31 - Astronomy and cosmonolgy Flashcards
Define luminosity
the total radiant power emitted from a star
Define standard candle
an astronomical object of known luminosity
Define radiant flux density
the radiant power passing normally through a surface per unit area
Radiant flux density equation
F = L/4πd^2
Define black body
an idealised object that absorbs all incident electromagnetic radiation falling on it. it has a characteristic emission spectrum and intensity that depends only on its thermodynamic temperature
Wien’s displacement law
λT = constant
λ ∝ 1/T
Stefan-Boltzmann law
L = 4πσr^2T^4
Define Big Bang theory
a model of the creation os the universe from an extremely hot and dense state and its subsequent evolution
Define redshift
a term used to describe the increase in the observed wavelength of the electromagnetic waves due to recession of the source
Define Hubble’s law
the recession speed of a galaxy is directly proportional to its distance from us
Hubble’s law equation
v = Hd
