the dark energy. So, by positing the existence of a dark energy component, it became possible to account for the 70-80% discrepancy between the measured mass density and the critical energy density predicted by inflation (11, 12, 13, 14). But the dark energy dominated models make a strong prediction – that the universe is currently accelerating, due to the gravitational self-repulsion of the dominant dark energy component. This ran contrary to the then-current best observational tests based on the brightness of distant supernovae. Then, two independent groups (15, 16) found evidence of the acceleration from observations of supernovae, and the model with a dominant dark energy component became the concordance model of cosmology. Dark energy has changed our view of the role of dark matter in the universe and our vocabulary for describing the cosmological possibilities. If this paper had been written a decade ago, before any serious consideration of dark energy, the focus would have been on the mass density. According to Einstein’s general theory of relativity, in a universe composed only of matter (particles and radiation), it is the mass density that determines the geometry, the past history and the future evolution of the universe. For example, if the mass density exceeds the critical value, the self-gravity of the matter would cause the current expansion to eventually halt and reverse and, also, space would be positively curved. If the mass density is right at the critical value, space is flat (Euclidean) and the universe expands forever. Hence, the structure and fate of the universe would rest on the value of the ordinary plus dark matter 2density. With the addition of a new component, the story is totally different. First, what determines the geometry of the universe is whether the total energy density equals the critical value, where now we add to the mass contribution (identifying its energy according to E=mc2 2) the dark energy contribution. Second, the period of matter domination has given way to dark energy domination. So, the important cosmological role of dark matter is in the past when it was the dominant contribution to the energy density, roughly the first few billion years. Our future is determined by the nature of the dark energy, which is sufficient to cause the current expansion of the universe to accelerate, and the acceleration will continue unless the dark energy should decay or change its equation of state. Figure 1. The luminous (light-emitting) components of the universe only comprise about 0.4% of the total energy. The remaining components are dark. Of those, roughly 3.6% are identified: cold gas and dust, neutrinos, and black holes. About 23% is dark matter, and the overwhelming majority is some type of gravitationally self-repulsive dark energy. We have neglected one very important sub-plot up to this point – dark matter as the agent producing the growth of cosmic structure. We would not exist today were it not for the dark matter, which played a crucial role in the formation of the present structure in the universe. Without dark matter, the universe would have remained too uniform to form the galaxies, stars and planets. The universe, while nearly homogeneous and isotropic on its largest scales, shows a bewildering variety of structures on smaller scales: stars, galaxies, clusters of galaxies, voids and great walls of galaxies have been found. The only known force capable of moving matter on such large scales is Newton’s gravity. And since, in a smooth and uniform medium, there will be no irregularities to produce gravitational forces, all structures must have been seeded by small fluctuations imprinted on the universe at very early times. These fluctuations should leave a signature on the CBR radiation left over from the big bang. Ordinary matter could not produce fluctuations to create any significant structures without leaving a signal bigger than what was observed in the CBR, because it remains tightly coupled to radiation, preventing it from clustering, until recent epochs. 3) On the other hand, dark matter, which is not coupled to photons, would permit tiny fluctuations (consistent with the CBR observations) to grow for a long, long time before the ordinary matter decoupled from radiation. Then, the ordinary matter would be rapidly drawn to the dense clumps of dark matter and form the observed structure. There would still need to be initial fluctuations, but their amplitude could be substantially smaller than otherwise. In 1991, the COBE satellite team announced the successful detection of these fluctuations, confirming an entirely independent argument for the existence of dark matter. The required material was called Cold Dark Matter (CDM), since, in addition to its properties of invisibility and gravitational self-attraction, it was necessary for it to consist of non-relativistic particles to produce the observed structure and these, for simplicity, were assumed to contain no internal thermal motions, i.e., they were cold. A final important ingredient in the standard paradigm