stars Flashcards
astronomy
The study of the universe
light year
The distance traveled by light in one year
size order from largest to smallest (components of the universe)
universe, galaxy, solar system, star
universe
All of the matter and energy in space known existence, 13.7 billion, made of billions of galaxies
galaxy
A group of hundred of billions of stars held togther by gravity
characteristics of our galaxy
spiral shaped galaxy, located in the middle of an outer arm
Big bang
The universe began when an extremely dense concentration of matter exploded and was distiruibed
Across the universe
the universe is still ____ and ____ from this explosion
cooling and expanding
evidence of big bang
cosmic background radiation, red shit of light from distant galaxies, blue shift, red shift
cosmic microwave background radiation
evidence of big bang, The universe is still cooling from the initial explosion. Empty space should have a temp of absolute zero,
But it actually is 3k
red shift of light from distant galaxies
evidence the universe is expanding (doppler effect: the apparent change in wavelength of an energy source that is moving)
blue shift
evidence of the big bang, if galaxy is moving towards an observer light waves are compressed and they decrease the wavelength
red shift
if a galaxy is moving away the light waves are stretched and they’re increasing in wavelength
closed universe
If the mass of the universe is large enough it will eventually start to contract due to gravity
open universe
If the mass of the universe is smaller it will expand forever because there is not enough gravity to halt its expansion