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Topic: How big is the universe? (Read 2750 times) |
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Bass
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How big is the universe?
« on: 2006-12-19 08:58:03 » |
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I was just wondering how big the universe really was and I thought I would start a new thread on it....I've heard theories about the universe being of infinite mass and theories of boundaries...about the big bang..and the big pinch....(the big pinch is a prediction of the ending of the universe) I saw nobody had put a post about this yet...the closest thread topic was about black holes so chat away about the universe, it's mass, etc.
If anyone has any good links that would be kool too, cause I can't find much.
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Hermit
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Re:How big is the universe?
« Reply #1 on: 2006-12-19 14:32:13 » |
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Matter-energy is a duality which can (generally) neither be created nor be destroyed. Thus, the Universe has a finite energy and mass (that which it possessed at instantiation 13.7 billion years before present (Refer [Church of Virus BBS, General, FAQ, FAQ: Timeline ] ).
Given expansion from a central point at light speed for 13.7 billion years, the Universe is currently at most 27.4 billion lightyears in extent. In reality, it took about 380kY to become transparent to light, so the greatest extents may be almost a billion lightyears smaller. Based on what we understand from gravity, the observation of nova events, and the energy density we are observing, our current consensus opinion is tending towards considering Omega as being less than one, and therefore that our Universe is an open hyperbolic Universe. This being the case, consolidation is unlikely to occur before evaporation.
The matter will eventually all evaporate, leaving an almost evenly distributed energy field which will only cease to exist once the last proton evaporates some 200 billion years from now, leaving the Universe without a reference framework, so ending spacetime (without which our Universe cannot exist).
Regards
Hermit
Try physical cosmoplogy @wikipedia and follow where it leads.
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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Blunderov
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Re:How big is the universe?
« Reply #2 on: 2006-12-19 15:02:28 » |
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[Blunderov] "Space is big - really big - you just won't believe how vastly, hugely mind-bogglingly big it is. You may think it's a long way down the road to the chemist, but that's just peanuts to space."--Douglas Adams
http://www.pbs.org/wgbh/nova/universe/howbig.html
How Big is the Universe?
by Brent Tully
How big is the universe? Could it be infinitely large? If the universe has an edge, what is beyond the edge? And if the universe had a beginning, what was going on before that?
Our experience of the everyday world does not prepare us to grasp the concept of an infinite universe. And yet, trying to imagine that the cosmos actually has a boundary does not make things any easier.
There is an edge to what we are able to see and could ever possibly see in the universe. Light travels at 300,000 kilometers per second. That's top speed in this universe—nothing can go faster—but it's relatively slow compared to the distances to be traveled. The nearest big galaxy to our Milky Way, the Andromeda galaxy, is two million light-years away. The most distant galaxies we can now see are 10 or 12 billion light-years away. We could never see a galaxy that is farther away in light travel time than the universe is old—an estimated 14 billion or so years. Thus, we are surrounded by a "horizon" that we cannot look beyond—a horizon set by the distance that light can travel over the age of the universe.
This horizon describes the visible universe—a region some 28 billion light years in diameter. But what are the horizons of a civilization that inhabits the most distant galaxies we see? And what about galaxies at the limits of their vision? There is every reason to think that the universe extends a long way beyond the part of the universe we can see. In fact, a variety of observations suggest that our visible patch may be a small fraction—maybe an infinitely small fraction—of the whole universe.
This view of the universe fits with the currently popular idea that the universe began with a vast expansion of size. The idea describes a kind of undirected energy present in the vacuum of space, called scalar fields, that somehow got channeled into a process called "inflation." By conservative estimates, the universe expanded so much during this period that something the size of an atom inflated to the size of a galaxy.
