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
stars
Spheres of gas in space that produce their own energy (self-luminous)
nuclear fusion
Process by which stars produce energy. Hydrogen atoms are joined togther to produce helium and energy
life cycles of stars
stars go through a sequence of changes depending upon the size/mass of the star
Nebula/protostar
Stars all begin as large spinning clouds of gas and dust being pulled together by their gravity
main sequence star
This is the stable period, creates energy, and shines brightly. Our Sun is in the Main Sequence stage. Early stage.
red giant
star get much larger and cooler
white dwarf
only the small hot core of star remains
black dwarf
cooled remains of a white dwarf, oldest
solar system
a star and everything that revoloves around it, our solar system is 4.6 billion years old
our solar system is formed as remains of a____
supernova
the dust and gas left outside clumped together to form_____
planetesimals (collided and formed planets)
Planet
any object that directly revolves around a star, has a nearly round shape, and has its own orbital zone
retrograde motion
the motion exhibited by planets when they appear to move backward for a time in comparison to the stars caused by the differences in revolutions around the Sun
terrestrial planets
rocky, small, high density and Earth-like planets
(Inner four planets: Mercury, Venus, Earth, Mars)
jovaian planet
gaseous, very large, low density and Jupiter-like planets (Outer four planets: Jupiter, Saturn, Uranus, Neptune)
asteriods
Irregularly shaped rock that is smaller than a planet and occupies an orbit around the sun
meteroriods
Particles of rock and metal in space ranging in size from a grain of sand to a large boulder. Always smaller than asteroids
meteor
Streak of light produced when a meteoroid enters earth’s atmosphere and burs due to friction of gas molecules
meteorite
a meteoroid or asteroid that passes through earth’s atmosphere and lands on earth’s surface
comet
An object made of ice and rock fragments that revolves around the sun usually in a highly eccentric orbit
