Black Crunch jams Universal cycle [Cosmology]

Nature Magazine ^ | 23 Decemeber 2002 | PHILIP BALL

[PatrickHenry]

Space might end up dark, thick and boring.

The Universe is not as bouncy as some think, say two physicists. If a Big Crunch follows the Big Bang, it may get stuck that way for ever¹.

A fluid of black holes would bung up space. There would be nothing to drive another Big Bang, and nowhere else to go. The Universe would be, you might say, stuffed.

In a bouncing universe, all the matter currently flying apart slows until it reverses and falls towards a Big Crunch. Some physicists think this could ignite another Big Bang, in an unending sequence of expansion and contraction.

An idea called M-theory suggests how the switch from crunch to bang could happen². The details depend on the shape of space: whether it is infinite and flat, or finite and curved like the surface of a balloon or a doughnut.

Thomas Banks of Rutgers University, New Jersey, and Willy Fischler of the University of Texas at Austin have considered a flat, infinite space in which particles get ever closer and ever denser.

In a space with such features, the smallest kinks in density are amplified into black holes, the densest objects in the Universe. So the whole of space-time would congeal into a very lumpy soup - a black crunch.

"We don't really know what this fluid is made out of," Fischler admits. But he and Banks argue that it may reach a pressure at which it cannot become any denser. At this point, the speed of sound equals the speed of light. Deadlock results.

No theory can cope with a Big Crunch. Because of this, says Fischler, the analysis that he and Banks have performed remains speculative. And a doughnut-shaped Universe could meet a quite different fate, he adds.

References:

1. Banks, T. & Fishler, W. Black Crunch. Preprint http://xxx.lanl.gov/abs/hep-th/0212113, (2002). |Article|
2. Khoury, J., Ovrut, B. A., Seiberg, N., Steinhardt, P. J. & Turok, N. From Big Crunch to Big Bang. Preprint http://xxx.lanl.gov/abs/hep-th/0108187, (2002). |Article|
[See the original article for links in the footnotes]

[MacDorcha]

you think several billion planets and stars wouldnt put up resistance?

[MacDorcha]

proportionately, this would have the same effect.

[Scully]

I wish Physicist would show up. My understanding regarding various theories of so-called "Oscillating Universes" is that they're supposed to undergo an entropy increase each time they bounce, so it can't be an eternal cycle. (I have my doubts about that.)

So do I, because like you, I have my doubts that entropy continues to increase with each bounce.

[Sentis]

MacDorcha wrote "ok, try this... if the laws of physics are the Law of the universe, which would be what you guys are trying to prove, then the bang-crunch cycle MUST end. if there is a definite end, there is a definite begining. thus, God."

I see that you don't understand how space time works very well. In the space time we occupy now, the second law of thermodynamic holds true. However this is not the case during a crunch. Laws of physics exist because of the way the universe expanded in the first milliseconds of this iteration of the universe. Those laws break down when the universe crunches itself nd the laws are basically thrown out the door.

Also a second reason you are not correct is that energy/matter isnt destroyed it is transformed there is no net lose of energy in the universe because there is no place for that energy to go that is outside our space time. What this means is the universe is basically a giant perpetual motion machine as long as it does not expand so far that it cannot contract again. That is why the shape of the universe and the amount of energy contained in the universe is such an important question.

[Sentis]

MacDorcha wrote "if something wont allow things traveling as fast as light to excape, how can we speculate how spinning would effect it?"

MATH

[LibWhacker]

But in the case of the ball on a rope, the "lost" energy goes into stirring up air molecules, etc. Where would the "lost" energy of an oscillating universe go?

[MacDorcha]

but, my point is, if the Bang-Crunch is constant, something MUST keep it going. God. if not, something must have made us exist. God. whatever form He takes, science can only prove him, even when they contradict themselves, and find new "evidence" all it does is further this truth: we will never know everything, but everything exists. if everything exists, their must be an X-factor. the X-factor is God.

[MacDorcha]

ok, you measure the speed of light, then measure the amount of energy required to capture it. but wait, you cant. you can only speculate. you CANT measure something that you cant get a direct reading from, only an assumption.

[Scully]

you think several billion planets and stars wouldnt put up resistance?

Of course they do...the gravitational forces between these masses will eventually cause the Universe to cease its expansion and ultimately condense into a singularity...then, BLAMMO! Another cycle is born.

Again though, I must post a disclaimer: I am not a physicist nor even a professional cosmologist, and Physicist may cause me to eat my words...but this is my understanding.

[MacDorcha]

what is the universe expanding into?

[longshadow]

.... puts to rest the new "crashing brane" theory of oscillating universes, proposed by Steinhardt and Turok.

If their oscillating Universe is based on the "Ekpyrotic Model," you are correct. Polarization is predicted by the BB theory (Inflationary variant, I believe); the Ekpyrotic Model apparently says there should be NO polarization of the CMB. Therefore, the recently observed polarization gives further support to the BB model, while casting the Ekpyrotic model into the darkness....

[PatrickHenry]

... like you, I have my doubts that entropy continues to increase with each bounce.

I've read -- this is 2nd hand only -- that back in the 1930s, someone named Tolman showed that entropy increase was inevitable for a continuously oscillating universe. The reason I'm dubious is that I don't know where the "lost" energy/information would go. It's all got to be preserved in a crunch for yet another performance of the cosmic show. Or so it seems to me.

[MacDorcha]

i just said, the resistance is were it loses its energy. when it loses its energy, it must stop.

[VadeRetro]

... drop the ball, allowing it to swing away from you (make sure it doesnt touch the ground) then let it swing back. it will never hit your face. why does it not hit your face? because it loses energy traveling away from you. if the laws of physics are the Law of the universe, which would be what you guys are trying to prove, then the bang-crunch cycle MUST end. if there is a definite end, there is a definite begining. thus, God.

Your example isn't a closed system. It's dissipating energy into the room via air resistance and frictional heating.

An oscillating Big-Bang, Big Crunch universe would be a closed system. It doesn't run down. Nothing ever escapes it.

[Sentis]

LinWacker wrote"But in the case of the ball on a rope, the "lost" energy goes into stirring up air molecules, etc. Where would the "lost" energy of an oscillating universe go?"

It doesnt have anywhere to go it could possibly be the energy that allows the universe to expand. When that initial occillation stops (Energy/matter becomes trapped in black holes, neutron stars etc) the universe would begin to collapse back to a state of singularity.

[Poohbah]

I dunno about Black Crunch jamming anything. A scoop is very tasty and goes down nicely with a scoop of Mint Fudge and a scoop of Strawberry Vanilla.

[LibWhacker]

. . . if the Bang-Crunch is constant, something MUST keep it going . . .

Think of Newton's First Law.

[Scully]

the X-factor is God.

But you are making an assumption that science cannot make. Scientists attempt to explain observed phenomena according to our understanding...and our understanding increases with each new discovery. What you are using as argument is a leap of faith or intuition that philosophy and theology allow.

[PatrickHenry]

If their oscillating Universe is based on the "Ekpyrotic Model," you are correct.

I've read that such is the case.

[longshadow]

in short, a Big Crunch couldnt take place, as it would be pulled away from the center of the universe,

Okay, I'll take the bait.

Where, precisely, do you think the "center" of the Universe is?