M5.5 Cosmology Flashcards
Why do near galaxies not follow hubble’s law trend lines
because they experience a stronger force of attraction due to gravity
Why do distant galaxies not follow hubble’s law trand lines
because expansion of the universe may not have been constant
what is the cosmological principle
On large scales ther universe is uniform
homoogeneous - constant density
isotropic- symmetrical
what is the life cycle of a star around the size of the sun
Nebulae
protostar
main sequence star
red giant
white dwarf
black dwarf
life cycle of a star around 10 times the size of the sun
nebulae
protostar
main sequence star
red supergiant
Super Nova
Neutron star
Life cycle fo a star 25 times the mass of the sun
Nebulae
protostar
main sequence star
red supergiant
Super Nova
Black hole
how does a neutron star happen
Main sequence star around 10 times the mass of the sun
the supernova’s core remains intact
when all the fuel is used up the core cools down and the mass of it causese the electrons to fuse with the protons making Neutons
properties of a neutrons star
very dense
rotating very quickly
faster the smaller it is
only made of neutrons
emits specific EM waves
How does a black hole occur
when the white dwarf after the super nova is greater than 2.5 solar masses
thought to almost be a neutron star with infinite density
gravitational field strong enought to trap light
what is a quasar
thought to be galaxies in formation with black holes at the centre
what is a nebula
greater force of gravity hence cloud
increase in temperature
what is a protostar
not hot enough for fusion
continues to attract mass
what is a main sequence star
more density and temperature
Hydrogen fusion can take place
stable pressure and gravity equal
what is a red giant and a red super giant
core mostly helium
collapse because not hot enough to fuse helium
outer core is hot enough to fuse hydrogen causing and expanse
cools and contracts until there is just helium left
helium is fused
if red super giant begins to expand and contract again in super nova
what is a white dwarf
internal pressue exerted by the attms stops the star collapsing any more
no fusion takes place cools down
what is the difference between a white and black ddwarf
black dwarves emit no energy. unlike white dwarfs which are still emitting energy
hwo do dwarf stars not collapse any further
electron degeneracy
two electrons cannot exist in the same place
what is a supernova
a supernova is when the core collapses after the redsuper giant
but it gets hot enough to
what order did the forces split off
Gravity
strong
Weak, Electromagnetic
describe what was before planck time
universe ws infinitely small dense and hot
Between planck time and 10^-4 seconds
unified force
describe the universe 10^-4 seconds after the big bang
10^12 Kelvin
Quarks join to form particles
matter and antimatter annihilate each other
describe the universe 10^2 seconds after the big bang
10^9 Kelvin
similar to the interior of a star
describe the universe 300,000 seconds after the big bang
3*10^3 Kelvin
electrons combine to helium and hydrogen nuclei
universe becomes transparent
What is hubble’s law
recessional speed is proportional to it’s distance from us
How is recesional velocity of a galaxy determined
doppler shifted spectral lines of the light emitted from those galaxies
