space is shit Flashcards
what is a white dwarf
core left behind by a red giant
what is light intensity
radiant power per unit area
what is hubble’s law
recessional speed of a galaxy is proportional to its distance
what is meant by the big bang
the universe started off as a dense singularity
name some observations that support the big bang
microwave background radiation; galaxies are receding from each other
state the cosmological principle
the universe is homogenous (evenly distributed) and isotropic (same in all directions), and the laws of physics apply everywhere
what are the properties of a black hole
very dense; light can’t escape its gravity
describe the evolution of a large star
hydrogen runs out; outer layers expand, forming a red supergiant; core collapses, causing a supernova; either a neutron star or black hole is left behind
describe the evolution of the universe from the big bang to present day
started very hot and dense; expansion led to cooling; quarks and leptons formed; quarks combined to form hadrons; hadrons combined to form atoms; atoms combined due to gravity to form stars and planets
what does an absorption spectrum look like
dark bands on a continuous spectrum
describe the formation of a main sequence star
gas cloud is brought together by gravity; temperature increase due to conversion of PE; fusion occurs; stable when gravitational pressure = radiation pressure
describe the characteristics of a white dwarf
very hot and dense; no fusion reaction; collapse prevented by electron degeneracy pressure
explain what it means for the universe to be homogenous
it has constant density throughout
explain how an absorption line is produced on a spectrum in terms of photons and electrons
electrons absorb photons; so move to higher energy level; if E = hf matches energy difference; photon remitted in different direction; dark band formed on continuous spectrum due to absorption