must be mentioned before we can begin to assess the validity of the picture. The initial spectrum of perturbations (ratio of long waves to short waves) must be specified in order to predict the gravitational effects of these waves. The inspired guess proposed independently by physicists Harrison, Peebles and Zeldovich in the 1970’s was that the initial density fluctuations were “scale-invariant.” That is, if we decompose the energy distribution into a sum of sinusoidal waves of varying wavelength, the wave amplitudes of the waves were the same for all wavelengths. One of the great triumphs of the inflationary scenario (17, 18, 19, 20, 21) is that it provided a well-motivated, dynamical mechanism for producing a nearly scale-invariant (defined by “spectral index”: n = 1) spectrum. This prediction has now been confirmed by the WMAP satellite team, which found n = 0.99 +- 0.04 (22). Hence, it seems that our observational data has now confirmed our basic hypotheses and provided detailed information about the amount of dark matter in the universe and the initial distribution of matter and energy. This provides a complete prescription for the conditions that lead to the growth of gravitational perturbations and the development of the universe to the state in which we now see it. It should be a matter of straightforward, if complex, computation to see if the developments predicted by this model agree with the universe as seen around us and also with its earlier phases as seen through the time machine made possible by powerful telescopes peering back into earlier epochs. But we cannot claim to understand the evolution of structure in the universe, if we do not know the nature of the dark matter and how it fits within our models of fundamental physics. But, there is more at stake than that. The mass, stability, and interactions of dark matter with itself and with ordinary matter will all affect how dark matter participates in the formation of structure in the universe. Two kinds of dark matter are already known, neutrinos and black holes, (23) but they are generally thought to be minor contributions. Although there are current favored candidates for the majority component, it is the precise nature of the dark matter that is currently the most uncertain and interesting issue. Here we explore these issues: the possible candidates, their implications for structure formation, and how we might use a combination of particle detectors and astronomical observations to resolve the nature of dark matter. 4) THE FAVORED CANDIDATES FOR DARK MATTER For over a decade, the favored candidates for dark matter have been hypothetical elementary particles that are long-lived, cold and collisionless. Long-lived means the lifetime must be comparable to or greater than the present age of the universe, about 14 billion years. Cold means that the particles are non-relativistic at the onset of the matter-dominated epoch so that they are immediately able to cluster gravitationally. Because clustering occurs on length scales smaller than the Hubble horizon (age of the universe multiplied by the speed of light) and the Hubble horizon was much smaller at matter domination than today, the first objects to form – clumps or halos of dark matter – were much tinier than the Milky Way and much less massive. As the universe expanded and the Hubble horizon grew, many of these first small halos merged to form larger scale structures, which later merged themselves to form yet larger scale structures. The result is a hierarchy of structure ranging over many orders of magnitude in volume and mass, in accordance qualitatively with what is observed. In contrast, hot relativistic particles, such as light, massive neutrinos, would be moving too fast at matter domination to gravitationally cluster, and would result in a dramatically different distribution of structure inconsistent with what is observed. Hence, it has been known for nearly 20 years that light neutrinos must be a negligible component of the dark matter mass density, a conclusion that has been recently supported by measurements of the neutrino mass in underground solar neutrino experiments. Collisionless means that the interaction cross-section between dark matter particles (and between dark matter and ordinary matter) is so small as to be negligible for densities found in dark matter halos. The particles are only gravitationally bound to one another and travel unimpeded in orbits in the halos with a broad spectrum of eccentricities. Cold, collionless dark matter has been favored for several reasons. First, numerical simulations of structure formation with cold, collisionless dark matter agree with most observations of structure. Second, for a special subclass known as WIMPs (weakly interacting massive particles), there is a natural explanation for why they have the requisite abundance. If particles interact through the weak force, then they are in thermal equilibrium in the first trillionths of a second after the big bang, when the density and temperature are high, and, then, they fall out of