If this grand idea is correct, then the universe is larger than we ever could have imagined. But the question remains: Is there a boundary, and if so, what lies in the voids beyond? The answer, according to some cosmologists, is truly mind-boggling. If the universe sprung forth in this manner, then probably inflation has occurred in other places, perhaps an infinite number of places, beyond our horizon and outside of our time. The implication is that there are other universes, perhaps similar to ours or vastly different, each in its own space and begun in its own time.
Inflation implies a vastly expanded concept of what the universe is. But the concept is also helping us to understand the universe we see around us. Take, for example, the recent observation that the universe is not only expanding—a fact astronomers have known for over seven decades—but actually accelerating outward. That discovery is the subject of NOVA's program "Runaway Universe."
While we can never directly "see" the whole of the universe or glimpse its farthest horizons, we can discover how it is behaving—how fast it's growing, whether its growth will one day come to a halt, and what forces have been driving its evolution on the largest of scales. The evidence for the cosmic acceleration—the observations of distant exploding stars called supernovae (see Birth of a Supernova)—provides a window onto these behaviors.
The discovery of cosmic acceleration was made by examining the light of supernovae. We astronomers believe we know the intrinsic brightness of a particular kind of supernovae, called "Type Ia," so we can calculate how far such an object must be from us by its apparent, or measured, brightness. We also know how fast the supernovae—and the galaxies they're in—are rushing away from us by measuring their "redshift." Redshift refers to a color shift in the light of galaxies toward the red end of the spectrum as they race away from us. The faster a galaxy is moving away, the redder its light becomes. (For more on this phenomenon, go to Moving Targets.)
What we are looking for in this combination of redshift and distance is the "growth rate" of the universe going back in time. This growth rate tells us about the gravity of all the matter in the universe—if there is a lot of matter it will slow down the growth rate over time.
Take the case of a universe with so much matter that gravity arrests the expansion and everything finally collapses in on itself. We call that a "closed" universe. In such a universe, the expansion would have once been much faster. To get to the separations between galaxies that we see now would have taken a relatively short time. Granted, the numbers associated with "relatively short" might still seem daunting.
A second possibility might be a universe that is practically empty, often called an "open" universe. Yes, there must be enough stuff in it to permit the existence of observers like us, but suppose the total amount of matter has negligible gravitational influence on the expansion. This universe is just cruising at the same expansion rate now as in the past. Compared with the first possibility, the closed universe, expansions in the past would have to have been slower to get the presently observed separations between galaxies. And it would mean that a distant supernova observed to be rushing away from us at such-and-such a speed (redshift) is farther away in this case, compared to the dense, closed universe case. In the closed universe case, since expansion was faster in the past, one doesn't have to go so far away (back in time) to arrive at a specified redshift.
So does either of these possibilities describe our universe? No! The one that comes closest is the "open" universe. However, the supernovae are too faint—that is, they are so far away that even that model doesn't allow the supernovae to travel as far away as astronomers observe. Our universe, the real one, must have been loitering after its initial inflationary period, but then put its foot to the accelerator recently to produce the present separations of galaxies.
Whatever could produce that acceleration? Certainly there is nothing in our Earthly experience that prepares us for such a possibility. This is where the theory of inflation comes into play. Now about two decades old, inflation entertains the idea that there is a kind of energy that causes space to expand. This energy competes with gravity, though certainly not on local scales. However, should this form of energy come to dominate, watch out! While gravity tries to crush, this energy—call it vacuum energy, or the scalar field, or the energy represented by the Cosmological Constant in Einstein's equations describing the dynamics of the universe—tries to expand the fabric of space, pushing everything apart. The basic proposition of the inflation model is that this form of energy once dominated gravity and caused our universe to burst forth.
It turns out that the basic inflation picture satisfies a number of observed facts about the universe. One fact is particularly interesting because the better our observations become the more tightly they agree with a prediction of the inflation model. This is that the universe should be "flat"—no overall curvature of space. Spectacularly convincing evidence—recent measurements of irregularities in the microwave background radiation—supports this proposition.
