Astrophysics Flashcards
Define a universe
large collection of billions of galaxies
Define a galaxy
large collection of billions of stars
Which galaxy is our solar system in?
The Milky Way
What force keeps planets and moons orbitting ?
gravitational force
Moons orbit ….
planets
Planets orbit ….
stars
Artificial satellites orbit the….
earth
Comets orbit the …..
sun
The gravitational field strength of an object depends on its …
mass
more massive means larger gravitational field strength
Equation: orbital speed =
orbital speed = 2 pi r / T
What are the stages of evolution for a star of similar mass to our sun?
Nebula
Main sequence star
Red giant
White Dwarf
What are the stages of evolution for a star of bigger in mass than our sun?
Nebula
Giant Main Sequence Star
Large red giant
Supernova
Black hole (neutron star)
What do we use to measure the brightness of a star?
Absolute magnitude - measure brightness by comparing stars at a standard distance away
Can you draw a Hertzsprung Russel diagram and what is unusual about it’s x axis
temp of star on x axis
brightness on y axis
temp axis runs in the opposite direction
What are the main arguments in favour of the big bang theory?
Universe is still expanding, evidence from:
red shift or galaxies and stars
cosmic microwave background radiation
The further away the galaxy, the greater the red shift
What is the doppler effect and red shift?
Stars moving away from an observer the apparent frequency of light seen will be lower - shifted to the red end of the spectrum
Redshift, doppler equation?