equilibrium with a concentration that is simply predicted from their annihilation cross-section. For a weak force cross-section, the expected mass density today spans a range that includes 20-30% of the total energy density of the universe, as observed. A third reason for favoring cold, collisionless dark matter is that there are specific appealing candidates for the dark matter particles in models of fundamental physics. One candidate is the neutralino, a particle that arises in models with supersymmetry. Supersymmetry, a fundamental aspect of supergravity and superstring theories, requires a (yet unobserved) boson partner particle for every known fermion and a fermion partner particle for every known boson. If supersymmetry were extant today, the partners would have the same mass. But, because supersymmetry is spontaneously broken at high temperatures in the early universe, today the masses are different. Also, most supersymmetric partners are unstable and have decayed soon after the symmetry breaking. However, there is a lightest partner (with mass of order 100 GeV) that is prevented by its symmetries from decaying. In the simplest models, 5these particles are electrically neutral and weakly interacting – ideal candidates for WIMPs. If the dark matter consists of neutralinos, then large, sensitive underground detectors can detect their passage through the Earth as our planet travels around the Sun and through the dark matter in our own solar neighborhood. There are numerous efforts underway today that are beginning to explore the likely range of mass and cross-section of neutralinos. However, that detection does not necessarily mean that the dark matter consists primarily of WIMPs, which might quite possibly be, like neutrinos, only a small subcomponent of the dark matter. Another appealing candidate is the axion, a very light neutral particle (with mass of order 1 µeV) important in suppressing strong CP violation in unified theories. The axion interacts through such a tiny force that it is never in thermal equilibrium, so the explanation for its abundance is not as simple. It immediately forms a cold Bose condensate that permeates the universe. For the axion, also, detectors have been built and have been running for several years. The facts that cold, collisionless dark matter is simple to parameterize, results in numerical simulations which agree with most observations, and is motivated by particle physics explain why it is the leading candidate. But, the real test is just beginning, as vast improvements in numerical simulation and observations in recent years are leading to much more precise tests. CRACKS IN THE FOUNDATION Because the concordance model, combined with the assumption of cold, collisionless dark matter, is mathematically quite specific (even if some of the parameters that enter into it are known imprecisely), it can be tested at many different physical scales. The largest scales (thousands of megaparsecs (Mpc) – one parsec is 3.26 light-years, a kiloparsec (kpc) is one thousand parsecs and an Mpc is one million parsecs) are seen in the CBR itself. These measure the primordial distribution of energy and matter when their distribution was nearly uniform and there was no structure. Next come measurements of the large-scale structure seen in the distribution of galaxies ranging from several Mpc to nearly one thousand Mpc. Typically, these measurements span concentrations of dark matter ranging from small to intermediate. Over all of these scales, observation and theory are consistent inspiring great confidence in the overall picture. However, on smaller scales, from one Mpc down to the scale of galaxies, kpc, and below, there is confusion. Either the results of the tests are uncertain, or they indicate disagreement with the naïve expectations of the theory. These apparent disagreements began to surface several years ago (24, 25, 26) and no consensus has emerged as to whether or not they represent real problems. For the most part, theorists believe that, if there is a problem, it is much more likely to be due to our specific assumption about the nature of dark matter rather than a problem with the global picture given by the concordance model. That there should be more uncertainty about smaller objects that are relatively closer may seem puzzling at first. First, on large scales gravity is king, so an understanding of the predictions involves only very straightforward computations based on Newton’s and Einstein’s laws of 6gravity. On smaller scales, the complex hydrodynamical interactions of hot, dense matter must be included. Second, the fluctuations on large scales are very small (a few percent or less), and we have very accurate methods of computing such quantities. But, on the scales of galaxies, the physical interactions of ordinary matter and radiation are quite complex. Supercomputer simulations are required, but they are not yet entirely reliable or reproducible from one investigator to another. As the problems have emerged, there have been changes both in the observational domain and the