Unit 2 Flashcards
Kepler’s Laws
1: Planets orbit sun in nearly circular elliptical orbits with one focus
2: Planet’s speed is fasted when planet is closest to the Sun and slowest when its farthest away
3: P^2=a^3 (where p=period and a=AU)
Greenhouse effect
Sun’s energy heats earth, and the surface radiates this heat back toward space via infrared radiation
Comets
Few kilometers in size
Made of ice and dust (remnants of Solar System formation
Tails point away from the Sun
Short period comets: periods of less than 200 years
Long periods can be thousands of years
Asteroids
Remnants of SS formation
Many in the Asteroid BelT
Movement very slowly across the sky to a viewer on earth
Do not shine on their own
Few types: carbon-rich, m
Meteors
Streak across the sky very quickly
Most are tiny dust particles or grains
Occur when an asteroid crosses Earth’s orbit, or when Earth passes through debris left behind by a comet
Jupiter’s moons
Over 50
Four largest: In, Europa, Ganymede, Callisto were discovered by Galileo in the 17th C and used to measure the mass of Jupiter
Io
Closest to planet
Coppery-yellow with black dots representing active volcanic sites
Europa
Water-ice surface without craters
Liquid water ocean below icy crust
Ganymede
Largest moon in SS
Icy crust and craters
Callisto
Furthest out from planet
heavily cratered and hasn’t changed much since its formation
Saturn
Rings discovered by Galileo
mass 100x Earth’s, diameter about 10x Earth’s
Density of 0.7 g per cubic centimeter 9very, very low!)
More than 50 moons!
Titan
Saturn’s moon, 2nd largest moon in the solar system
Very thick nitrogen rich atmosphere, but perhaps too cold for life
Miranda
Uranus’s moon: heavily cratered, with weird valleys of cliffs caused by upwelling of ices
Why isn’t Pluto considered a planet anymore
Other similar objects were found father from the sun
Different from the other outer planets
Kuiper Belt
Disk shaped region beyond Neptune (Pluto lives here)
