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Author Topic: How do the atmospheres of Mars and Earth differ?  (Read 3619 times)

Offline DAVID WOOD

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How do the atmospheres of Mars and Earth differ?
« on: 14/11/2011 11:57:28 »
I am not sure if this question has been asked yet but what is the difference between out atmosphere and that of mars? and what would be needed to get it close enough to ours that we could live there?
« Last Edit: 14/08/2012 09:43:12 by chris »


 

Offline CliffordK

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« Reply #1 on: 14/11/2011 18:44:49 »
Wikipedia has a good breakdown of the atmosphere of Mars.  The mix of gases is:

95% CO2, 2.7% Nitrogen, 1.6% Argon, 0.13% Oxygen.

If that was the only problem, then plants would be able to convert the CO2 to Oxygen. 

The biggest problem is that the atmospheric pressure varies, but is about 1 kilopascal at the surface, or about 1/100th of that on Earth.  I.E.  even if it was 100% oxygen, it would be too thin to breathe.

Rocks are generally oxides, so in theory, they could be converted to oxygen. 

The biggest, and probably insurmountable hurdle is the gravity on Mars which is about 1/3G.  I don't think there is enough gravity to hold a dense oxygen/nitrogen rich atmosphere...  or if one did have an atmosphere, there might be significant "leakage" into space which would mean that it would have to be continuously replenished which would be very bad.

Perhaps one could build a Krypton/Xenon atmosphere which would give pressure, but not breathable gasses, but finding that much heavy inert gases would probably mean mining Jupiter..  which would mean a lot of transport between planets.
 

Offline Nizzle

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« Reply #2 on: 15/11/2011 05:50:03 »
The biggest, and probably insurmountable hurdle is the gravity on Mars which is about 1/3G.  I don't think there is enough gravity to hold a dense oxygen/nitrogen rich atmosphere...  or if one did have an atmosphere, there might be significant "leakage" into space which would mean that it would have to be continuously replenished which would be very bad.

Perhaps one could build a Krypton/Xenon atmosphere which would give pressure, but not breathable gasses, but finding that much heavy inert gases would probably mean mining Jupiter..  which would mean a lot of transport between planets.


Your solution will not work.
First and foremost, even more important than the very low gravity, Mars lacks a Magnetosphere, so even Krypton/Xenon based atmospheres would just be blown off the surface into space by solar wind.
 

Offline CliffordK

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« Reply #3 on: 15/11/2011 07:05:35 »
[xx(]

Hmmm...
So, could one induce a magnetosphere on Mars?

Perhaps build a spiral DC electric grid  ;)

There has to be more to the atmosphere.  Venus has a dense atmosphere, but a weak magnetic field.

Why does Titan also have a dense atmosphere, yet the moon is smaller than Mars?
 

Offline Nizzle

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« Reply #4 on: 15/11/2011 07:10:00 »
Venus is one big volcano, so new atmosphere is created faster than solar wind can blow it away.
And for Titan, it's so much farther away from the sun that the solar wind is not a big factor over there. Certainly considering the fact that Titan can "hide" behind Jupiter for a part of the time. Something which Mars can't..

The fact that you mention that Titan also has a dense atmosphere, but lower gravity than Mars further disproves your own thought that gravity is most important for holding the atmosphere ;)
« Last Edit: 15/11/2011 07:12:05 by Nizzle »
 

Offline damocles

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« Reply #5 on: 16/11/2011 14:12:42 »
Venus is one big volcano, so new atmosphere is created faster than solar wind can blow it away.
And for Titan, it's so much farther away from the sun that the solar wind is not a big factor over there. Certainly considering the fact that Titan can "hide" behind Jupiter for a part of the time. Something which Mars can't..

The fact that you mention that Titan also has a dense atmosphere, but lower gravity than Mars further disproves your own thought that gravity is most important for holding the atmosphere ;)

Umm ...

Titan is a moon of Saturn, not of Jupiter. It is an outer moon, and its orbit is aligned at about 27 to the orbit of Saturn. Occasions when it can "hide" (behind Saturn and/or its ring system) are rarer, and of shorter duration than eclipses of our moon. But for the sort of "hide" that is needed in this case Titan is well enough off: apparently the magnetosphere of Saturn covers a huge amount of space, and effectively shields Titan most of the time.
 

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« Reply #5 on: 16/11/2011 14:12:42 »

 

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