Astrophysics And Cosmology Flashcards
Parallax
Measure of how much a nearby object appears to move in relation to a distant background due to observers motion
Astronomical unit
Mean distance between sun and earth
Parsec
1pc is distance from earth to a point that has an annual parallax of 1 Arcsec (1/3600 of a degree)
3.1 x 10^16
Light year
Distance that an electromagnetic wave travels through vacuum in 1 year
9.5x10^15
Stellar Evolution
Nebula to protostar to main sequence
Low mass: 0.5-10 solar mass
To red giant to white dwarf
High Mass: >10 solar mass
Red super giant
Core 1.44-3 solar mass:
Neutron Star
Core >3 solar mass: (Chandrasekhar limit)
Black hole
Wein’s Displacement Law
Wavelength ~ 1/Temperature
Stefans Law
L = 4 x pi x r^2 x stefans constant x T^4
Luminosity
Brightness of star
Total energy emitted by star
Cosmological Principle
Universe is isotropic (looks and measured the same in all direction) and homogenous (matter is distributed uniformly)
Laws of physics are universal
Evidence of Big Bang
Red shift, CMBR (temp now at 2.7K)
Hubbles Law
Recessional Velocity = H0 x distance
Evolution of universe
T= 0
Big Bang
T=10^-43
Temp = 10^27K
I unified force
T=10^-6
Temp = 10^15K
Quarks, anti quarks, leptons, muons
T=10^-4 Temp = 10^12K Quarks make protons and neutrons Antimatter and matter annihilate Matter left over and photons made
T=100
Temp = 10^9K
Electrons formed
Helium nucleus made
T=300,000 years
Electrons and nuclei form elements
Gamma radiation can now move
T=14 billion years
Temp = 2.7 k
Excess matter makes stuff
Dark matter
Galaxies have higher recessional velocity than their given matter
Must be extra matter
But must be dark matter because if it’s normal matter, this counteracts our beliefs regarding how many protons and neutrons their dark as a result of the Big Bang
Dark energy
Expansion of universe is accelerating
Chandrasekhar limit
Core = 1.4 solar mass
Electron degeneracy can counteract the pressure of gravity
