How can you describe the Big Bang as starting from an infinitely small and infinitely dense state...?

All the Big Bang *really* states is that the universe used to be smaller. That's it. It is not a creation story, but an explanation of how the universe has evolved and developed over the last 13.7 billion years. It makes no assumptions about "where" stuff came from nor densities at the very moment of creation. The Big Bang merely evaluates the observations and the data we have acquired, and gives us a relatively complete model of how the universe has behaved since about 10^-30 (that's 0.0000000000000000000000000000001) seconds after the Big Bang. Anything before that point in time, we do not know and cannot measure, because the laws of physics, as we understand them, break down before that time... you reach a mathematical singularity, where we just don't know what happened, and how space, time, matter, and energy behaved, because the laws of their behavior would not have been in place yet.

So, while you are curious as to how "an infinitely small and infinitely dense state" existed, the Big Bang theory cannot take you there. It can get you as far back in the past as we can accurately measure, but does not address the issues you are seeking answers to.

The Big Bang Theory is about 117 years old, or at least the original idea is from then. It has been revised and tweaked and rebuilt because it did not work.

As far as the size of The Primordial Atom goes, remember that The Milky Way was thought to be the entire Universe back then, and so it could be imagined as having been crushed into a pretty small ball. The larger the observed Universe gets, the stranger it is to imagine it all being in one place, but that's not the really bizarre part of the new improved Big Bang Theory...it's that it now takes place in nothing, with all space included inside the ball (and all matter and energy and light, etc.) which is why when you hear about the theory it is about what happens 'after' the bang, because it starts with an impossible fantasy idea...and that's because the theory failed and had to be tweaked, again. If you imagine what we can see so far somehow choosing one point to collapse into, including space (which is not something that can be compressed and it has no push or pull) and light, etc., etc....if that could somehow happen, then how big would the ball be? A ball around 30 billion light years accross compressed down into a black hole like thing? Ah, but then remember that the universe is not a round or oval ball, just our current map of it is.

Check out all the versions of The Big Bang Theory for fun and laughs, including maybe one that says it popped out of another dimension all together, as a way of explaining that infinitely small initial condition.

It's all a myth. Keep on thinking for yourself.

There is much more out there than that old failed idea. And, the story of what is keeping it alive is even more bizarre than the theory itself. It's stranger than fiction.

Yes, it would.

The reason so many people refuse to do that is it deprives them of the weasel words they use to shore up the idea of singularity.

There is no such quantity as "infinite." It's not a number, it's a direction you count in. Calling something "infinitely small" or "infinitely dense" tries to call a counting process a quantity. It's a slick trick to paper over the fact that if there ever was any point of origin of "the universe," physics completely lacks the tools to describe it. All it can even try to describe is events after the origin.

If they were honest and said what they really meant, "zero volume," they'd have to admit there's no such thing as density at that point. But they want to make money and be famous. If you're telling people about the world, they want to hear a story, and they won't pay you unless your story has a beginning. That's why they say things like "singularity."

An object of that should have infinite gravitational force as well, so I don't even understand how it could begin expanding in the first place. I thing it more likely a collision two object. Perhaps anti-matter and matter? Or perhaps two objects made of all this dark matter we can't see. If we can "re-create" the big bang at CERN in the LHC, then why wouldn't a collision model work in relativity? It seems an expanding singularity is an oxymoron. Perhaps a normal black hole and a black hole made of anti-matter collided? A singularity is what is at the center of all black holes, so how can the grand daddy of all singularities just suddenly start expanding?

A finite amount of mass compressed into an infinitely small space would have an infinite density. That's the principle behind singularities

of what POSSIBLE reference could the fact that "at the current momemt" there is a finite amount of mass in the universe be? Completely ASIDE from the fact that energy and mass are interchangeable, you dont know how long the universe will last.

so you've never taken calculus, have you? what would the limit be?

lim_{x \to \infty} f(x) = ??

as the volume OR the density approaches infinity, whats the LIMIT of the function f of x?

the Big Bang isn't infinitely small or infinitely dense, but its density and smallness is so intense that it's described as infinite simply because in human comprehension, they would produce the same reactions.

Here is a good description http://www.ugcs.caltech.edu/~yukimoon/BigBang/

http://universemass.blogspot.com/