claimed theoretical predictions, further complicating the situation. The principle purported problems found on smaller scales are as follows: 1) Substructure, small halos and galaxies orbiting within larger units, may not be as common as is expected on the basis of numerical simulations of cold collisionless dark matter: a) The number of halos expected varies roughly as the inverse of the mass, so many dwarf systems, similar to our companions, the Magellenic Clouds, should be found – far more than. b) The lensing effect of small halos should be evident from the distribution of brightnesses of multiple images of a given galaxy, but the current evidence is inconclusive. c) The small halos, spiraling into the Milky Way and other systems should puff up the thin discs of normal galaxies by more than is observed. 2) The density profile of dark matter halos should exhibit a “cuspy” core in which the density rises sharply as the distance from the center decreases, in contrast to the central regions of many observed self-gravitating systems: a) Clusters of galaxies, as observed in studies of gravitational lensing, have less cuspy cores than computed models of massive dark matter halos. b) Ordinary spiral galaxies, such as our own, have much less dark matter in their inner parts than expected (31, 32), as do some low surface brightness systems . c) Dwarf galaxies, like our companion systems, Sculptor and Draco have nearly uniform density cores in contrast to the expected cuspy density profile. d) Hydrodynamic simulations produce galaxy disks that are too small and have too little angular momentum compared to observations. e) Many high surface brightness spiral galaxies exhibit rotating bars, which are normally stable only if the core density is lower than predicted. Addressing these issues is complex, and we are still mired in uncertainty. With regard to it seems likely that the explanation for the relatively small number of faint galaxies lies in the physics of galaxy formation. The explanation is that halos having a central potential less than or comparable to the ionization energy of hydrogen will not be able to retain photo-ionized gas, and form stars. Hence, they are effectively invisible and would not be counted by observers. Current strong lensing estimates using the distribution brightness ratios of multiple images of a given galaxy to determine the amounts of small-scale structure orbiting a galaxy, are difficult to understand. On the other hand, seeming evidence for small halos been found; on the other hand, it suggests more small halos than expected. A reasonable 7conclusion is that the observed distribution of brightness ratios may be due to effects other than small halos. Item (1c) is even less easy to pin down; if the discs form late enough and the matter density is small enough, so that most infall occurs early, then the disruption and thickening of late forming galactic disks by infalling satellites is unimportant. In sum, the evidence with respect to amounts of substructure observed vs. expected cannot be used at this time to argue either for or against LCDM with much conviction. The second set of objections, based on the cusp density expected for the inner parts of the cold collisionless dark matter also, is observationally somewhat stronger (2a) – (2e). There are definitely many systems that do not show the steep profiles or the high mass concentrations in the inner core, as noted above. Two notions have been raised for resolving the apparent discrepancies. First, there may be dynamical processes that occur through the interaction between dark matter and the baryonic matter near the core that could reduce the central dark matter concentrations (41, 42). These proposals, while ingenious, seem strained, and the physical mechanisms invoked would also tend to disperse the old and dense bulge or spheroid component in a fashion inconsistent with observations. Alternatively, maybe the theoretical predictions of a cuspy profile are not as certain as had been supposed (43, 44, 45). There may be no discrepancy at least for smaller mass halos because cold, collisionless dark matter does not really lead cuspy inner cores after all for such systems. Better dark matter simulations must be performed before we can be sure about whether (2a)-(2c) are serious problems or not. On the other hand, the large angular momentum of galactic disks and the preponderance of barred galaxies is hard to explain. Overall, however, the evidence to date, taken in its totality, does indicate that there is a discrepancy between the predicted high densities and the observed much lower densities in the inner parts of dark matter halos, ranging from those in giant clusters of galaxies (M ≥ 1015 solar masses) to those in the smallest dwarf systems observed (M ≤ 109 solar masses). ALTERNATIVES TO COLD, COLLISIONLESS DARK MATTER The possible discrepancies between theory and observation have motivated new proposals for the nature of dark matter. Each proposed variation from standard cold, collisionless dark matter (CCDM) has two properties: (1) it