Earth sci lesson 1 Flashcards
compromises all the space time, all matter and energy in it
Universe
universe contains _______ of galaxies of which our milky way galaxy is one
300-400 billion
gas-dust and billions of stars and their solar systems, all held together by gravity
Galaxy
Galaxy is composed of
4.6 % Baryonic Matter, 24% Cold Dark Matter, 71.4 % Dark energy
matter that has gravity but does not emit light
cold dark matter
force that opposed gravity
dark energy
a large spiral galaxy which is about 100,000 light years wide and 10,000 light years thick at nucleus
milky way
unit of astronomical distance equivalent to the distance that light travels in one year
Light Year
1 light year in km
9.4607 x 10^12 km (nearly 6 trillion miles)
oldest known planet in the milky way
methuselah or genesis planet
age of methuselah
12.7 billion yrs old
age of universe
13.77 billion yrs old
age of milky way
13.51 billion yrs old
age of solar system
4.57 billion yrs old
age of earth
4.54 billion yrs old
when celestial body appears to move across the sky each day
apparent daily motion
believed in Geocentric Model/Theory
Plato, Aristotle, Ptolemy
stationary earth lies in the center and all other celestial objects orbit around it
Geocentric Theory/Model
believed in Heliocentric Model/Theory
Copernicus, Galileo
sun lies in center and other celestial objects including Earth orbit it
Heliocentric Theory/Model
accrdg to the geocentric model of Stagira, a fixed spherical Earth resides at the center of the universe, surrounded by concentric celestial spheres of planets and stars
The Aristotelian Universe
published heliocentric theory
Nicolaus Copernicus
ideas are velocity-distance and red shift
Edwin Hubble
_______ relationship for galaxies expansion
velocity-distance
called doppler shift toward the red end of the spectrum, occurs because the light waves are stretched which shows that Earth and the source are moving away from each other
Red shift
states that the galaxies are retreating from Milky Way at a speed that is proportional to their distance
Hubble’s Law
everything that is now in the universe existed as a single, hot, chaotic mass smaller than an atom 13.77 billion years ago
big bang theory
this mass exploded and began to expand rapidly cooling as it grew All the matter and energy in the universe, and even space and time, resulted from this expansion
Big bang Theory
hypothesis that includes solar nebula
nebular hypothesis
an enormous rotating cloud from which the solar system evolved
solar nebula
about ______ years ago, the nebula began to contract
5 billion
composed mostly of _____ and ______
hydrogen and helium
assumed a flat, disk shape with _____ at the center
protosun (pre-sun)
begin to form from metallic and rocky clumps
Inner planets
began forming from fragments with a high percentage of ices
Large outer planets
5 minor members of Solar System
Asteroids, Comets. Meteoroid, meteor, meteorite
icy body that releases gases as it orbits the Sun
Comet
most famous short-period comet
Halley’s comet
orbital period of Halley’s comet
76 years
rocky or metallic fragment of an asteroid, comet or planet
meteoroid (in space)
streak of light (shooting stars) seen when a meteoroid heats up in the atmosphere
meteor (in atmosphere)
meteor fragment that reaches the ground
meteorite (on earth)
