Posted on 04/19/2018 3:07:59 PM PDT by Voption
“The movie “Mission to Mars” sort of explains this as the reason Mars went dead, although it was most likely just the loss of its magnetic field.”
Went dead?
Mars once had earth-like conditions with water and an atmosphere. At some point, however, the atmosphere escaped into space and the water froze. They think it’s because the core of Mars solidified, causing its magnetic field to fail, and the solar wind did the rest. But it was also hit by a big asteroid. The Hellas impact basin is the 2nd largest in the solar system.
The loss of Mars’ atmosphere was probably multifactorial, including the fact that Mars has a lot less mass than Earth, and therefore the escape velocity of atmospheric gases is less. It’s actually very interesting. Look up Atmospheric escape.
Yes, there’s debate on how massive a planet has to be to retain an atmosphere. Factors are surface gravity, magnetic field, solar wind, even temperature and spin. Very complex. But look at Titan—it has a mass less than a quarter of Mars, but an atmosphere thicker than Earth’s. Relevant factor: only 2.5% the solar wind Mars gets.
Thanks for the details. That’s really interesting (the mass of Titan). To me, this complexity is why being dogmatic about the factors that define Earth’s climate is ridiculous.
Got it. Thanks.
It’s always been ridiculous. The ones who accept AGW blindly are either pushing an agenda and/or don’t know much about it. You can’t make absolute predictions about a system when you don’t know all the variables.
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