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Cyclic Universe a Possibility
An Anonymous Coward writes "Spacedaily has a post(from Science) about a new theory at odds with the big bang theory. The researchers claim that this theory of an oscillating energy field could be experimentally tested in the coming years."
On April 25, All Things Considered on NPR did a five-minute story on this new Science article. Highly recommended, gives some good background not only on how this theory fits better with some of the current data that we are collecting, but also talks about how difficult it is for a new theory to gain acceptance in the scientific community when it flies in the face of a long-established theory.
modern choral music...
This one might piss off the religious right. The Big Bang could sort of be reconciled with the idea that God created the world in 7 days, since maybe the Big Bang happened on the first day. But the idea that the universe has always existed (and therefore predates creation) is a big problem, since it excludes God from the picture.
I'll be interested to hear the religious responses to this theory.
The Cyclic Universe: An Informal Introduction
Authors: Paul J. Steinhardt, Neil Turok
The Cyclic Model is a radical, new cosmological scenario which proposes that the Universe undergoes an endless sequence of epochs which begin with a `big bang' and end in a `big crunch.' When the Universe bounces from contraction to re-expansion, the temperature and density remain finite. The model does not include a period of rapid inflation, yet it reproduces all of the successful predictions of standard big bang and inflationary cosmology. We point out numerous novel elements that have not been used previously which may open the door to further alternative cosmologies. Although the model is motivated by M-theory, branes and extra-dimensions, here we show that the scenario can be described almost entirely in terms of conventional 4d field theory and 4d cosmology.
In spite of the "informal" claim, the paper is fairly dense - IAAPA (I am a professional astronomer) and I found it heavy going. But the link above has PDF versions if you're interested.
"I will take the Ring," he said, "though I do not know the way."
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I sig, therefore I was.
The latest versions of the big bang theory, with the addition of dark energy or whatever, of an extra repulsive force, predict, basically, the entropic death of everything - the universe as we know it today, with hot stars and habitable planets and the like, exists for some finite period and then disperses forever.
There is certainly a desire - I feel it, myself - that the universe not be that way. It is far more pleasant to think that it will regenerate itself and that complex phenomena like life could re-emerge in some subsequent cycle. However, it is important, as scientists, that we not give in to wishful thinking of that sort.
While these branes are a cute idea in a number of respects - not just because a parallel plane full of dark matter is 100% cool old school science fiction - it strikes me that they answer "how can we match our observations to what we want to be true?" rather than "how can we match our explanations to what we observe?"
Which is not to say that it isn't an excellent theory - merely that there is extreme intellectual danger associated this sort of speculation.
Let me say also - Entropy is a thorough bitch. Whatever the laws of physics turn out to be, and whatever cycles they may allow, if subsequent phenomena depend in any way on previous phenomena (phenomena being the most general term I can manage), there will be a tendency for the whole shebang to degenerate, to move into a more likely state. It is possible that the most likely state for the whole universe involves repeated regeneration of galaxy-rich explosions like the one we all inhabit, but it is also possible that subsequent big bangs would be smaller and smaller in size, eventually dwindling below some critical threshold to generate stars and the like.
The good and new comes from no quarter where it is looked for, and is always something different from what is expected.
Sky and Telescope also covered this story, but didn't obscure it with piss-poor scientific writing like this other source did.
As an aside, the other source over simplifies things, and leaves you with the feeling that you learned nothing but marketing hype. It's target is obviously non-astronomers (or we would have read the original paper in an original journal.) Because of that, they should have explained "branes" (and other terms) with more than sound-bytes from involved physicists. Think diagrams, break-out boxes, etc.
It all goes downhill from first post
"The Last Question" by Isaac Asimov.
The story begins in the year 2061, when a colossal computer has solved the earth's energy problems by designing a massive solar satellite in space that can beam the sun's energy back to earth. The AC (analog computer) is so large and advanced that its technicians have only the vaguest idea of how it operates. On a $5 bet, two drunken technicians ask the computer whether the sun's eventual death can be avoided or, for that matter, whether the universe must inevitably die. After quietly mulling over this question, the AC (analog computer) responds: "Insufficient data for a meaningful answer."
Centuries into the future, the AC has solved the problem of hyperspace travel, and humans begin colonizing thousands of star systems. The AC is so large that it occupies several hundred square miles on each planet and so complex that it maintains and services itself. A young family is rocketing through hyperspace, unerringly guided by the AC, in search of a new star system to colonize. When the father casually mentions that the stars must eventually die, the children become hysterical. "Don't let the stars die," plead the children. To calm the children, he asks the AC if entropy can be reversed. "See," reassures the father, reading the AC's response, the AC can solve everything. He comforts them by saying, "It will take care of everything when the time comes, so don't worry." He never tells the children that the AC actually prints out: "Insufficient data for a meaningful answer."
Thousands of years into the future, the Galaxy itself has been colonized. The AC has solved the problem of immortality and harnesses the energy of the Galaxy, but must find new galaxies for colonization. The AC is so complex that it is long past the point where anyone understands how it works. It continually redesings and improves its own circuits. Two members of the Galactic Council, each hundreds of years old, debate the urgent question of finding new galactic energy sources, and wonder if the universe itself is running down. Can entropy be reversed? they ask. The AC responds: "Insufficient data for a meaningful answer."
