Download 2nd Planet from the Sun

Venus
2nd Planet from the Sun
Q: How did Venus Get its name?
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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
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Phases of Venus
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The 1st 2 pictures were taken 10 days apart
with a 16 inch telescope
Basic Information
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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?
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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
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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
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Pancake Volcanoes?
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Magellan (a probe sent in 1989) found oddshaped volcanoes formed by thick lava
collapsing over old magma chambers
Shield Volcanoes
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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?)
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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)
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Venus missions cont...
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Soviet Venera 9 - 1st surface photos
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Most recently Magellan mapped Venus
(1994) then was sent to the surface to study
aerobraking techniques to save fuel for
future missions