The microwave radiation comes to us from the time in the past when the universe was a primordial fireball. We see a "surface" like we see the "surface" of the sun. We can't look into the sun (or a cloud in the sky) because of scattering of light. As with the sun and its spots, the surface of last scattering of the primordial fireball had structure caused by localized regions that were hotter or cooler, less or more dense. The most pronounced of these structures at the cosmological surface of last scattering were governed by the distance that acoustic (pressure) waves could travel in the age of the universe back then, when the universe was about a half million years old. The size of these irregularities gives us a ruler! The radiation was emitted so long ago, so far away, that it has been redshifted down to millimeter wavelengths. So now millimeter experiments determine the angular size of the clumps caused by acoustic oscillations in the cooling universe at the surface of the last scattering.
We know how big the clumps were—a couple hundred thousand light years across. The relation between their real size, their distance, and the angular size that we observe is governed by the geometry of the universe. A universe dense with matter will distort the final size one way, an empty or almost empty universe will distort another way, and the flat universe of the inflation model will produce yet a different image, which we would intuitively call undistorted. Lo and behold, the results are in agreement with the flat universe of inflation.
This is not the full story. The theory of inflation predicts a precise recipe of how structure would form from little things merging into big things and tells us how many little things there should be for each big thing. The observations match with expectations if the mix of energy and matter is the same as that suggested by the supernovae experiments. Inflation also solves the old controversy over the Hubble Constant, the relationship between the rate galaxies are flying apart and the distances between them. If the Hubble Constant is large then galaxies are relatively close together and the implied age of the universe is way too short if the universe has been briskly expanding. The universe cannot be younger than things in it. However, if the universe has been loitering and is now accelerating, then it is old enough and a large Hubble Constant is still possible. And we can actually make a direct measurement of the mass density of the universe by looking at the motions of galaxies that slosh in the gravitational wells of the matter. We find something that has come to be called "dark matter" there. If the universe is "flat," then this state is achieved through the sum of the mass and energy density. Measurements of gravity perturbations reveal just the needed complement of matter offsetting the repulsive energy indicated by the supernova measurements.
The last couple of years have seen a remarkable convergence of evidence, all suggesting that we live in a universe with a few percent of the normal matter of our everyday experience, maybe 25% of something called "dark matter," which is a name given to hide our ignorance of what it is, and 75% of this energy that wants to push space apart—call it "dark energy." If true, then relatively recently in the history of the universe the "dark energy" has become dominant over "dark matter." During the transient dominance of dark matter, it caused the collapse into all the structure of the universe that we have come to know and appreciate.
Maybe we should be less enamored of dark energy. But it is the delight of physicists because it might provide a laboratory for the moment of creation. It may be that the present source of repulsion is quite different from the primordial situation. Certainly the energy density levels and time scales are vastly different. However, if we can understand the mechanism of the present acceleration perhaps we can get a clue about the acceleration at the first instant of our time.
A complicated scenario indeed! So how big is the universe in the inflation model? It begs the question of what is going on at the boundaries and whether information could be communicated across universes. We suppose not. It may well be that only a tiny part of even our own universe is in our horizon, within the domain that we might hope to know.
Brent Tully, an astronomer at the University of Hawaii, works on problems having to do with the formation of structure and distribution of dark matter in the universe. The discovery of a tight correlation between the rotation rates and absolute luminosities of galaxies became known as the "Tully-Fisher" relation and provides one of the best ways of measuring the size and age of the universe. Tully was Science Advisor and Co-Producer of the NOVA film "Runaway Universe."
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Bass
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Re:How big is the universe?
« Reply #3 on: 2006-12-19 19:26:58 » |
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Ah thank-you both Hermit and Blunderov for that wonderful infomation. I love it when you can satisfy and indulge your curiosity.