Millions of years into the future, humanity has spread across the uncountable galaxies of the universe. The AC has solved the problem of releasing the mind from the body, and human minds are free to explore the vastness of millions of galaxies, with their bodies safely stored on some long forgotten planet. Two minds accidentally meet each other in outer space, and casually wonder where among the uncountable galaxies humans originated. The AC, which is now so large that most of it has to be housed in hyperspace, responds by instantly transporting them to an obscure galaxy. They are disappointed. The galaxy is so ordinary, like millions of other galaxies, and the original star has long since died. The two minds become anxious because billions of stars in the heavens are slowly meeting the same fate. The two minds ask, can the death of the universe itself be avoided? From hyperspace, the AC responds: "Insufficient data for a meaningful answer."
Billions of years into the future, humanity consists of a trillion, trillion, trillion immortal bodies, each cared for by automatons. Humanity's collective mind, which is free to roam anywhere in the universe at will, eventually fuses into a single mind, which in turn fuses with the AC itself. It no longer makes sense to ask what the AC is made of or where in hyperspace it really is. "The universe is dying," thinks Man, collecitvely. One by one, as the stars and galaxies cease to generate energy, temperatures throughout the universe approach absolute zero. Man desperately asks if the cold and darkness slowly engulfing the galaxies mean its eventual death. From hyperspace, the AC answers: "Insufficient data for a meaningful answer."
When Man asks the AC to collect the necessary data, it responds: "I will do so. I have been doing so for a hundred billion years. My predecessors have been asked this question many times. All the data I have remains insufficient."
A timeless interval passes, and the universe has finally reached its ultimate death. From hyperspace, the AC spends an eternity collecting data and contemplating the final question. At last, the AC disovers the solution, even though there is no longer anyone to give the answer. The AC carefully formulates a program, and then begins the process of reversing Chaos. It collects cold, interstellar gas, brings together the dead stars, until a gigantic ball is created.
Then, when its labors are done, from hyperspace the AC thunders: "Let their be light!" and there was light.
"she says i'm lousy conversation. as if that's supposed to help."
Okay, a lot of people have been saying that an infinite cycle of exands and contracts would NOT generate infinite heat. Here's what Steven Weinberg has to say:
"Some cosmologists are philosophically attracted to the oscillating model, especially because, like the steady-state model, it nicely avoids the problem of Genesis. It does, however, face one severe theoretical difficulty. In each cycle the ratio of photons to nuclear particles (entropy per nuclear particle) is slightly increased by a kind of friction (known as "bulk viscosity") as the universe expands and contracts. As far as we know, the universe would then start each new cycle with a new, slightly larger ratio of photons to nuclear particles. Right now this ratio is large, but not infinite, so it is hard to see how the universe could have previously experienced an infinite number of cycles."
Pysicist Sidney A. Bludman says:
"Our Universe cannot bounce in the future. Closed Friedman universes were once called oscillatory universes. We now appreciate that, because of the huge entropy genereated in our Universe, far from oscillating, a closed universe can only go through one cycle of expansion and contraction. Whether closed or open, reversing or monotonically expanding, the severely irreversible phase transitions give the Universe a definite beginning, middle and end."
If any of you have counter-quotations from equally famous physicists, I would love to read them. This is all I have found on the matter so far.
It's all going according to
Is this really new? I don't know where I first heard it, but I know that a "big crunch" has certainly been theorized. I've always thought that it seems likely that a big crunch might cause a big bang to follow. I don't know, maybe I was assuming something.
Be that as it may, one perhaps unusual bit of evidence I've always thought in favor of a cyclic universe is the existence of intelligence life on Earth. First of all, I'm pretty much of the belief that intelligent life is hugely, extremely, unbelievably unlikely. I have a feeling that if we inventoried the universe, we would find a small proportion of single cell life, some but almost nonexistent multicellular life, and higher life forms totally absent except for us.
If you look at the complexity of human beings, it's just crazy how many things have to go right to get intelligence. I mean, it took 2-3 BILLION years just to get us, and no other animal form is even close to us.
When you combine that with the fact that it only takes 2-3 million years to fill a galaxy once you have intelligent life even at sub-light speeds, that means it's probably never happened before in this galaxy.
So given that intelligence almost never happens, and it took about 1/7th - 1/4th the age of universe for it to happen here, I think that gives evidence that we needed a hell of a lot of universe cycles to get it to happen.
Sometimes it's best to just let stupid people be stupid.
Whoa... think about what this means. This would mean that space is not like a sphere expanding from a point of almost nothing into the fourth dimension, it means that space goes on forever! An infinite number of civilizations, and an infinite number of civilizations that are almost exactly like ours. And how many civilizations in the last cycle tried in vain to survive heat death and the next Big Clang?
What if the sheets "roll" across space together? If this could happen before heat death in our area, we'd all just be wiped out like a rat on a beach caught in a title wave.
(It would also mean this exact post has been posted on a much superior Slashdot, far far away.)
