This entry follows on my two previous ones:
“Is the Universe Infinite?”
“Dialog on ‘Is the Universe Infinite?’”

I just finished reading a great book, The Endless Universe . It’s by these two highly respected physics guys Paul Steinhardt and Neil Turok .

The Endless Universe argues that the Big Bang / Inflationary cosmological scenario has too many kludges to be plausible anymore. Till reading the book, I hadn’t realized how arbitrary and patched-up the inflationary scenario is by now. Cosmology is really a mess.

Steinhardt and Turok propose a simpler scenario called the cyclic universe or the “ekpyrotic” (Greek for “make of fire”) scenario under which we have two parallel branes (3d hyperplanes, that is, spaces like the universe), and every trillion years the branes spring together and FLASH all of space is filled with energy, and then the branes move apart, but not very far, only about a Planck length apart. Then they stop moving apart and hang there for a trillion years.

While hanging there, the branes expand, producing the galactic recession. The branes are like infinite planes, so they can expand exponentially and always have more room. And then, after a trillion years, they spring back together. The space in between them is sometimes known as “the bulk.” Strictly speaking the branes are 9-dimensional, with 3D for space and the 6 extra dimensions for the curled up and verminous Calabi-Yau-manifold stringy subdimensions. And the bulk dimension in between the branes is the 10th dimension.

There have been, in principle, an infinite number of cycles, that way we don’t need to face explaining the FIRST one. Each tortoise stands on the back of a previous tortoise.

I’d thought the cyclic universe theory had been discredited, but it’s still going strong, and fighting for more air. The old guard of inflation is fighting hard against the cyclic model, not even taking it very seriously. The Endless Universe is somewhat tendentious, arguing hard for the cyclic model over and over. But it convinced me.

Looking on the web, I find there’s a newer Baum-Frampton cyclic model mentioned on Wikipedia . In this model they talk about a cosmic “Big Rip,” which was formulated by some other guys in a paper called “Phantom Energy and Cosmic Doomsday.” The Big Rip is a depressing notion: the idea is that maybe space’s expansion is accelerating so wildly that eventually the expansion overcomes gravity and the nuclear forces so that first Earth is torn to bits, and then our bodies and even our atoms and the elementary particles. No, no, I much prefer the Cyclic Univere. It’s kind of wild these days, how you can find all these far-out science papers online.

One touchy bit in the Steinhardt-Turok model is the odd moment when the branes collide. To my amateur eye, it seems like it might be nicer and more symmetric if the branes passed through each other instead of bouncing. By the way, the branes are, strictly speaking orbifolds, whatever that means…the concept uses some insane juicy buzzwords like “quiver diagrams”.

Some bits from The Endless Universe that impacted my SF sensors:

(1) In seeming violation of the law of conservation of energy, a universe is allowed to “borrow” more energy from the gravitational field with each cycle. Every trillion years, some gravity gets converted into yet more mass and energy—the former mass and energy having been squandered by expansion of the brane space.

(2) Gravity waves are the one thing that might survive from one cycle to the next. But, methinks there may be other vestiges of the previous cycles that are kicked up (down?) into subtler planes; it helps if, as I like to do, we suppose matter to be infinitely divisible. Suppose someone can hear these “voices in the white.”

(3) They mention that if you have a collapse of space that’s not controlled carefully, you get wild asymmetric oscillations where, like, you turn into a million-mile-long cigar or a sheet of paint the size of the solar system: the chaotic mixmaster scenario.

(4) They really dump on the anthropic principle, which one might present as something like this: “A huge number of possible universes exists, and there just happens to be one that has its constants tuned in just the right way to support fleshapoids on a planet orbiting a sun.” I hadn’t realize how desperate and bankrupt the Big Bang/Inflation model had become. Supposedly there are scads of inflating universe and we just happen to be in this pariticular just-right one. It’s much more intellectually satisfying to suppose there’s only one universe and that there are some deep reasons for its properties.

[Note the small profile on the right, my ripple in the Big Flash.]

(5) In either model (inflation or cyclic), it’s been about 14 billion years since the, uh, call it the “Big Flash,” when space was filled with something like white light (higher energy than light, actually). The image of that flash gets in the way of seeing more than 14 billion light years away. But in the cyclic model, the space is in fact endless, and there’s lots of galaxies out past the 14 billion light year haze. I’m supposing (SFictionally speaking) that we can see past the haze via (a) faint gravity waves or (b) subtle energies relating to the as yet unknown subtler levels of matter. Supposedly we have another trillion years to go before the collapse, before the Big Splat that produces the next Big Flash.

(6) During the initial phase right after the Big Flash, a ripple that’s only a few meters across can in fact serve as the seed for a galaxy. Hmm…

[Adult ripple becomes Joey Ramone / T. Rex]

I might write a story about all this: “Voices in the White.”

This entry was posted on Monday, May 5th, 2008 at 9:33 am and is filed under Rudy's Blog. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.