Was Time Created During the Big Bang?
Right now the Einstein description of gravity (general relativity) doesn't make sense when it starts to intersect with the minute particles of quantum mechanics. Gravity is normally extremely weak on the quantum mechanical scale, but it becomes a major factor when matter gets compressed by a black hole... or in the Big Bang at the beginning of the universe. String theory is the best candidate at the moment for a "theory of everything" that includes both gravity and quantum mechanics.
Here's an interesting perspective (from a N.Y. Times article) on what time might become in our eventual "theory of everything."
Quantum mechanics has, at its core, the uncertainty principle, which establishes a limit on how precisely particular features of the microworld can be simultaneously measured. The more precise the measurement of one feature (a particle's position for example), the more wildly uncertain a complementary feature (its velocity) becomes. Quantum uncertainty thus ensures that the finer the examination of the microworld, the more frantically its physical features fluctuate, and the more turbulent it appears to be.
For subatomic particles, these fluctuations are well understood mathematically and have been precisely documented experimentally. But when it comes to time and space, the fluctuations speak to the very limits of these familiar concepts. On extremely short time intervals (about a tenth of a millionth of a trillionth of a trillionth of a trillionth of a second) and distance scales (about a billionth of a trillionth of a trillionth of a centimeter), quantum fluctuations so mangle space and time that the conventional ideas of left/right, backward/forward, up/down, and before/after become meaningless.
Scientists are still struggling to understand these implications, but many agree that just as the percentages in political polls are average, approximate measures that become meaningful only when a large respondent pool is canvassed, so conventional notions of time and space are also average, approximate concepts that become meaningful only when considered over sufficiently large scales. Whereas relativity established the subjectivity of time's passage, quantum mechanics challenges the conceptual primacy of time itself.
Here's the important part:
Today's scientists seeking to combine quantum mechanics with Einstein's theory of gravity (the general theory of relativity) are convinced that we are on the verge of another major upheaval, one that will pinpoint the more elemental concepts from which time and space emerge. Many believe this will involve a radically new formulation of natural law in which scientists will be compelled to trade the space-time matrix within which they have worked for centuries for a more basic "realm" that is itself devoid of time and space.
This is such a perplexing idea that grasping it poses a substantial challenge, even for leading researchers. Broadly speaking, scientists envision that there will be no mention of time and space in the basic equations of the sought-for framework. And yet just as clear, liquid water emerges from particular combinations of an enormous number of H20 molecules time and space as we know them would emerge from particular combinations of some more basic, though still unidentified, entities. Time and space themselves, though, would be rendered secondary, derivative features, that emerge only in suitable conditions (in the aftermath of the Big Bang, for example). As outrageous as it sounds, to many researchers, including me, such a departure of time and space from the ultimate laws of the universe seems inevitable.
(From The Time We Thought We Knew, by Brian Greene, N.Y. Times.)
I think what this means is, our theory of everything may end up describing variables which are actually more fundamental than time, space, gravity, and electromagnetism (the basic forces and dimensions in today's theories). What we experience as "time" may actually have been created during the Big Bang. Time could be a macroscopic manifestation of the more intrinsic components of the universe/multiverse.