Everywhere! The current best theories say the universe is infinite and flat. This has the mind-bending consequence that the big bang happened everywhere in an infinite universe all at once and then the whole lot began to expand (or another way of looking at it is that it all stayed where it was and the "standard unit of length measure" began to shrink). It's easier to think of a closed universe, like the surface of a baloon, which expands from an infinitesimally small size until it is so big that from a spot on its surface it all looks pretty infinite. Actually inflation theory says that the universe is so very very much bigger than we can ever see, that it may actually be like a very very large baloon after all.

The start of the Big Bang start occured when God explodes itself! How and why? Literally speaking ... the definition of God is thus, "the combined power of all the Atmans souls in the Cosmos in their purified state is what we know as God". At the time of Big Bang and also at the time of pralaya as we call it in Hinduism ... the period when the dissolution of the Cosmos occurs ... in both the stages of the Cosmos ... the beginning and also the end of the Cosmos ... the size of God is but half the size of a thumb ... this means that all the Atmans souls in their purified state combine together to form the size of only half a thumb ... this has been the stated in the Bhagavad Gita by Lord Krishna. This is an irrefutable fact ... none can deny the efficacy of this. It is absolute truth. So much power contained in so less a size ... the energy cannot contain itself even for a fraction ... the moment the complete dissolution of the Cosmos occurs ... it again explodes with a Big Bang ... and starts another Cosmos ... a new Cosmos. All Atmans which are initially in the purified state get scattered all over the Cosmos ... this journey continues for millions and billions of years ... comes a stage when the Cosmos ... the cosmic gases cool down to form galaxies and stars and subsequently solar systems and the planets. It is only when earth type of planets gets created which is conducive for an Atman the soul within to manifest ... does life form starts developing. In the real meaning a live Cosmos now the starts to live and breathe. Until the first life form manifests ... it was a dead Cosmos without life. For an Atman soul to manifest ... it needs a body ... the body can be of an insect, a plant, animal and human being. But, the complete cosmic system is governed by the theory of evolution ... it is not that an Atman can manifest the body of a plant in its first manifestation ... it initially starts as an amoeba (single cell formation) subsequently it evolves into a two cell formation ... a Jiva (living being) and then a multi-cell formation. Subsequently as cosmic life progresses it evolutes into a plant. This plant evolves into an animal and the animal finally evolves into a human being. More here- http://www.vijaykumar.com/is_there_a_god.html

That is a great question pastthepasta. I don't know the answer, but it seems to me that the answer is out there. If you believe that the universe is expanding, that means that at an earlier date it was smaller than it is now. If you think of the expansion as ripples from a rock dropped into water, it is obvious that the expansion/ripples extend out from a certain point. That point should be where the big bang BANGED.

Really no one knows its mostly speculation, and such. Just like no one knows where god comes from know one knows how the universe had actually begun.

I dont believe in the big bang theroy as I think its untrue.

Put some dots on a balloon with a marker. Proceed to blow up the balloon. Where did the dots begin to expand from on the surface of the balloon? Everywhere and nowhere. The Big Bang is not an explosion that happened within space, it was the rapid expansion of space itself and all it contains within it. Imagine the balloon deflated and tightly balled up before you blow it up. Think of it in those terms. There is no center of expansion that can be referenced on the balloon, everything is moving away from everything else. Instead of a 2D plane to a 3D surface, think of the universe as a 3D brane on a 4th dimensional "balloon".

There must still be an epicentre to the big bang where the true origin of space/time originate such force must have had a huge effect on that focul point possible effecting time/space gravity and matter. KIf you drop a stone in a pond the energy discepates out from the centre but exam what happens at that focul point. She stone bends matter (the water inwards) and it is only gravity returning water to its natural state that (bouncing back to form) that causes the ripples and they disciplate through the body that the force has been excerted on. In space the ripples would have been different as the body that energy has to travel through would be different. In deed if the the big bang was the origin of all matter today then the expansion would have occured expanding through nothing as nothing existed (as it is believed. So how quickly would the expansion through nothing have occured. Going of at a tangent above but there must be some evidence for finding the centre of the big bang in the form of certain types of matter/unusual graviational forces etc as space is only a oppurtunity to look at what has already happened. Could this still be happening? Was there just one big bang or could there have been a series of bangs to get things going?

And God said, "let there be light" and a big bang occurred and there was light.

God the Father (big) banged Mother Nature.

Apparently the star that exploded to give birth to all that is - and at the risk of sounding redundent I say apparently again - came from the milky way galaxy.

Right smack in the middle.

uranus