Quote from: Hermit on 2003-07-04 14:58:14 | BB (Big Bang): The Quantum Gravity Barrier when Gravity separates from other forces. Beginning of space and time. T=1019 GeV. |
I find the BB very interesting, but the real question I feel is what was before the BB? What may have caused the "Big Bang". (if causation even existed at that point in existence). Could there had been something that was always omnipresent that caused the big bang? Might that precence be deemed a God type thing? Microwaves?
The latter part of that probably applies to what you have already told me in the Atheistic faith? thread on "God", but I was just curious if science also had any knowledge in this aspect of it to, since both seem like to be in two different situations of physics.
I don't know if the BB event could have been caused via intentional purposes or not. I personally always find believers using the BB as evidence for a god saying "it had to have a cause" and somehow think that this is undeniable proof that the universe was created. I think also that this idea of creation is the core meme to some, if not most, believers faith in god (aside from the bible and jesus of course).
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Walter Watts
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Re:How big is the universe?
« Reply #4 on: 2006-12-19 20:27:55 » |
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[Bass inquires:]
"I find the BB very interesting, but the real question I feel is what was before the BB? What may have caused the "Big Bang". (if causation even existed at that point in existence). Could there had been something that was always omnipresent that caused the big bang? Might that precence be deemed a God type thing? Microwaves?"
<snip>
WW points Bass to a dusty ol' thread he started in April 2004.
http://www.churchofvirus.org/bbs/index.php?board=61;action=display;threadid=30160
Certainly not definitive, but sometimes the best way to answer a question is with another question.
Walter
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Walter Watts
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No one gets to see the Wizard! Not nobody! Not no how!
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Hermit
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Re:How big is the universe?
« Reply #5 on: 2006-12-20 01:29:44 » |
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[Bass] I find the BB very interesting, but the real question I feel is what was before the BB? What may have caused the "Big Bang". (if causation even existed at that point in existence). Could there had been something that was always omnipresent that caused the big bang? Might that precence be deemed a God type thing? Microwaves?
[Hermit] Spacetime instantiated after the big bang. Asking temporal questions in the absence of spacetime is meaningless. Without a reference frame, questions about time and space, including questions about causation and existence are meaningless. There wasn't a before. It would be like sitting in deep space and asking, "which direction is up."
[Hermit] What is certain is that nothing baryonic could have existed prior to the end of Planck time, and that includes electromagnetic radiation. This means that even if "something" existed before Planck time, it is not able to interact with our Universe. Which is in my opinion a damned good thing, because if there were and it could and it did, I suspect that we would be no more (reality failure, retry, ignore, abort).
[Hermit] Similarly, in the absence of matter, which establishes gravity and thus instantiates spacetime, questions of time and space (and thus Baryonic existence) become meaningless.
Regards
Hermit
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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David Lucifer
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Enlighten me.
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Re:How big is the universe?
« Reply #6 on: 2006-12-21 11:58:07 » |
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[Hermit] Spacetime instantiated after the big bang. Asking temporal questions in the absence of spacetime is meaningless. Without a reference frame, questions about time and space, including questions about causation and existence are meaningless. There wasn't a before. It would be like sitting in deep space and asking, "which direction is up."
[Lucifer] In A Brief History of Time, Stephen Hawking compared the question "What happened before the big bang?" to "What is north of the north pole?".
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David Lucifer
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Enlighten me.
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Re:How big is the universe?
« Reply #7 on: 2006-12-21 12:00:44 » |
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The universe is 156 billion light years in diameter.
from The Hubble Deep Field: The Most Important Image Ever Taken...
Quote:An astute viewer (such as yourself) may have asked, "How can the universe be 78 billion light years across when the age of the universe is only about 13 billion years?"
Good question, how can something be larger than then distance travelled at the speed of light? Since light from the beginning of the universe has only had 13 billion years to travel (not 78 billion), then shouldn't the universe be only 13 billion light years across? That's a pretty intuitive thought.
