EarthSci Flashcards
Compromises all the space, time, all matter and energy in it.
Universe
How many galaxies does the universe have
300-400 billion
What is the name of our galaxy
Milky Way
gas,dust, and billions of star and their solar system, all held together by gravity
Galaxy
How much baryonic matter in the galaxy
4.6%
How much Cold matter
24%
Matter that has gravity but does not emit light
Cold dark matter
How much Dark energy
71.4%
Force that oppose gravity
Dark energy
Unit of astronomical distance equivalent to the distance hat light travels in one year
Light year
light year number
9.4607x10^12 km
A fixed, spherical earth resides at the center of the universe, surrounded by concentric celestial spheres of planets and stars
Geocentric theory
discoverd geocentric theory
Aristotle
Theory that proposes that earth is a planet in motion around the sun
Heliocentric theory
Who discoverd heliocentric theory
Nicolaus Copernicus
toward the red end of the spectrum
velocity-distance relationship
Red shift or doppler shift
discovered red shift
Edwin Hubble
explosion for unknown reasons & began to expand rapidly
Bigbang theory
enormous rotating cloud from which the solar system evolved
Solar Nebula
solar nebula is composed of what
Hydrogen and helium
beging to form from metallic and rockyclumps
Inner planets
began forming from fragment with a high percentage of ices
larger outer planets
is a small, rock body whose diameter can range from a few hundred kilometers to less than a kilometer
Asteroid
pieces of rocky and metallic materials held together by frozen gasas
Comets
Most famous short peiod comet
Halley’s comet
small (sand size) space rock usually left behind from passing comet
meteoroid
a meteoroid burning through the atmosphere (shooting star)
Meteor
a meteor that reaches the earth
meteorite
