Thread: If matter cant be created or destroyed, where did all this stuff come from?

Originally Posted by Invader

My confusion stems mostly from:
"So it could have found itself where the mass-energy was diffuse enough for some effect to cause further expansion."I'm still bugged out about how anything can be 'diffuse' or even really exist 'inside'
a dimensionless point at all. Or, perhaps my confusion is about the nature of
singularities. That they're dimensionless is only what I've been taught. Everything
that happened immediately after the big bang (within the fraction of a second) is
merely imagined via thought experiments, right? Or have we proved anything about
the nature of a singularity?

We don't know much about singularities because, by definition, a singularity is where math breaks down. Where a curve intersects itself is called a singularity if you are doing algebraic geometry. Where a coordinate transformation has all partial derivatives equal to zero is a singularity if you're doing differential geometry. Where something goes to infinity is a singularity pretty much no matter what you're doing.

On the whole, I think that we can confidently say that a singularity being a zero dimensional point is a bunch of bullocks that will be done away with by a theory of quantum gravity. Very small? yes. Infinitely small? not possible. The reason that we need quantum gravity is that gravity normally plays no role in quantum physics because the masses involved are small enough for the gravitational charge to be negligible. Gravity is weak. Just pick something up with a magnet to demonstrate this. The tiny little magnet is more powerful than the gravitational attraction of the entire earth.

From the other side, where gravity is dominant, things are usually too large for quantum effects to come into play. From the perspective of quantum mechanics, you are a wave and the wave length is your momentum divided by your mass. So it's a very small wave length and completely negligible. The wave length essentially determines the uncertainty. Gravitational physics describes you just fine.

In what is now a singularity according to our mathematical models, both influences are too large to be ignored and nobody knows how to really take them both into account at the same time. If/When we get there though, I'm almost positive that the whole singularity thing will disappear.

EDIT:

As far as the whole thought experiments thing goes, it's more like after the fact fiddling of the equations. For example, somewhere around 10^-32 seconds after the BB, there needs to have been very rapid "inflationary period" or the math says that the universe comes out completely differently than it actually does. So physicists insert a new field to make it happen or try to get the vacuum energy to be accountable for it. If you actually get into it and look at a lot of sources, there is more of that going on than is often covered in 'popular' accounts. This is one of the reason that I don't consider the big bang to be a fact in the same sense that evolution is. At this point one believes in the big bang and accepts evolution. Quantum gravity could change the game entirely. That being said, it is the best theory that we have right now and if you don't want to believe in it and still be educated, you have quite an uphill battle.