But it doesn't take into account that the entire universe itself is also expanding. When a photon of light leaves it's point of origin, it does so at the speed of light, so in a universe that doesn't expand, a photon travelling for 13 billion years traverses 13 billion light years.
In a universe that DOES expand, all of the distance covered by the photon gets increased by a scale factor equal to the rate of expansion of the universe.
Since the universe has expanded some since it left 13 billion years ago, we have the apply a scale factor to account for the expansion. Keeping in mind that the universe is expanding continually, it's not stopping and starting, you have to do some calculus to solve the problem. When you do that, you come up with the size of the universe being 78 billion light years in radius, 156 billion in diameter.
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Hermit
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Re:How big is the universe?
« Reply #8 on: 2006-12-21 13:22:36 » |
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Thanks for the correction, Lucifer. Silly of me not to have remembered to account for the possibly inconsistent Hubble constant - a clear lesson in what happens when we assume that answers are sufficiently intuitive not to bother checking, and also a primary reason why peer (or even smart and sensible layman) review is always a good idea! It is also why, when there are enough smart and sensible people involved (as in the CoV) the quality of answers tends to be remarkably good.
The links off Lucifer's post are fascinating and very highly recommended.
I did notice in the space.com article, that they took 90% of 13.7 Gy as the basis for their estimate, based on first transparency, with the caveat that there is the possibility that the Universe is potentially larger yet. I suspect that this is indeed the case, as the 380 ky number I previously cited represents current thinking.
Kind Regards
Hermit
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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Bass
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Re:How big is the universe?
« Reply #9 on: 2006-12-21 14:39:20 » |
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I'm not quite sure but I think that light is turning out to be somewhat unrealiable. There have been studies done on the speed of light, it is currently in question is the speed of light is slowing down (Which no longer makes it a constant).
This means that the Speed of Light is not the maximum acheivable speed as once believed. I do not doubt by the end of this century that we will either be obliterated or will have some kind of advanced space program.
It is perplexing how the universe can start itself; nothing since then has ever started by itself. This is the only fundemental reason why I think there is some external non-universal force.
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Blunderov
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Re:How big is the universe?
« Reply #10 on: 2006-12-21 16:11:49 » |
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[Blunderov] I have a big problem with something coming from nothing, so any theory that avoids this problem gets my attention. Maybe this is outdated now but the problem remains; what were the precursor conditions to the BB? I find it hard to accept the idea that there were none at all.
http://www.popularmechanics.com/science/air_space/1282511.html
Whither The Big Bang?
Published in the February, 1999 issue.
Astronomy's most fundamental idea, the notion that everything in the universe--including time itself--originated in a spontaneous "big bang" that occurred 10 billion to 20 billion years ago, is being quietly challenged by a simpler theory of creation. This new grand universe (GU) concept claims that the observational data long considered to be proof of the fiery birth of the universe is actually unambiguous evidence of a past collision between already existing formations of matter and antimatter.
"Everything concerning a fireball beginning is wrong and leads the standard cosmological model to deadlock," says Anatoli A. Vankov, the Russian mathematical physicist who developed the GU concept. He spoke with POPULAR MECHANICS during a visit to the United States.
Vankov has detailed his GU concept in the draft of a scientific paper titled "Baryon asymmetry of the observed universe as a clue to resolution of dark matter, galaxy formation and other standard model problems." Behind this imposing title is a radical new view of both the universe and its creation. The baryons to which he refers make up a class of subatomic particles--including protons and neutrons--that combine to form the ordinary matter that makes up our world. Asymmetry, in this case, refers to the apparent absence of matter's theoretically predicted counterpart--antimatter. Now comes the controversial part. "The only way to save baryon symmetry is to suggest that the observed universe is not the whole unique universe," Vankov says. "Our observed universe is a huge matter-made fluctuation that is representative of a multitude of typical universes evenly made of matter or antimatter and chaotically dispersed in infinite flat 3D space."