can “solve” some or all of the problems described in the previous section, and (2) it leads to additional predictions that would distinguish it from all the other alternatives (see Section V). A non-exhaustive list of examples follows: 1. Strongly Self-Interacting dark matter (SIDM): The dark matter might have a significant self-scattering cross-section σ, comparable to the nucleon-nucleon scattering cross-section (46). Then, in any halo, large or small, where the number of particles per unit area (the surface density) × σ is greater than unity, collisions amongst the dark matter particles leads to a complex evolution of the structure. During the initial phases of this process, which lasts longer than the present age of the universe, the central densities decline in the desired fashion due to the scattering of dark matter particles. Also, scattering strips the halos from small clumps of dark matter orbiting larger structures, making them vulnerable to tidal stripping and reducing their number. 2. Warm dark matter (WDM): Dark matter may be born with a small velocity dispersion (e.g., through decay of another species) (47, 48), which leaves it now with only perhaps 100 m/s velocity but which can have a significant effect on small scale structure. Extrapolating back in time, this velocity increases to a value sufficient to have a significant effect on small-scale structure (since the particles are moving too fast to cluster gravitationally on these scales). There are fewer low mass halos and all halos have a less steep profile in the innermost core. Also, because most of the lowest mass halos are born by the fragmentation of larger structures in this picture, they are found in high density regions and the voids tend to be emptier of small systems than in the standard cold, collisionless dark matter scenario. 3. Repulsive dark matter (RDM): Dark matter may consist of a condensate of massive bosons with a short range repulsive potential (49). The inner parts of dark matter halos would behave like a superfluid and be less cuspy. 4. Fuzzy dark matter (FDM): Dark matter could take the form of ultra-light scalar particles whose Compton wavelength (effective size) is the size of galaxy core (50). Therefore, the dark matter cannot be concentrated on smaller scales, resulting is softer cores and reduce small-scale structure. 5. Self-Annihilating dark matter (SADM): Dark matter particles in dense regions may collide and annihilate, liberating radiation (51). This reduces the density in the central regions of clusters for two reasons: direct removal of particles from the center and re-expansion of the remainder as the cluster adjusts to the reduced central gravity. 6. Decaying dark matter (DDM): If early dense halos decay into relativistic particles and lower mass remnants, then core densities, which form early, are significantly reduced without altering large scale structure (52). 7. Massive Black Holes (BH): If the bulk of the dark matter in galactic halos were in the form of massive black holes with mass of about one million solar masses, then several dynamical mysteries concerning the properties of our galaxy could be better understood (53). In normal galaxies dynamical friction between the massive black holes and the ordinary matter would cause those in the central few kiloparsecs to spiral into the center, depleting those regions of dark matter and providing the ubiquitous central massive black holes seen in normal galaxies. While all of these ingenious suggestions were designed to reduce the central densities of dark matter halos, they achieve this end in different ways, and they should have different observational signatures. This provides ways of classifying the alternatives and devising tests that would enable us to eliminate some of the alternatives and further constrain the remaining ones. DETERMINING THE NATURE OF DARK MATTER At first sight, the conceivable alternatives to cold collisionless dark matter are so numerous that it may seem impossible ever to distinguish among them However, the story turns out to be a happy one in that each alternative produces distinctive modifications on small scales that can be tested through improved astronomical observations and numerical simulations. The local universe – the small objects that orbit galaxies and the galaxy cores – turns out to be a marvelous new laboratory for examining the nature of dark matter. The predictions of the various alternatives are distinctive because their modifications to the cold collisionless picture depend on different physical properties. SIDM, BH or SADM only affect halos when the interaction rate rises above a certain threshold value. The interaction rate depends on the surface density if the cross-section is velocity-independent or, more generally, the product of the cross-section and velocity. In all these cases, the interaction effect is slow because (by design) only a few scatterings take place within the lifetime of the Universe. WDM, RDM, or FDM all proposals that have a built-in characteristic length scale below which dark matter