Remember "Bring 'em on"? *sigh
While there's a superficial resemblence, there's a huge difference between the old oscillatory models and this one.
In the old models, the universe collapsed from many billions of light years across (or even larger - we really have no idea of how big the universe is) back to the singularity of the big bang.
In this model, the universes (plural) only have to move a few millimeters. The big bang occurs when the branes separate (we're in one brane, the other universe is in another), and the big crunch occurs when they collapse again. The point of intersection can even travel faster than the speed of light without violating relativity - it's okin to the scan of a lighthouse beam against a wall a very long distance away.
For every complex problem there is an answer that is clear, simple, and wrong. -- H L Mencken
...into the Anthropic Principle.
Also what's this about `an energy field that pervades the Universe then creates new matter and radiation'? What energy field? How does it get recharged? God of the gaps again? Continuous creation? Didn't we just have an article on scientific something-for-nothing scams?
Got time? Spend some of it coding or testing
Please explain why God, who is supposed to be all-knowing, all-wise, and all-good, would communicate the creation story in such a deliberately confusing way?
I have an exercise for you. I realize that I'm not going to change your mind on the global issues raised in your post with a simple post to Slashdot, but I think I can defend this point well. Moreover, it is an interesting psychology point as well, not merely a religious one.
Let us say you wish to describe in writing, in exquisite detail, the internal workings of your computer. By "exquisite detail", I mean not just what it does, but how it does it, at every level from the "computer science" level down to the "quantum physics" level (for the transistors and similar hardware). You've got a lot of ground to cover, but by and large, one dedicated human could hold most of this in their head on a fairly deep level.
Now, let's say you're going to do this two thousand years ago using only Greek. I'll stipulate you a complete understanding of Greek; that's not the point. How will you describe the workings of a laser, the effects of coherent light, and the effect of two mediums in a CD-ROM? And that's just a small part of the CD-ROM drive, a fraction of one percent of the problem you are faced with.
The only solution? You will need to replicate the scientific revolution. You'll need to create news terms, define them, etc., and basically bootstrap from a thoroughly ineffective language into one that is useful to you, quite analagously to the bootstrapping of computer languages from machine language. It's certainly possible, though it's debatable whether one ancient greek would be able to learn this without significant guidance from a real person (i.e., not just from the writing, but with a teacher).
This is an interesting point of psychology, relating to our diffficulty in thinking with concepts we can't express in some language. Math exists to a large degree to give us a language we can discuss and manipulate mathematical concepts in. Understanding this can be valuable any time you are writing about a concept not fully understood by your potential readers, so this is a practical point, too.
Now, you've got one thick bundle of scrolls there, buddy. It would easily fill several rooms solid (just the blueprints to all your computer chips printed out would be quite a lot, and the technology of the time doesn't allow for onion-skin paper!). But it is conceivable that such a resource could exist.
Now, stipulate the existance of the Christian God with me for a moment. He is omnipotent and omniscient; for any precise formulation you care to give about what you want to know about the creation of the universe, he can provide the same sort of resource. (I can't guarentee that there still won't be points where it simply asserts the truth of something; contrariwise, Godel's Theorum would seem to imply that such points are necessary.) Calling it "massive" is probably an understatement. No reasonable estimation of the size of this resource can be given. But I feel confident placing a lower bound on the current lifespan of a human being; you could not absorb this resource to any significant degree in one lifetime. (It is likely that the resource can be made arbitrarily complicated, esp. if this is not the only universe, so merely extending lifespans really doesn't get you anything. There are two basic lifespans on the cosmological scale, finite and infinite.)
But, that's not the real point. The real point is this: What purpose would such a resource serve? It would be a waste of time to transcribe, it would be a waste of time to try and use it, and nobody has time to try, anyhow. So what are you going to do? Observing that God created the universe is an importent point, but futher details are effectively a waste; a person like you will still never be satisfied (because there will always be more details not given as long as you are alive, and forever if the panverse is infinitely complicated, which even many cosmologists currently talk about with those frothing universes of theirs...), others won't care at all. Inasmuch as purpose can be inferred, again regardless of your belief on authorship, it's quite clear that the Bible is not a text on cosmology.
The only thing you can do is be extremely highly metaphorical, and keep only the importent parts, which the stipulated God in His divine wisdom knows which parts they are, and ruthlessly cull the rest. The Bible is already quite long; should a useless cosmological discussion bloat it arbitrarily large for the purpose of failing to satisfy you? My guess would be no.
As for the "confusing" point, I'd submit that given any text, it is for you to bend to the usage and attempt to gain as much understanding of the author's point as possible, not for the author to spend a bunch of time quantifying and qualifying the point to you ad nasuem (and probably still ending up with you rejecting it anyhow). Again, this isn't just for the Bible, it's for all text, up to and including my post, and it goes double for anything written more then 20 or so years ago, and triple or more for anything more then a hundred years old. Given the word palette the author had to choose from, whether you believe the author divine or not, "day" (which of course is not the English word for day, and thus criticizing it on that point commits the additional sin (pun intended) of criticizing a translation) is as good as anything else.