I was wondering:
About entropy. What I’ve read and not passed out while reading has led me to believe that entropy, the increase of disorder, would lead to an increasingly warm and decreasingly effective universe. By decreasingly effective, I mean that it would be harder to get a yield from any give reaction or process. So, would the universe eventually slow down and stop and wallow in its own heat? Would the matter of the universe seek to release its potential energy by returning to a center point? Would the return to singularity combine with the great heat of the universe allow for a new Big Bang? Could this mean that the Universe doesn’t really have a beginning, but repeats infinitely the explosion-expansion-implosion process? Is my concept of entropy entirely wrong?
The reason I bring this up is becuase I’ve seen two strains of thought: Original Boom v. Divine Creation, and I thought well, why is there necessarily (sp?) a creation? WHy not infinite repetition? What I understand of singularity (the compression of matter into a single point) is that all the laws of physics go out the window and time itself becomes meaningless (vanished? stretched? simply gone? held in abeyance?).
Is all this a possibility? Am I rehashing old thoughts? Am I blowing smoke up my tailpipe?
I’ve seen quite an interesting collection of people on this board and thought I’d toss this all out there.
Well, the oscillating model(expansion, contraction, expansion) is attractive because it takes away the need to explain creation. The Universe cycles endlessly, and we live between one of those cycles.
However, the majority consensus is that the Universe will expand forever and ultimately suffer maximum entropy, where nothing further can happen. This is called the Heat Death and is borne out by observation.
But that opinion may yet change. We simply don’t know enough yet.
There is also the Baby Universes idea that was put forth by Hawking. It’s possible that at the Big Bang tiny bubbles of space formed and inflated to form other Universes. This process may still be continuing in black hole regions today. We may be inhabiting one of those Baby Universes
It’s a very complex question. As far as I know, it has not been solved, and in my opinion, never will be.
How to you step outside the Universe to observe it, when the Universe is everything that there is?
What you are talking about is certainly possible. It all depends on how much matter there is in the universe. According to what we currently know there isn’t nearly enough matter to cause the universe to recollapse into a “big crunch” (IIRC, we are missing about 80% of the necessary matter).
It is also possible that there never was a big bang either and that the universe goes through a yo-yo effect getting very close to a singularity but not quite and then the universe reexpands in the “reverse” direction. The best way to picture this is a pendulum. Imagine the pendulum is the expansion of the universe. It expands in one direction (swings out),then contracts (goes back to the center), then expands BUT in the “other” direction (swings back out). Needless to say the expansion of the universe is more complicated than a mere pendulum so the claim isn’t that the universe would be a mirror image of our universe, in fact, what the “other” direction means is highly debatable.
What more could you expect from somebody who lets people kick him to the head?
A very valid point, Surgoshan. FTR, scientific (as opposed to theological) concepts of the origin of the Universe fall into three categories:
Big Bang, dealt with in your post and elsewhere.
Steady State. Some highly competent cosmologists were holding out for this as little as ten years ago, though I have not read of anybody still advocating it. This is a Universe that has lasted forever and continues forever, with matter being created ex nihilo to fill in the gaps as expansion continues.
Pulsating Universe. This is basically what you advocated, and many reputable cosmologists feel that there may be some accuracy to it. Essentially over a multi-billion-year time frame the universe expands from a Big Bang, comes to rest under the influence of its own gravitation, and then contracts to a Big Crunch, which then undergoes the Big Bang again, repeating the cycle. The whole business of “the missing mass” is attempting to get the mean density and total mass of the universe high enough to allow for this closure and contraction.
One interesting point is that if, as some have hypothecated, space and time are the results of matter and energy, not just the independent vehicle in which they exist, then the cycle would be closed in space and time, with the contraction cycle reversed in time and the instants of the Big Bang and Big Crunch as the limits of time (analogous to Absolute Zero - while one can conceive of “colder than absolute zero” or “time prior to the Big Bang,” the concepts have no meaningful referent in reality.
This is a very brief and skim-my summary of these theories, and somebody like Undead Dude may be able to deal with them in more detail than I can. To the best of my knowledge, it’s accurate, but I welcome corrections and clarifications to it.
For an interesting discussion of ideas concerning the fate of the universe, see The Fate of Life in the Universe, by Lawrence M. Krauss and Glenn D. Starkman, in the current (November 1999) issue of Scientific American.
