Question: Hi, I read Brad's answer to the question about the start of the world and stuff. It really interested me but one of the things that caught my attention was that Brad said that some people think the big bang came from nothing. What I want to ask is if the big bang came from nothing then how did it start and where did the nothing come from because nothing could have always existed; everything has to come from something.

That is a good question marieclaire. Firstly, we have no way to test what came before the Big Bang. All of our mathematics and physics only works in this Universe, our Universe, and everything outside of that is not testable (yet).

There have been a few theories that have been proposed to explain the cause of the Big Bang and the origin of our Universe. One is that our Universe is part of many universes, and our Universe was born from a parent universe. This birth would have been the Big Bang. More technically theories suggest a tiny vibrating energy string exploded as the Big Bang.

Things usually come from something, but not always. We can create new particles that did not previously exist in our reference frame. In physics, its always about frames of reference, what we relate to. In our reference frame, beyond the Big Bang was nothing, but something obviously came from it. However, if we start to study that nothing, we might reveal it actually is something, and beyond that something is nothing.

Lawrence Krauss, a physicist, says that nothing is inherently unstable and unsupportable and that eventually it will have to turn into something, via quantum fluctuations creating the Big Bang. The Big Bang is such a complicated thing, it will take a long time to figure out what caused it.