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]

[Quix]

QUTE

Curious--what will you say to the person in the mirror if and when even 15% of such proves to be true?

[Quix]

Thanks for yours.

Was doing it partly for my Dad who also has an interest in such things. I'm curious what might be built by homade tinkerers.

Have read and seen enough in my life to be convinced there's something to at last some of such technologies.

Thanks for your link.

[MacDorcha]

"An object rotating in space (the outer kind) is technically a perpetual-motion machine (an object in motion will remain in motion; an object at rest will remain at rest; until acted upon by an outside force). However, extracting energy from such an arrangement introduces one or more outside forces. "

then why would a universe slow down to crunch again? it IS losing energy if it's slowing down, otherwise, the Universe would only exoand, being "always in motion." planets arent perpetual motion machines anymore than glass is a solid, it's a very slow moving liquid.

[Junior]

The universe is not losing energy. The energy is being converted into a non-useable form (heat).

[MHGinTN]

And according to entropy, that energy is dissipating as the spacetime bubble expands, thus the energy has 'more into which' to spread. Could the action of black holes, as they suck space and time into their warping gravity holes, be responsible for a sort of 'rebounding' effect that is driving accelerated expansion for the field at large?