Basically, if current observations are borne out, and the universe is expanding at an accelerating rate, eventually the observable universe will reduce to our local, gravitationally-bound, galactic cluster. All the other galactic clusters will have moved off so quickly that they can never be reached, even at the speed of light. The authors contemplate the consequences of this rather lonely seeming future on the possibility of some kind of life continuing for as long as thermodynamically possible.
Regarding the origin of the universe, has anyone taken into account that the exterior dimensions of a black hole with a mass equivalent to the universe would be approximately those of the universe? Could the Big Bang have originated in the pinching off of a collapsing star in another universe? (Granted it would have had to be either a ultrahypermassive star or different matter/energy constants would have had to have prevailed there.)
I asked this in a different thread, but it may get missed there.
How come the universe is expanding at an accelerating rate? I can understand that, as things get farther apart, the gravitational attraction between them diminishes, but that would seem, to me, to simply let them continue apart at their current speed…not allow them to speed up.
Is there some subatomic repellent force that also acts on a macro scale?
The accelerating expansion of the universe is what physicists call inflation. In the early universe, space-time itself expanded faster than the speed of light, carrying bits of matter and energy far enough apart to move out of causal contact. That’s one reason the universe could get as lumpy as it is, rather than being a uniform ball of matter.
In my understanding (I am an ex-physicist, but was never a cosmologist), inflation was, until recently, thought to be over rather a long time ago, with the further evolution of space-timee continuing only under the influence of gravity. In that case, the universe could be closed (the Big Crunch idea), open (space continues to expand, but slowing to some non-zero limiting expansion rate at infinite time), or flat (the expansion continues to slow, but approacing zero at infinite time). But recent observations hint that inflation may be continuing, although at a much slower rate than in the early universe. In this case, there is some “pressure” flinging the universe apart at an ever increasing rate. This means that stuff that is very far away will eventually be moving away from us faster than the speed of light, and will therefore be unreachable, even at light speed.
It’s not merely the OBJECTS in the universe that are flying apart. The universe ITSELF is flying apart. SPACE is expanding.
Imagine if you will a great big balloon, with a TWO-dimensional universe on its surface. As the balloon expands, the 2-dimensional objects on its surface get farther apart. (Draw some pictures of some galaxies on a real balloon and then blow it up. You’ll see this happening.)
Now the tough part. EXTEND this image one dimension higher. Imagine our THREE-dimensional universe on the HYPER-surface of a four-dimensional HYPER-balloon. Now blow up the 4-D hyperballoon. The 3-D objects on its surface will get farther apart.
That’s the picture of our universe that some modern Cosmologists have painted. We’re not just in a 3-dimensional space, we’re on the 3-dimensional hypersurface of a 4-dimensional hypersphere. A hypersphere that’s expanding at (and maybe faster than) the speed of light.
Quick-N-Dirty Aviation: Trading altitude for airspeed since 1992.
It’s the cornucopia from hell! How do people think of these things? I saw a scientific american that said the universe could be a 3-D hyperbola or a giant doughnut (torus) and thought “Hey, neat.” How does time expand? How can we be moving faster than light? How can space expand? I thougt it was nothing!
Sigh. I should know better than to ask questions that take 30 years of specific study to fully answer, but I just want to know!
Polycarp said that a black hole with the mass of the universe would be equal in size to the universe.“Could the Big Bang have originated… in another universe?”
I don’t know who originated it, but that theory is at least thirteen years old, because I remember when I read about it (in Florida in 1986).
In fact, I think it was Stephen Hawking who said, “Want to know what it’s like inside a black hole? Look around.”
Raises an interesting possibility, that the black holes in our universe are the homes of other universes, each with their own black holes, each with its own universe, each with their own black holes, on and on and on and on and on…
Those who do not learn from the past are condemned to relive it. Georges Santayana
Surgoshan…and the cornucopia is a Klein’s bottle, to boot!
JAB, we think alike. (Not sure if that’s a compliment, exactly… :)) There was, back in the earliest days of magazine SF, a standard story line exploring somebody from a larger/smaller incorporated universe such as you describe growing/shrinking into ours, or somebody from ours doing likewise into another universe. In most such cases, they were treating atoms as solar systems (nucleus=sun, electrons=planets), a reasonable story assumption given the knowledge of the time.
