Whenever a True Believer™ shows up here at SEB with the intent of convincing me of the error of my lack of faith in the existence of God(s) they invariably end up trying to use my acceptance of scientific explanations for reality against me by resorting to many of the classical Big Questions that science hasn’t been able to answer yet. Questions like: “Where did the Universe come from? Something can’t come from nothing.”
I’m a fan of Occam’s razor so my reply is pretty simple: Einstein’s Special Theory of Relativity has shown us that energy can’t be created or destroyed, but it can change form (E=mc2). Logically then the energy that makes up the Universe must have always existed in one form or another. Being that this explanation removes the need for a God of some sort to snap his fingers and create something from nothing (an irony considering the oft-repeated insistence that something from nothing is impossible) it ends up never being received well by the person who asked the question. Most commonly I get asked the nonsensical follow-up question: “How could the energy have always been there if there was nothing before the Big Bang?” Which just shows how poorly the concepts of “always” and “nothing” are grasped by these people.
However this isn’t to say that my simple explanation isn’t without its own problems under the traditional Big Bang theory as taught in most High Schools. According to the General Theory of Relativity if you rewind time backwards the Universe collapses down into a gravitational singularity where the density of the Universe is such that the curvature of space-time are infinite and the rules of classical physics break down. Certainly it’s possible that a dot of infinitely compressed energy could exist for eternity, but then what would cause it to suddenly explode outward and become the Universe as we know it today? As classical physics is useless in such a situation it’s unclear how a Big Bang could even be possible. This is the Big Bang model most folks remember from High School and unless you went on to take more advanced course in college (or just read a lot of books on the subject like I do) you might not be aware that this model doesn’t take into account quantum effects which could provide some of the answers to this problem. Even then the basic model assumes that there wasn’t “anything” prior to the Big Bang other than the energy itself and that time began with the Big Bang. We don’t really know if it’s possible for there to have been anything pre-Big Bang or for certain that the energy has always existed and there are several alternate theories that eliminate the idea of a Big Bang altogether.
So my simple explanation is logically sound, but it still leaves quite a few tough questions yet to be addressed. As a result anytime there’s news about cosmological research on the topic it always catches my interest and the folks at Scientific American just printed a doozy of an article called The Myth of the Beginning of Time which takes a look at what recent advances in String Theory has to say about the Big Bang and whether or not there was something pre-Big Bang:
String theory suggests that the big bang was not the origin of the universe but simply the outcome of a preexisting state.
One of the assumptions—that relativity theory is always valid—is questionable. Close to the putative singularity, quantum effects must have been important, even dominant. Standard relativity takes no account of such effects, so accepting the inevitability of the singularity amounts to trusting the theory beyond reason. To know what really happened, physicists need to subsume relativity in a quantum theory of gravity. The task has occupied theorists from Einstein onward, but progress was almost zero until the mid-1980s.
Today two approaches stand out. One, going by the name of loop quantum gravity, retains Einstein’s theory essentially intact but changes the procedure for implementing it in quantum mechanics [see “Atoms of Space and Time,” by Lee Smolin; Scientific American, January]. Practitioners of loop quantum gravity have taken great strides and achieved deep insights over the past several years. Still, their approach may not be revolutionary enough to resolve the fundamental problems of quantizing gravity. A similar problem faced particle theorists after Enrico Fermi introduced his effective theory of the weak nuclear force in 1934. All efforts to construct a quantum version of Fermi’s theory failed miserably. What was needed was not a new technique but the deep modifications brought by the electroweak theory of Sheldon L. Glashow, Steven Wein-berg and Abdus Salam in the late 1960s.
The second approach, which I consider more promising, is string theory—a truly revolutionary modification of Einstein’s theory. This article will focus on it, although proponents of loop quantum gravity claim to reach many of the same conclusions.
The full article is broken up over seven pages and hits on some concepts of String Theory that I’m still getting my head around, but the basic gist of it all is that under String Theory it appears that there could have been something other than just an infinitely compressed point of energy pre-Big Bang and time itself may actually be eternal. String Theory at least helps to resolve the paradox that crops up in the case of a gravitational singularity as the theory predicts that strings cannot collapse to an infinitesimal point.
There’s still a lot of work to be done on the theory and the amount of experimental data backing it up is small at this time, but if it holds up as cosmologists continue to investigate it then it may not be too long before we can actually answer the question of “What was there before the Big Bang?”