**Ask a monkey a physics question thread**

[OngBonga]

Dwell on the fact that there was (from memory) ~ a billion times more stuff in the universe back then.

meaning that of all the mass in the early universe, only ~1 billionth remains.

But the energy still exists. It must do. What happened to that energy? The energy content of the universe is exctly the same today as it was 10^-43 seconds after big bang. And since energy is mass... well that "stuff" just changed, it didn't disappear.

[OngBonga]

How that is not a singularity is not remotely known or credibly speculated.

Seems obvious. A positive number minus a smaller positive number equals a number greater than zero, and a volume greater than zero is not a singularity.

[MadMojoMonkey]

Seems obvious. A positive number minus a smaller positive number equals a number greater than zero, and a volume greater than zero is not a singularity.

The radius of the universe was smaller than the Swarzchild radius for that mass.

Why was it expanding, and not collapsing under the curvature of spacetime caused by that much mass-energy in that small a volume?

[OngBonga]

Why was it expanding, and not collapsing under the curvature of spacetime caused by that much mass-energy in that small a volume?

Umm... because it was rotating at an incomprehensible rate, and therefore inertial forces were of the order required to do battle with gravity? That's my best guess.

It has been transformed predominantly into heat and the gravitational potential energy stored in the curvature of spacetime.

Right, so the energy still exists. The "annhiliation" of the matter and antimatter isn't annihilation in the context of "obliteration", it's to "convert to radiation". So all that matter and antimatter that was annihilating each other in the very early universe, it still contributes to the mass of the universe, because its energy remains part of the system. It's still "stuff".

[MadMojoMonkey]

Umm... because it was rotating at an incomprehensible rate, and therefore inertial forces were of the order required to do battle with gravity? That's my best guess.

My only critique is that IF the universe started as an idealized point mass (not even sure how absurd that is), then the notion that it was rotating is absurd. A thing with no measurable length dimension cannot be said to be rotating in any meaningful way.


***
Just to be clear, this is a separate topic, which we are discussing at the same time.

Right, so the energy still exists. The "annhiliation" of the matter and antimatter isn't annihilation in the context of "obliteration", it's to "convert to radiation". So all that matter and antimatter that was annihilating each other in the very early universe, it still contributes to the mass of the universe, because its energy remains part of the system. It's still "stuff".

Which is true, but doesn't address, "Why, of all the stuff that's left, is there ANY matter, and not just energy?"

"So all that matter and antimatter that was annihilating each other in the very early universe"

Ahem: most of that matter and all of that antimatter

[MadMojoMonkey]

But the energy still exists. It must do. What happened to that energy? The energy content of the universe is exactly the same today as it was 10^-43 seconds after big bang. And since energy is mass... well that "stuff" just changed, it didn't disappear.

Yes. The mass-energy is conserved.

It has been transformed predominantly into heat and the gravitational potential energy stored in the curvature of spacetime.

The point is that matter and anti-matter annihilate each other in pairs by all known observed interactions. There are only hypothetical and unobserved interactions in which matter and anti-matter annihilate at a rate other than 1:1.