Chapter 6: Cosmology Flashcards
Two known facts of universe
- two different parts of the universe should look the same
- there is no referee direction, everything looks the same
Big Bang
- was very dense and hot, as universe expanded and cooled down
- matter was created; electrons, photons, positron
- two gamma rays together to create things
- every particle has its anti pair
- protons and neutrons creates I’m 8/10 s after Big Bang
- particle and anti-particle kill each other and produce 2 gamma rays
- the more massive particle is the harder it is to form
PN chain
-take proton and neutron: deuteron and light —> deuteron and deuteron—> helium 3–> helium
In how long was universe created
15 mins everything in universe was created
-just left us with hydrogen helium, and protons
Deuterium
- deuterium is very hard to make, it can not be made in stars
- measuring the abundance of it tells us how much normal nagger there is in the universe
Recombination
At redshift 1100 the universe cooled to 3000k
- protons, neutrons, and electrons make matter
- matter and light de-couple and universe becomes transparent
Temp of universe
Universe was hotter, smaller, and denser in the past
- temp today is 2.73K
Fate of universe
-universe has to be fast enough to expand it not escape and fall back
Three types of universe
Flat
Close
Open
Fake universe
Plateaus (enough to expand and slow down)
= 1 reaches a steady state (critical density)
- fluc largest 1 degree scale
- spherical space
Close universe
- expands and then goes back
- > 1 Big Crunch, higher density
- flux largest on greater than 1-degree
- flat space
Open universe
Always expanding
- < 1 expanding forever (low density)
- fluctuations largest on half-degree scale
- hyperbolic space
If we assume matter is the only to density
Then we are in a flat universe
But due to dark energy and matter
Dark energy is expanding our universe in an increasing rate
- 70% dark energy
- 25% dark matter
- 5% we can see
