The Solar System(A Pitifully Brief Tour)

The Suns Family

Formed from a Solar Nebula 4.5Gyr agoCourtesy Penn State

MercuryRo = 35 Mil. Miles3000 miles in diameterLunar-like surfaceSurface temp 800oFYr = 88 daysDay = 59 Earth daysLarge iron interiorRo is orbital radius

VenusRo = 67 Mil. MilesClose to Earths diameterShrouded in cloudsTemp 900oFGreenhouse effectYr = 243 daysDay = 248 Earth daysRetrograde rotation

Radar image of surface

MarsRo = 140 Mil. MilesHalf Earths diameterThin CO2 atmosphereAve. Temp -81oFTwo Moons, Phobos & DeimosYr = 2 Earth yearsDay = 1 Earth Day

JupiterRo = 500 Mil. Miles10.5 Earth Diameters316 Earths to fill-180oFMostly gasH, He, then some N3, CO2, CH3Zonal flows63 Moons (as of 6/08)Sparse ringsYr = 11.9 Earth yearsDay = 10 hours

SaturnRo = 940 Mil. Miles9.4 Earths in diameter-218oFMostly gasH, He, then some N3, CO2, CH360 MoonsAwesome ringsYr = 29.6 Earth yearsDay = 11 hoursTwo moons are visible

Rings-Roche LimitThe distance from a planet where the tidal forces on a moon can tear it apart, forming a ring

Rings-CollisionRings can form when a moon is impacted by another moon , asteroid, or cometMimas (right) was hit by something that almost destroyed it

Rings-Contributions/BurglarySome moons eject material into a ring systemEnceladus (right) contributes to Saturns rings with a ice geyserSome planets scrap material off a moon

UranusDiscovered in 1781Ro = 1.8 Bil. Miles4 Earths in diameter-323oFMostly gasH, He, some CH3Weak rings27 MoonsYr = 84 Earth yearsDay = 17 hours

NeptuneDiscovered in 1846Ro = 2.8 Bil. Miles3.9 Earths in diameter-323oFMostly gasH, He, some CH3Very weak wings13 moonsYr = 165 Earth yearsDay = 16 hours

Pluto and the Ice DwarfsDiscovered in 1930, demoted in 2006New definition for planets:Orbit the SunSphericalSweep out all material in their orbitsIce dwarfs orbit in the Kuiper Belt30-55 AU1AU = 1 Earth orbital radius-380oFOrbital periods of 250 years+

AsteroidsFirst (Ceres) discovered in 180130,000 named, perhaps 750,000+Most orbit in the Asteroid Belt, 2-5AUNEOs cross Earths orbitMost are oblongBiggest are ~ 300 miles in diameterCategoriesStony MetallicCarbonaceousGaspra

CometsDirty SnowballsSome come from Kuiper belt (short period), others from the Oort Cloud (long period)Core ~ 10-25 miles in diameterComa ~ 100,000 miles in diameterTails ~ 1 Mil. MilesIon tailDust tailEvaporate every time they come close to the SunComet West