Planets

Types of Planets Inner (Terrestrial) –Small –Rocky –Closer to sun (faster orbits) –Thin atmospheres Outer (Jovian) –Very large –Thick atmosphere (H, He, methane) –Distant from sun (longer orbits) –Rings Photos from:

Mercury 88 day revolution 59 day rotation Very small Weak mag. Field. Day: 400 °C; Night: -200 °C Little to no atmosphere No moons

Venus 225 day revolution 243 day rotation (1 day is longer than 1 year) Dense Atmosphere (CO 2, Sulfuric acid) –Intense greenhouse effect 475 °C day temp (hottest planet) No moons

Earth 365 day year 24 hr. day Temp allows for s, l, g water 1 moon

Mars 687 day revolution ~24 hr day Tilt is similar to Earth’s = 4 seasons Weak or no magnetic field Day: 27 °C; night: -127 °C Mt. Olympus – largest volcano in Solar System, 26 km tall, extinct 2 moons

Meteorites/Asteroid Small rocky objects Commonly found between Mars and Jupiter 10’s of thousands are known Most are the size of pebbles and are spaced far apart ~220 are > 100 km across Up to 1,000,000 are expected to be in orbits that may cross Earth’s Gaspra Ida 52 km 17 km

Known positions of asteroids in the inner Solar system

Jupiter Largest planet 11.9 year revolution ~10 hr. rotation Strong magnetic field – solid or liquid ‘core’ Radiates more heat to space than it receives. Great Red Spot – severe storm system 62 (!) moons

Saturn 30 year revolution ~10 hr. rotation Lowest density of all planets –Less than 1.0 g/cm3  would float in water Weaker magnetic field than Jupiter Spectacular Ring System 33 (!) moons

Uranus 84 year revolution 17.2 hr. rotation -200 °C surface temperature Tilted on side, magnetic field is not 27 moons

Neptune 165 year revolution 16.1 hr. rotation -225 °C surface temp. Methane gives blue color Also tilted on side Sometimes 9 th planet (if Pluto’s orbit comes inside Neptune’s) 13 moons

Pluto 9 th (or 8 th ) planet 248 year revolution 6.3 day rotation Smallest – only 2800 km diameter –Smaller than Earth’s moon -235 to -210 °C temperature –Frozen atmosphere 1 moon