Brace yourselves for gravitational waves

[Excited Penguin]

I don't understand. How can it be infinite if it has a starting point from which it expands?

It doesn't have to have that, that's a common misconception. The big bang wasn't an outward explosion that necessarily started in one point.

LOL. I don't get it.

[Excited Penguin]

I don't understand. How can it be infinite if it has a starting point from which it expands?

It doesn't have to have that, that's a common misconception. The big bang wasn't an outward explosion that necessarily started in one point. Since relativity breaks down, and inflation likely took place driven by quantum fluctuations, we cannot trace ut back to size zero anyways, and such a singularity likely never occurred.

I still don't get it. Let me put it a little differently. Did the universe have a size, moments after the Big Bang? Does it have a size now? You can't say something is infinite if it has a size, right?

[Excited Penguin]

Do you know of any good books I could read to understand this better? It seems I'm thinking about it the wrong way.

[Jackie]

[Jackie]

[Jackie]

There is a well defined notion of the spatial extent of the universe, and it is either finite or not. It could however be finite in one direction and infinite in another... All we know right now is that if it is finite, it appears to be bigger than the visible universe (otherwise it would show signatures in the CMB). If there was cosmic inflation, it is likely at least many many orders of magnitude bigger than the observable patch.

Ok, but still, am I wrong since currently we don't know something or nothing or infinite vs finite?

What would be wrong with thinking of nothing being temporary and something being temporary but going from one to the other over and over being infinite? I don't know. It just seems an obvious extrapolation considering everything we see now builds up then eventually breaks down. Why cant what we don't know before, and what we don't know after, simply be a cycle? Seems to be that way now. 

Again, I am no expert of course, but if we are going to postulate one or the other and still admit we don't have that answer, why cant QM give us the third option of both depending on QM POV?

[Excited Penguin]

[Jackie]

[Excited Penguin]

I am only converned with the line in that analogy. The line being the universe. As you said yourself it is finite, and that's all that matters.

Yes, you are getting pedantic.

[Jackie]

I am only converned with the line in that analogy. The line being the universe. As you said yourself it is finite, and that's all that matters.

Yes, you are getting pedantic.

I'm not stuck like some on taking a "we came from nothing" which is fine, or "we came from something" which is fine with me as well. What I do know which is far more important for more people to grow to accept is that humans are not the center of all this. That is my sticking point with theists. No matter what we don't currently know, we do know we don't need a cosmic sky wizard either way..