Did the early universe plasma stay plasma for 380,000 years?

[Kylie87]

Hello,

In the early stages of Cosmic Inflation, immediately after the Big Bang, all matter was basically energy in a plasma form. It continued to expand for 380,000 years before cooling enough to form the first atoms. I have two questions:

1. Did this matter continue to exist in a plasma state for that entire 380,000 years?
2. Did that plasma continue to expand at a constant rate for that entire 380,000 years?

Thanks,
Kylie

 

[phinds]

Your title question is about inflation and then your actual question is about expansion. They are different.

Inflation is a proposed, but not fully known to be actual, "expansion" at a rate that defies human understanding and is hypothesized to have occurred during a very tiny fraction of a second after the singularity. It solves several known issues with how the universe has formed.

Following inflation, the universe has been expanding (THIS is "expansion") ever since.

About 5 billion years ago a non-understood force (or SOMETHING) that is called "dark energy" for want of a better name, started to overcome the gravitational slowdown of the expansion and caused the expansion to accelerate, which it is still doing.

For exactly what happened at 380,000 years, Google "surface of last scattering". It was not a change in the rate of the expansion but at change in the opacity of the plasma ("let there be light").

 

[mfb]

1. Did this matter continue to exist in a plasma state for that entire 380,000 years?

Neglecting the first seconds, it did.

2. Did that plasma continue to expand at a constant rate for that entire 380,000 years?

No, expansion slowed down during that period (and the following billions of years - accelerated expansion is a relatively "new" effect).

 

[Kylie87]

Thanks for the answers. Mfb, if it was not a plasma for the first seconds, what was it?

 

[mfb]

Not a plasma of nuclei, electrons and photons.
Before that, it was a plasma of nuclei, electrons and positrons and photons, and before that, it was a quark-gluon plasma.
Timeline

 

[Kylie87]

Thanks heaps for that. It's just amazing to think that the universe was so basic in the early days; just energy really. Still, the biggest question of all still remains, which is why the big bang happened in the first place, and what was before it?