Can we estimate the rate of deterioration of Mars' atmosphere?

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l3p3r

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<p>Hi all,</p><p>&nbsp;Suppose we were to pump up the Martian atmosphere to something nice like 0.5bar, what sort of time scale are we looking at for it to deteriorate again to 0.1bar (for example, assuming no more gasses are added in that time)?</p><p>Is there a relatively straightforward way of calculating such a thing based on strength of gravity / diameter / atmospheric composition and distance from the sun?&nbsp;</p><p>&nbsp;Also, will the mass of Earth's atmosphere decrease significantly over the next hundred million years (discounting other processes)? </p> <div class="Discussion_UserSignature"> </div>
 
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vogon13

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<p>What gas are you planning on using ??</p><p>&nbsp;</p><p>Hydrogen??&nbsp; Probably would blow off faster than you could ever hope to dump it on.</p><p>&nbsp;</p><p>Uranium hexafloride??&nbsp; Kinda pricey for a whole planet full, but would probably stick around a nice long time and stink up the place.</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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vogon13

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<p>Silylene did some good work on atmospheric retentivity looking at Iapetus on the old board.&nbsp; From temperature and mass, Iapetus is rather pokey about dissipating molecular nitrogen and methane. </p><p>&nbsp;</p><p>Mars is much more massive than Iapetus, but warmer too.&nbsp; CO2 would be a good place to start.&nbsp; Since it is a green house gas, if you dump enough and warm up the place a bit, all (or most) of the frozen stuff already there&nbsp; volatilizes and you get more gas for the buck.</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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baulten

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Hi all,&nbsp;Suppose we were to pump up the Martian atmosphere to something nice like 0.5bar, what sort of time scale are we looking at for it to deteriorate again to 0.1bar (for example, assuming no more gasses are added in that time)?Is there a relatively straightforward way of calculating such a thing based on strength of gravity / diameter / atmospheric composition and distance from the sun?&nbsp;&nbsp;Also, will the mass of Earth's atmosphere decrease significantly over the next hundred million years (discounting other processes)? <br /> Posted by l3p3r</DIV></p><p>It'd depend on the gas you use.&nbsp; Heavier gasses will last longer, as the sun/solar wind won't be able to heat them up and accelerate them passed escape velocity as quickly as light gasses.&nbsp;</p><p>Earth's atmosphere shouldn't decrease significantly for a long time, because of the magnetosphere. </p>
 
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keermalec

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<p>Its difficult to say how long it will take, but it IS possible to sasy how much longer it will take.</p><p>For example, given that Mars's escape velocity is 5 km/s, currently 1 in 4x10E91 CO2 molecules have a velocity equal to or greater than this. This is a very small number, which explains why Mars's atmosphere is not visibly shrinking.</p><p>If you add Hydrogen to Mars, 1 out of every 25,000 Hydrogen molecules will have a speed above escape velocity. Therefore Hydrogen will escape at a rate 10E87 times faster than CO2.</p><p>Water will go at a rate 10E53 times faster than CO2 and Oxygen at a rate 10E24 times faster.</p><p>As an indicator, Oxygen is lost from the Earth's atmpsphere at a rate 10E194 times slower than CO2 is lost on Mars.</p><p>Don't know if this helps...</p><p>&nbsp;</p><p><br /><br />&nbsp;</p> <div class="Discussion_UserSignature"> <p><em>“An error does not become a mistake until you refuse to correct it.” John F. Kennedy</em></p> </div>
 
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l3p3r

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Thanks for the replies everyone! I was thinking specifically about the case where the atmosphere is made suitable for humans to live on the surface... I expect we can get away with a much lower pressure than here on Earth... but if we could get it to such a state and then stop whatever processes we were using to increase the pressure / change the composition, then what rough time scale can we expect the atmosphere to remain hospitable. <div class="Discussion_UserSignature"> </div>
 
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