As radical as Vankov's multiple universe concept may seem, it is attracting attention from leading Western scientists. Among these is Princeton University's James E. Peebles, who with his colleague Robert Dicke predicted that the distant glow of the big bang would appear as ubiquitous cosmic microwave radiation. Vankov, who is now a visiting professor at Southwest Missouri State University in Springfield, credits Peebles with helping him make contacts among Western scientists. It also helps that Vankov has impressive credentials of his own. During the Cold War he spent 35 years working in experimental and theoretical nuclear physics at the Institute of Physics and Power Engineering and the Joint Nuclear Research Institution in Russia.
The Big Bang
Vankov's GU concept appears at a time when the standard cosmological model, which begins with a fiery big bang event, is becoming increasingly more difficult to square with the ultraprecise data streaming to Earth from space-based observatories. The big bang theory is based on optical and microwave observations. The optical studies occurred early in the century. Astronomers found that the colors of distant stars were a bit more reddish than expected. One explanation was the so-called "Doppler effect." It explains that the apparent frequency of radiation emitted by a moving body decreases as the source recedes from the receiver. Building on these observations, Edwin Hubble calculated that the universe is expanding uniformly, and that objects at greater distances are receding at higher velocities.
Tracing this movement backward in time suggested there should have been a moment when the universe was infinitely compressed. Something--the big bang--set it into motion. Bits of matter clumped together, creating galaxies and later stars and planets.
The evidence of that event would be found in 1965. Arno A. Penzias and Robert W. Wilson, working at what was then Bell Telephone Laboratories, discovered that the Earth was bathed in a uniform glow of radiation, at the precise microwave frequency one would expect from a "hot" big bang start.
Theorists remain divided as to whether the expansion that allegedly began with the fiery big bang--and which today can be seen in the "red shifting" of light from receding galaxies and the cosmic background radiation from still deeper in space--will continue. One school of thought says it will. A second predicts gravitational forces will cause the universe to collapse back to its point of origin in a "big crunch." Notwithstanding this uncertainty, Western scientists consider the big bang theory one of the greatest intellectual achievements of the 20th century.
Alternative Cosmology
It wasn't entirely a surprise. Years before Hubble's observations suggested an expanding universe, the Russian mathematical physicist Alexander Friedmann predicted this motion using Albert Einstein's general relativity theory.
As modern space-borne instruments, such as NASA's Cosmic Background Explorer mission, provided more data from distant points in the universe, problems began to creep into the standard cosmological model. "There are many inherent contradictions in the treatment of observational data, cosmic background radiation in particular as well as many unresolved physical problems," says Vankov. "For example, there is no explanation of high-energy cosmic rays." There is also the question of the identity of the so-called "dark" or unseen matter that is believed to account for as much as 90 percent of the mass of the universe.
What the space-based platforms haven't found is also significant. "Baryon asymmetry [the lack of antimatter] is hardly acceptable," says Vankov. "Little room is left to resolve these problems by further refining the standard cosmological model."
The GU concept that Vankov suggests as a replacement for the current cosmological model envisions an infinite, flat 3D "grand universe space" that is filled with limited-volume "typical universes" that are chaotically and uniformly dispersed. Some--like our "home universe"--are made of baryon matter.
To preserve baryon symmetry, other typical universes elsewhere in the grand universe are made of antimatter. No one doubts that antimatter exists. Small quantities have been made in the laboratory. NASA is experimenting with an antimatter rocket engine for 21st century spacecraft. There is no mystery why we don't find antimatter in nature. When matter and antimatter meet, they annihilate each other in a burst of energy and subatomic particles.
Vankov conjectures just this sort of a collision took place billions of years ago when a wandering cloud of antimatter somehow bumped into our home universe. "They are all evolving and disintegrating to give birth to the next generation of universes," Vankov says. He says it is the disintegration of the matter and antimatter that we observe as an expanding home universe.
