RE: New Images Of Pluto From 7,750 Miles
July 22, 2015 at 2:40 pm
(This post was last modified: July 22, 2015 at 2:51 pm by Anomalocaris.)
Latest batch of images show the region named Cthulhu is heavily cratered. So Pluto did not lack for craters because it somehow evaded planetoids bombardment in its history.
Visually the crater density there appear not as high as on lunar highland, so either Pluto was never subjected to the late heavy bombardment the inner planets suffered around 3.9 billion years ago, or the cratered terraen is almost that old, but not quite that old.
Either way, there appear to be major regional variations in the age of Pluto's surface, which suggest on ongoing geological activity.
One intriguing hypothesis I heard regarding how Pluto could have retained an atmosphere even though its weak gravity can't prevent atmospheric gases from escaping into space at a prodigious rate is the surface of Pluto has enough nitrogen ice on its surface that nitrogen gas sublimating from the ice balances nitrogen gas escaping into space. But it is estimated Pluto would have had to lose a layer of nitrogen ice 10 miles thick from its entire surface over the life of solar system to maintain its current atmosphere over that period. So the presence of heavily cratered terraen at least 3 billion years old cast doubt on the nitrogen ice surface theory. Craters made 3 billion years ago should have sublimated into oblivion a long time ago.
Visually the crater density there appear not as high as on lunar highland, so either Pluto was never subjected to the late heavy bombardment the inner planets suffered around 3.9 billion years ago, or the cratered terraen is almost that old, but not quite that old.
Either way, there appear to be major regional variations in the age of Pluto's surface, which suggest on ongoing geological activity.
One intriguing hypothesis I heard regarding how Pluto could have retained an atmosphere even though its weak gravity can't prevent atmospheric gases from escaping into space at a prodigious rate is the surface of Pluto has enough nitrogen ice on its surface that nitrogen gas sublimating from the ice balances nitrogen gas escaping into space. But it is estimated Pluto would have had to lose a layer of nitrogen ice 10 miles thick from its entire surface over the life of solar system to maintain its current atmosphere over that period. So the presence of heavily cratered terraen at least 3 billion years old cast doubt on the nitrogen ice surface theory. Craters made 3 billion years ago should have sublimated into oblivion a long time ago.
