NATS 1570 Lecture Notes - Lecture 21: Ishtar Terra, Aphrodite Terra, Volcanic Gas
15 Apr 2020
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Venus has an interior that is likely very similar to Earth's.
Although we don't see plate tectonics as we do on Earth, Venus likely has an active surface
with volcanic activity.
Venus Interior
● Very similar to Earth's with core, mantle and crust
● Central iron- nickel like core and crust
● The surface of Venus also seems to have features similar to those seen on earth.
● There are 2 major highland regions - Ishtar Terra in the North and Aphrodite Terra
nearer the Equator of Venus.
● There are also mountain like structures - referred to as ‘Mons’
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Craters
❏There are roughly 900 craters visible on venus. This is not a particular large number, and
they tend to be concentrated in certain regions
❏When you compare this to mercury or the moon these are very small numbers
and they can be concentrated in certain regions if there are no plate tectonics
and bodies of water on the surface, then something is clearly resurfacing the
planet.
❏Most likely by some sort of volcanic activity
❏This is evidence that something must be resurfacing the face of this planet. Since there
is no water anywhere on the surface the most likely phenomenon to change the surface
is volcanic activity
❏The Nature of the craters is related to the surface conditions
❏Because of the thick atmosphere, objects need to be of a much larger size to reach the
surface without burning up - the smallest creatures we see are 3km across
❏Also the mall number of craters and other evidence suggests the surface is at most 1
billion years and possible as little as 500 million years old
❏Young surface
Venus crust
● Even Though venus seems to have a similar surface and interior,there are no plate
tectonics as we see on earth
● This may be the result of a crust that is either too thick to break into the plates
● If Venus otherwise is so similar to Earth, then why are there differences
○ There is also a theory that too thin a crist could cause this effect
■ Too thick to break into plates
■ Too thin then you would not get plate tectonics
■ Another Factor may be lack of water , as water also acts as a lubricant on
earth to help the plates move
■ Without the pressure of water it so hard for rock to move.
Document Summary
Venus has an interior that is likely very similar to earth"s. Although we don"t see plate tectonics as we do on earth, venus likely has an active surface with volcanic activity. Very similar to earth"s with core, mantle and crust. Central iron- nickel like core and crust. The surface of venus also seems to have features similar to those seen on earth. There are 2 major highland regions - ishtar terra in the north and aphrodite terra nearer the equator of venus. There are also mountain like structures - referred to as mons". There are roughly 900 craters visible on venus. This is not a particular large number, and they tend to be concentrated in certain regions. Most likely by some sort of volcanic activity. This is evidence that something must be resurfacing the face of this planet. Since there is no water anywhere on the surface the most likely phenomenon to change the surface is volcanic activity.