Hard Fight Ahead
To convince the mainstream scientific community to abandon the big bang theory Vankov will need to do more than offer an explanation that addresses the apparent shortcomings of the standard cosmological model. Vankov tells PM that the editor of one physics journal rejected a paper on the GU concept because he considered it too radical and sweeping a notion.
Vankov acknowledges that important details need to be resolved. His next step is to develop a theory of matter-antimatter mixing so he can conduct a computer simulation of galaxy formation. "I want to explain the idea step by step in the detail needed to convince the physics community that it is right," he says. "It is a great challenge with great consequences."
If Vankov succeeds, the GU concept could replace the big bang as the explanation of how it all began.
[Blunderov]Tangental but very, very interesting is :
Information in a Holographic Universe
(Ping Hermit re Hawking Radiation)
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Hermit
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Re:How big is the universe?
« Reply #11 on: 2006-12-21 20:33:14 » |
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[Bass] I'm not quite sure but I think that light is turning out to be somewhat unrealiable. There have been studies done on the speed of light, it is currently in question is the speed of light is slowing down (Which no longer makes it a constant).
[Hermit] The speed of light is not a constant. Considering it as such involves a massive and invalid simplification of a much more complex reality. The speed of light depends on many, many factors (media, gravity, relative motion, etc.).
[Bass] This means that the Speed of Light is not the maximum acheivable speed as once believed.
[Hermit] It is not a matter of belief. The formula are perfectly satisfactory and the speed of light remains an absolute limit when correctly applied.
[Bass] I do not doubt by the end of this century that we will either be obliterated or will have some kind of advanced space program.
[Hermit] I don't necessarily disagree with you, although there are other alternatives, most of them brutish and nasty, but I do wonder what relationship this thought had to the rest of this?
[Bass] It is perplexing how the universe can start itself; nothing since then has ever started by itself.
[Hermit] Every time a particle instantiates (and is matched by one evaporating) exactly the same(uncaused) event as we hypothesize triggered the instantiation of the Universe happens. It is just that the particles we are familiar with come into being in an expanded Universe with space time and rules of its own, and so are subject to the rules amongst which they are instantiated rather than some others.
[Bass] This is the only fundemental reason why I think there is some external non-universal force.
[Hermit] I suggest you dump it. There is no need I am aware of for such a strange idea, and many reasons why it should not be so.
Kind Regards
Hermit
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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Hermit
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Re:How big is the universe?
« Reply #12 on: 2006-12-21 20:37:13 » |
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Dear Blunderov,
Try to wrap your mind around the previously mentioned wikipedia articles. Ask questions. You may also find reading an introduction to vacuum helpful.
Kind Regards
Hermit
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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Hermit
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Re:How big is the universe?
« Reply #13 on: 2006-12-21 20:46:32 » |
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[Hermit 5] Spacetime instantiated after the big bang. Asking temporal questions in the absence of spacetime is meaningless. Without a reference frame, questions about time and space, including questions about causation and existence are meaningless. There wasn't a before. It would be like sitting in deep space and asking, "which direction is up."
[Lucifer 6] In A Brief History of Time, Stephen Hawking compared the question "What happened before the big bang?" to "What is north of the north pole?".
[Hermit] Exactly what I was trying to convey through my simile; although mine, not suffering from hypothetical virtual extensions (which might allow for "What is South of the North Pole?" "The Physical North Pole." and other such relativistic Platonic tomfoolery) might be better in this instance. Nevertheless, thank-you again.
Kind Regards
Hermit
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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David Lucifer
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Enlighten me.
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Re:How big is the universe?
« Reply #14 on: 2006-12-23 01:44:33 » |
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[Bass] This is the only fundemental reason why I think there is some external non-universal force.
[Hermit] I suggest you dump it. There is no need I am aware of for such a strange idea, and many reasons why it should not be so.
[Lucifer] I agree with Hermit. The hypothetical external non-universal force doesn't help. What started it?
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