1. 93 Billion Light Years Across
2. Milky Way is 100,000 light years across
3. Galaxies consist of stars and some other planet systems
4. About 13 billion years old

1. 73% dark energy
2. 23% cold dark matter
3. 4% regular matter

1.  Matter began in one spot and then explode and spread around
2. Galaxies formed from this matter

1. A space where the gravitation field is so powerful that everything, including light, is pulled into it
2. Objects enter the surface, event horizon, and cannot escape

1. Quasi-stellar radio source
2. Energetic Galaxy with an active galactic nucleus
3. Lots of light and radio waves

1. Has not been proven, may account for large amount of universe mass
2. Undetectable because it does not emit radiation
3. IS believed to exist because of gravitational forces exerted on visible objects

1. Consist of stars, stellar remnants, and dark matter
2. Gravitationally bound
1. Stars, star systems, gases, and dust orbit the galaxy center
2. Around 100 billion exist in the universe

Dwarf ~ 10 Million Stars

Giant ~ 1 Trillian Stars

1. Four minutes shorter than a solar day
2. Measured against a distant fixed star

1. Distance from Earth to Sun
2. 150million KM or 93 Million Miles

1. Distance light travels in a vacuum in one year
2. 1 Light Year = 64,341 AU

1. Parallax of one arcsecond
2. 3.26 light years
3. Calculate distances by triangulation
4. AU Distance from the Sun is used to form the side of a right triangle

Small Red Dwarfs: 100s of billions of years

Massive Hot SuperGiants: Millions of Years

Sun (mid sized Giant): 10 billion years

Aftewards it will expand into a red giant, then either a black dwarf or a small white dwarf
Massive Stars become red supergiants (sometimes blue)

Then explode in a supernova, then become neutron stars.

Largest become black holes

1. Cloud of dust and gas that is composed primarily of hyroden (97%) and helium (3%)
2. Gravity causes them to clump together
3. If nuclear fusion of hyrdogen into helium begins a star is born

1. Stars use Morgan Keenan Classifcation
1. Hottest to Coolest
2. O(blue), B, A(white), F, G(yellow), K, M(red)
1. "Oh be a fine guy, kiss me"

1. Center of our solar system
2. 70% Hydrogen 28% Helium 2% metals
3. 99.8 of our solar system's mass
4. Surface is photosphere

Meteor: A streak of light when a a meteoroid in the atmosphere

Meteoroid: A rock from space before it enters earth's atmospohere

Meteorite: rocks that reach earth's surface from space

Eclipse of the Moon: During full moon phase

Eclipse of the Sun: During new moon

1. Waxing
1. About two weeks form New to Full Moon
2. Phases
1. New Moon
1. Not Illuminated
2. Crescent Moon
1. Tiny Sliver
3. First Quarter
1. Half the moon
4. Gibbous
1. More than half
5. Full Moon
1. Fully lit
6. Then the moon is waning

1. Tropic of Cancer
1. 23.5 degrees north
2. Sun is directly overhead at noon on June 21st summer of Northern Hemisphere
2. Tropic of Capricorn
1. 23.5 degrees south
2. Sun is directly overhead at noon on December 21st, Winter in Northen Hemisphere

Lattitude: North South

Longitude: West East