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Transcript
Venus 2nd Planet from the Sun Q: How did Venus Get its name? ◗ A: Venus was named for the goddess of love and beauty Like Mercury, Venus was also originally thought to be 2 different planets They were called Eosphorus (morning star) and Hesperus (evening star) ◗ Venus is the 3rd brightest object in the sky (besides sun & moon) ◗ Because Venus is an inferior planet (between us and moon), it has phases as Galileo observed ◗ Phases of Venus ◗ The 1st 2 pictures were taken 10 days apart with a 16 inch telescope Basic Information ◗ ◗ ◗ ◗ ◗ Located ~ 65 million miles from Sun Venusian year (period of revolution) = 225 days Venusian day (period of rotation) = 243 days A day on Venus is longer than a year! It is ~ the same size as Earth (7200 miles in diameter) but slightly less dense Q: What is it like on Venus? ◗ ◗ ◗ ◗ ◗ A: Very unpleasant! Completely covered with clouds of sulfuric acid hottest planet in solar system avg = 900 ° F (hot enough to melt lead) Why? because the atmosphere contains greenhouse gases like CO2 that trap heat Venus’ Surface Clouds make atmosphere so dense that air pressure is the same as being half a mile underwater ◗ Venus is also very windy (avg = 240 mph) at the cloud tops but relatively slow at the surface ◗ Q: What does the surface of Venus look like? It’s dry - no water (it boiled away long ago) ◗ Most of Venus is covered with rolling plains with a few mountains ◗ Much of the surface is covered with lava flows ◗ Pancake Volcanoes? ◗ Magellan (a probe sent in 1989) found oddshaped volcanoes formed by thick lava collapsing over old magma chambers Shield Volcanoes ◗ Although Venus has a few pancake volcanoes, the majority are just the more familiar shield volcanoes (large, broad and slightly domed) Venus’ Story Cont…. There are very few craters (most meteorites burn up in the atmosphere) ◗ It has an iron core but no magnetic field probably because it rotates so slowly ◗ Alas poor Venus also has no moons ◗ (although between 1672 & 1892 several astronomers reported seeing a moon perhaps an asteroid or nova?) ◗ Q: Who has been to Venus? There have been over 20 missions to Venus ◗ 1st was Mariner 2 in 1962 (found temp and cloud cover) ◗ Soviet Venera 7 (1st to land on another planet) ◗ Venus missions cont... ◗ Soviet Venera 9 - 1st surface photos ◗ Most recently Magellan mapped Venus (1994) then was sent to the surface to study aerobraking techniques to save fuel for future missions