AST 111 Lecture Notes - Lecture 15: Solar Thermal Collector, Boiling Point, Venus Express
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AST 111-Lecture 15 (Taken by a friend, because I was absent)
Ch. 11-6: The dense atmosphere of Venus and the thin Martian Atmosphere
are dramatically different but have similar chemical compositions.
The Atmospheric pressure at the surface of Venus is 90 times larger than Earth's
The equivalent found under 1km of water on Earth, at 490 ºC
Spacecraft usually only live for a few minutes
Because Venus rotates so slowly it’s air patterns are radically different than Earth’s
Heat from the sun warms the equator of Venus and then the heat travels
outward, but on Earth, a faster spin, weather patterns and the Coriolis effect
prevent that from happening
Solar heating does produce fast wind speeds in the upper clouds
350 km/h so clouds can circle the planet in 4 days (consider that it takes
Hurricanes that long to travel across one country)
ESA launched Venus Express mission recently to uncover many unusual
characteristics of the planet’s atmosphere like weird-ass polar vortexes
The Martian atmosphere is mostly CO2 but very thin
Atmospheric pressure is less than 1% of that on Earth
As result temperature variation is HUGE
There is small quantity of H2O vapor in the atmosphere which can condense to
form clouds of water ice crystals...
But liquid water simply CANNOT EXIST on the surface of Mars Today. Why?
Pressure. The boiling point of water varies from place to place on Earth depending
on how cold it is. If it takes a long time in Denver, then imagine on a place so cold
or hot that water can only exist in ice or vapor form. AKA, Mars
There is also a small amount of Methane (CH4) in the atmosphere
This might be a result of the geologic process
OR it could be a biologic process? Maybe.
At times, Mars can kick up huge amounts of Dust to form Dust Devils but like on a
much larger scale
Chapter 11-7: The atmospheres of Venus and Mars were very different
billions of years ago
Because the Earth has an active system of plate tectonics and volcanism...