phys 277 test 3

obler's paradox

is you look anywhere there should be a star/galaxy

spin flip transition

an excited electron who's spin is alligned with the proton will eventually flip and its spin to a lower energy state, occurs at 21 cm radiation

fritzwiki?

discovered dark matter, people didn't believe him, 40% more mass then was accounted for in the galaxy cluster

theories the prove matter dark matter

galaxies moving around clusters (mass)
lots of hot gas moving around the cluster(gas is not escaping)
gravitational lensing amount of lensing equals the mass

critical density

5% ordinary matter, 25% dark matter, 70% dark energy, universe is flat

dark energy

a theoretical energy that is a negative mass and causes things to move away from it, like anti gravity

freeze out

the forces seperate

GUT Theory

Grand unified theory, theory of everything

328,000

we can study from this point in time upwards

Cosmic Backgroudn Radiation

leftover heat from the big bang, graph it out, looks like a perfect thermal radiation curve/baclbody curve 2.37 k

cbr map

shows density of the cosmic web and proves inflation

inflation

explains yhe large quantum mass and why the universe appears to be flat

not everything is in visable light

why is the sky dark at night

antimatter

1 extra matter particle, photon

cosmological constant

enstien added a fudge number, but ended up keeping it in to account for dark matter, dark energy, and the expanding universe.

21 cm line

hydrogen emits this on this spectrum

wimps

weakly interacting massive particles

universe is expanding

redshift in white dwarf supernovas

hubbles constant

relation between the velocities of remote galaxies and their distances. It expresses the rate at which the universe is expanding.

5 min

Approximately how long after the Big
Bang did the era of nucleosynthesis end,
marking the time when the basic
chemical composition of the universe was
determined?

380,000 years

When did the photons in the cosmic
microwave background first travel freely
through the universe?

gets less dense and cool

In general, what happens to the
density and temperature of a gas as it
expands?

3 k

temp of the universe as a whole

plank era

all four forces are one

Electroweak era

forces seperate out, causes rapid expansion

rotation curve

a graph showing how orbital velocity depends on distance from the center for a spiral galaxy