halos are affected. DDM has a characteristic built-in time scale after which dark matter halos are affected on all length scales and for all surface densities. The alternatives also alter the history of structure formation compared to the cold collisionless dark matter picture in different ways. SIDM maintains the same sequence of structure formation but slowly rearranges the distribution of dark matter in dense regions. SADM is similar, except that it removes dark matter altogether from dense regions. Depending on details, RDM and fuzzy FDM may or may not affect the sequence of structure formation, either, but they insure that the smaller scale objects are forced to have a low physical density. DDM removes dark matter on all scales beginning after a characteristic decay time; because a lot of mass is lost through the decays, a higher rate of clustering is required throughout to match the observed galaxy cluster masses and match the other proposals. WDM delays the onset of structure formation until the dark matter cools sufficiently to gravitationally cluster, initially suppressing small scale structure formation but then creating it later by the fragmentation of larger scale structures. Finally, the BH alternative requires that there be significant non-linear structure on one million solar mass scales built-in ab initio, rather than grown from small fluctuations. Because of these differences, the candidates for dark matter each face distinctive constraints and challenges. If the cross-section is too large, self-interaction (or self- annihilation) could lead to the evaporation of the halos of galaxies in clusters, in conflict with observation (32, 54). For WDM, for which structure formation is delayed compared to the standard picture, evidence for early galaxy and star formation provides a strong constraint. If the high electron-scattering optical depth apparently found by WMAP is confirmed,(an indicator of significant star formation at very early epochs), there would not be room for any delay (22, 55). Similarly, SADM could potentially destroy all small halos made at early times before they become sites for new small galaxies. A challenge for DDM is that it seems to require a higher production of massive, dense clusters in the early universe than observed in order to obtain the right mass distribution after decay. There may be new kinds of observations that can distinguish among the candidates for dark matter by taking advantage of their qualitative differences, as we discuss below. To be quantitative in our predictions, detailed numerical simulations of each case are necessary and we would urge that these be done in the near future. We would not be surprised if some of the guesses we are putting forward will turn out to be incorrect when accurate calculations are made. First we consider the epoch at which objects of different mass will form in the different scenarios (Fig 1). To give the same structures today, objects of a given mass will need to form earlier in the DDM, SADM, and BH scenarios as compared to the standard CCDM and SIDM scenarios. The low mass objects will form later in at least some FDM and RDM scenarios, and, in the WDM scenario, they will form later and only by fragmentation of more massive objects. The mass of, and even the existence of low mass galaxies at early times will provide a valuable diagnostic to distinguish the alternatives: the WMAP observations favors models which form structure at early times. History of structure formation: the time of formation for objects of a given mass M (as measured at formation) for structures with increasing mass (dwarf, low surface brightness (LSB), ordinary (L*) galaxies and galaxy clusters) for different models of dark matter. Structure formation begins shortly after the onset of the matter dominated epoch (left hand side). Acronyms are explained in text. Next we look at the demography expected to be seen in the local universe when population studies are made. How many small and how many large dark matter halos show exist is presented in Fig. 2. In the WDM, FDM, and RDM scenarios, small mass objects are underabundant compared to the CCDM, SIDM,and SADM scenarios and in the BH scenario, they are probably overabundant. WDM calculations (48) reveal that objects made by fragmentation are present but at a lower level. The small halos may be difficult to observe directly because they may be unable to retain gas long enough to make observable galaxies. But these small dark halos may be detected through their gravitational effects, such as lensing, puffing up of disks, and other dynamical interactions. Demography: how the number of objects of a given type depends on their mass (as observed today) for different dark matter models. The internal structure of the halos provides another feature to distinguish one model from another. In the CCDM model, low mass halos were made early when the universe was denser than later, and so they are themselves more dense than structures formed later. This is shown in their internal structure. So, Figure 3 reflects the