The Case for a Creator - Lee Strobel [60]
“Another problem is that in order for the universe to oscillate, it has to contract at some point. For this to happen, the universe would have to be dense enough to generate sufficient gravity that would eventually slow its expansion to a halt and then, with increasing rapidity, contract it into a big crunch. But estimates have consistently indicated that the universe is far below the density needed to contract, even when you include not only its luminous matter, but also all of the invisible dark matter as well.
“Recent tests, run by five different laboratories in 1998, calculated a ninety-five-percent certainty that the universe will not contract, but that it will expand forever. In fact, in a completely unexpected development, the studies indicated that the expansion is not decelerating, but it’s actually accelerating. This really puts the nails in the coffin for the Oscillating Model.
“And one more problem: even if physics allowed the universe to contract, scientific studies have shown that entropy would be conserved from one cycle to the next. This would have the effect of each expansion getting bigger and bigger and bigger. Now, trace that backwards in time and what do you get? They get smaller and smaller and smaller, until you finally come to the smallest cycle—and then the beginning of the universe. So Joseph Silk, in his book The Big Bang, estimates that even if the universe were oscillating, it could not have gone through more than a hundred previous oscillations prior to today.” 37
All of this did, indeed, seem to doom this theory. “Sagan was an agnostic who liked to say that the universe ‘is all there is, or ever was, or ever will be,’ ” 38 I said. “But you’re saying that the evidence indicates—”
“—that the Oscillating Model itself implies the beginning of the universe which its proponents sought to avoid. That’s right,” Craig said.
“But,” I pointed out, “permutations of his theory are being proposed even today.” I removed a newspaper article from my briefcase and read the headline to Craig: Princeton Physicist Offers Theory of Cyclic Universe. 39
“This cosmologist says the Big Bang is not the beginning of time but a bridge to a pre-existing era,” I said. “He says the universe undergoes an endless sequence of cycles in which it contracts with a big crunch and reemerges in an expanding Big Bang, with trillions of years of evolution in between. He says mysterious ‘dark energy’ first pushes the universe apart at an accelerating rate, but then it changes its character and causes it to contract and then rebound in cycle after cycle.”
Craig was familiar with the concept. “This model is based on a certain version of string theory, which is an alternative to the standard quark model of particle physics,” he explained.
“The scenario postulates that our universe is a three-dimensional membrane in a five-dimensional space, and that there’s another three-dimensional membrane which is in an eternal cycle of approaching our membrane and colliding with it. When this happens, it supposedly causes an expansion of our universe from the point of collision. Then our universe retreats and repeats the cycle again, and on and on.
“The idea is that this five-dimensional universe is eternal and beginningless. So you have a cyclic model of our universe that is expanding, but nevertheless this larger dimensional universe as a whole is eternal.”
Though difficult to conceptualize, this idea had a certain amount of appeal. “What do you think of this model?” I asked.
“Well, this isn’t even a model, it’s just sort of a scenario, because it hasn’t been developed. The equations for string theory haven’t even