beginning of time

Shrykull · Post by **Shrykull** » 2003-08-08 12:55am

So, as I understand it the theory is that big bang began with the beginning of time, but what made time begin, why isn't all the matter and energy in the universe still sitting in a ball like it was?

Eframepilot · Post by **Eframepilot** » 2003-08-08 01:22am

A leading current theory is that "prior" to the Big Bang, whatever that means in a domain without a time dimension, there was a false vacuum with a very high energy potential. Think of a glass of water saturated with sugar. Randomly, a quantum fluctuation caused the vacuum to transition to a lower energy state. All of the energy was released and KABOOM! space and time began expanding. Or something.

Shiva Archon · Post by **Shiva Archon** » 2003-08-08 02:21am

From what I gathered from Cosmology 101, astronomers can tell you the state of the universe back to 1 second after the Big Bang. Before that...we have little if any factual data. Part of the the problem is that physicists haven't figured out a way to make General Relativity and Quantum Mechanics work together. Maybe when they get those theories straightened out cosmologists can wrap up that first unknown second.

Kuroneko · Post by **Kuroneko** » 2003-08-08 05:32am

Shiva Archon wrote:From what I gathered from Cosmology 101, astronomers can tell you the state of the universe back to 1 second after the Big Bang. Before that...we have little if any factual data. Part of the the problem is that physicists haven't figured out a way to make General Relativity and Quantum Mechanics work together. Maybe when they get those theories straightened out cosmologists can wrap up that first unknown second.

Cosmologists can do better than a second, but in any case there is a fundamental limit dictated by quantum mechanics: Planck time. Below about somewhere in the order of 1E-44 seconds, the known physical laws are no longer meaningful (which is not to say that nothing is going on, only that we don't (and can't) know what).

Relativity, being completely deterministic, doesn't have this problem. But since quantum effects are actually observed, this is a flaw of relativity rather than quantum mechanics.