L14 - Because of slightly closer distance to Sun, start out...

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11/19/09 Mercury: (0.4 AU) - Very elliptical orbit - Orbit: 88 days - Spin: 59 days - 3:2 spin-orbit resonance: more spins on axis 3 times for every 2 orbits (years) - Greatest elongation: when planet appears farthest from Sun Merc 28° g * E (2 hours): at most visible before/after sunrise/set - Caloris Basin – last great geologic event on mercury giant impact crater - Ripples went through planet, formed “weird terrain” exactly opposite it - Magnetic field weak but present (mystery) Venus: (0.7 AU) - Greatest elongation: 47° (3 hours) - Brightest object in sky (10x brighter than Sirius) - Obscure phases: also appears larger/smaller, based on distance to Earth - Orbital period: 225 days - Spin: 243 days retrograde motion - 5:1 (Earth-Venus resonance) - Coincidence off by few hours - Runaway Greenhouse Effect Very similar to Earth for first billion years or so
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Unformatted text preview: Because of slightly closer distance to Sun, start out slightly warmer (15-30 K) Outgases: CO2, H2O Less H2O condense on surface More H2O in atmosphere, more CO2 in atmosphere H2O + CO2 both greenhouse gases Slightly higher greenhouse effect More H2O evaporates More H2O + CO2 in atmosphere After time, too hot for water to exist as liquid 96% CO2, 3.9% N UV hits H2O in atmosphere, releases H2 + O, H2 escapes atmosphere, O combines with other elements-Venera, Pioneer Venus, Magellan radar mapping, landers (melted in one hour)-Continent type features (~8% of planet vs 25% on Earth, 27% lowlands, 65% rolling plains)-All surface features named after famous women, goddesses, mythological figures, famous wome...
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This note was uploaded on 02/17/2010 for the course PHY 115 taught by Professor Weinbeck during the Spring '09 term at BC.

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