Overview of the Solar System
The Sun
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Big Ball O' Gas: 71% Hydrogen, 27% Helium, 2% heavier elements
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Radius = 7x105 km (~100 Earth radii)
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Mass = 2x1030 kg (~300,000 Earth masses)
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Energy from nuclear reactions: hydrogen fusion into helium.
The Planets and their Satellites
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The Terrestrial Planets: Mercury,
Venus, Earth, Mars
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innermost planets
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smaller, rocky bodies (densities 4.0 - 5.5 g/cm3)
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complex atmospheres: CO2, H2O, N2
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The Jovian Planets: Jupiter, Saturn,
Uranus, Neptune
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more distant
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large, gaseous bodies (densities 0.7 - 1.6 g/cm3)
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primordial atmospheres: H, He
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and Pluto
Asteroids
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Small, rocky bodies (several thousands known)
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Most lie in a belt between Mars and Jupiter
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Up to 1000 km in size (most much smaller)
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Total mass is less than that of the Moon
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When small ones enter Earth's atmosphere, we get meteors
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When big ones enter, we get Hollywood movies!
Comets
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Small, icy bodies
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Tails form when they interact with the Sun
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Travel on highly elliptical orbits
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Live in very distant regions of the solar system
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Primordial objects