Is it possible to work out which direction (in relation to the earth) the big bang occurred?

Yes. You look at the position of all of the galaxies, how it all works together, and you can trace all of that data to see the past positions/compositions of everything, to trace back where the theoretical big bang would have occurred.

P.S. however, the nature of how things move around the galaxy do not match the old model of physics. I think we need a greater understanding of dark matter and dark energy (which we did not even know existed until recently) to create an accurate model of what happened. A lot of very bright people are currently looking into this, and then explaining bits of it on TV using analogies about propellers on the end of propellers and etc that confuse the hell out of us normal people.

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Originally Posted by colbtech

Is it possible to work out which direction (in relation to the earth) The big bang occurred?

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Actually, it didn't occur anywhere while at the same time occurring everywhere at the same time. That is of course if we accept The Big Bang is an accurate explanation for the beginning of the universe. Sounds a bit strange but we need to appreciate that an instant before The Big Bang there was no direction one way or the other because there was no space and time.

We can only talk about location because we live in a 3 D world. Up, down and across. It doesn't make any sense to say The Big Bang occurred so many light years toward a certain point in the universe. Once The Big Bang occurred then space and time were created but not before.

I can understand that it is reasonable to assume it must of occurred somewhere. If it did, it didn't occur anywhere in our 3 D universe. Did it occur in some other strange dimension? Possibly.

Tut

To amplify on Tut's response - the Big Bang occurred right where you are at this very instant. And everywhere else too. So in a way we are all located at the center of the universe.

Here's a 2D analogy that might be helpful: imagine a round toy balloon with spots painted on it. As you blow up the balloon and it expands the spots all move away from each other. Each spot will see that the other spots are moving away, at a rate that is proportional to the distance between the spots (distance as measured along the surface of the balloon). No one spot can claim to be at the center of the expansion, as all spots are moving away from all others.

This is analogous to what we see with the expanding universe - distant galaxies are moving away from us at a rate that is proportional to their distance away (Hubble's Law), and there is no center to this expansion.

?? Confusing. Where is Carl Sagan when you need him?

Surely if galaxies are moving away from us, they don't change direction (significantly), so is it reasonable to assume that as these galaxies are moving away from our perspective, it is also moving away from the original bang?

Or are there galaxies approaching us (our galaxy) from different directions, which would indicate multiple big bangs?

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Originally Posted by colbtech

Surely if galaxies are moving away from us, they don't change direction (significantly), so is it reasonable to assume that as these galaxies are moving away from our perspective, it is also moving away from the original bang?

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Yes - galaxies are moving away from our perspective. And if you could travel to some distant galaxy a few million light years away it would appear that all galaxies would be moving away from your new location as well. (side note - the observed motion of galaxies away from us follows Hubble's Law, which states that the further away a galaxy is the faster it is receding. But for close-by galaxies, like Andromeda, the random local motion of the galaxy is larger than the recession velocity predicted by Hubble's Law, so Andromeda is actually approaching us, not receding.)

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Originally Posted by colbtech

Or are there galaxies approaching us (our galaxy) from different directions, which would indicate multiple big bangs?

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As noted - there are galaxies that are approaching us, but they are nearby. There is no evidence of distant galaxies that do not follow Hubble's Law.

Thanks folks and my apologies for taking so long to reply. While I think I am reasonably intelligent (compared to an amoeba maybe) it is difficult to imagine (at one time) space as not existing. The original question came about because of Andromeda swallowing up our galaxy in 4½ billion years time or so. Just about the time when our sun runs out of fuel!!

Boy is that going to be a bad day! LOL

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Originally Posted by colbtech

Boy is that gonna be a bad day! LOL

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Welcome back Colbtech! The sun running out of fuel will not be pleasant, though the earth will be long gone before then (consumed in the heat of the sun as it evolves into a red giant).

As for Andromeda colliding with the Milky Way - it's impossible to know what the effect would be on the solar system. Remember that in the spiral arms of the galaxy stars are on average several light years apart, so there's lots of empty space. Unlikely there would be actual collisions of stars, although if the galactic cores collided things could get interesting.