historical conditions shown in Figure 1 but allows one to study nearby objects. This is a critical issue because the inner parts of dark matter halos do seem to be considerably less dense than expected in the standard CCDM model. Here the Black Hole scenario is complex. For isolated dark matter halos, which do not contain baryonic components, the dynamical evolution will be qualitatively similar to that of star clusters. On a time scale proportional to the dynamical (or orbital) time multiplied by the ratio of the system mass to the typical black hole mass the inner profile will first flatten and then collapse via a process called the gravo-thermal instability. For parameters appropriate to galactic dark matter halos, even the first process will only occur for the lowest mass dwarf systems and thus less cuspy cores would be expected in the local dwarf galaxies. In normal galaxies the stronger interaction is between the black holes and the normal stellar component, and this leads, as noted before, to clearing out the black holes from the inner parts of the galaxies with them sinking to the center where they either merge or are ejected. Internal structure: how the density density of the inner one kiloparsec depends on the mass of the system for different dark matter models. Finally, we examine the environments within which different kinds of objects should be found. In the standard model, low mass halos will be distributed relatively more uniformly than the higher mass halos, so that the large voids seen in the distribution of massive galaxies should be populated with halos of low mass and perhaps also with associated low mass galaxies. To date, studies have not found such galaxies, but we do not yet know if this because of an absence of the predicted low mass halos in the voids or simply because the ones that are there have not been able to make galaxies. In the WDM scenario, the low mass halos are typically near the high mass ones as they form by fragmentation of larger structures. For the SIDM, SADM, FDM and RDM scenarios, the abundance of low mass objects will decline in the vicinity of the highest mass ones. In SIDM, it will be because interactions will boil away the cooler low mass halos by direct particle-particle collisions, and, in the other three cases, it is because the low mass halos will have a low internal density and be fragile, hence easily shredded in tidal encounters with their bigger brothers. For the Black Hole scenario, the voids would be heavily populated with small dark matter systems, but these might or might not contain observable stellar systems. Environment: how the number of dwarfs in (1 Mpc) volume depends on the average density within that volume. CONCLUSIONS The idea, that some mysterious “dark matter” dominates over the ordinary chemical elements, first broached by Fritz Zwicky over 65 years ago, is now the common wisdom, confirmed by many different lines of evidence. For most astronomical observations the simplest possible choice seems to give an adequate description: the dark matter is primarily made up of elementary particles which are long-lived, cold and collisionless and has been termed cold dark matter. The most direct way to see if this choice is correct is via earth based laboratory particle detectors and several experiments are underway. But there are a variety of clues telling us that the world may not be as simple as the CCDM model. While the CCDM model is able to correctly predict observations made from the largest cosmological scales down to roughly those of galactic scale and from the early universe to the present epoch, there are many indications that on sub-galactic scales it predicts that there should be more dark matter than is detected gravitationally. Numerical simulations seem to predict that all galaxies should contain cuspy cores, where the density of dark matter rises sharply with decreasing radius, and most observations do not confirm this prediction. We need more accurate simulations and more accurate observations to see if these apparent discrepancies are real. If they are, then there are several interesting suggestions which could account for the less cuspy cores and, more importantly, would lead to predictions of other observables that could be used to test the variant pictures. These include the history of dark halo formation, the demography (mass distribution) of low mass halos, the detailed interior density distribution of galaxy halos and the environments within which different kinds of astronomical objects are found. We have sketched out the kinds of astronomical tests that could be made to narrow the search, but if history teaches us anything it is that the next important clues will come from a surprising direction. For example, it may be that our assumption of a single dominant component is simplistic. Some observation or calculation will be made that will reorient our inquiries and, if it happens as has happened so often in the pst, we will realize that the important evidence has been sitting unnoticed under our noses for Decades.
by Rohit Sharma
