Southern Arizona Hang Glider Association
Dust devils have been reported on Mars for years- but this is the 1st cool photo of one.
With the reduced air density and reduced gravity... somebody design me a hang glider for that place!
http://www.huffingtonpost.com/2012/03/0 ... ef=science
Photo of Dust Devil... on Mars
Moderators:ioan, John Wolfe, aaroncromer, jlowery
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Eric Tucker
Okay so let's see...
The lower gravity would decrease thermal intensity since it's gravity that's partly responsible for thermals to begin with.
The thinner air means that solar heating of the surface would be increased although this would be mitigated by it's increased distance from the sun.
The thin air would require a very fast glide although this would be somewhat mitigated by the decreased gravity.
The cold air would tend to increase thermal potential due to there being a greater temperature gradient at the surface, similar to what we see on earth when a cold front passes through. Increased temperature gradient would cause increased conduction from the land to the air above it although it's hard to say how that temperature gradient would extend into the atmosphere. The thinness of the air would mean a much longer mean free path that the air molecules would travel before colliding with another molecule. Hard to say how this would affect the temperature gradient through the atmosphere but since there's little pressure, there would be little to hold the surface air in place for long allowing for little time for it to heat to become very strong before releasing.
In any case, thermals would have to move very fast in order to get much out of them since the air is so thin, even with the decreased gravity.
So there are many competing factors in determining how strong and big thermals would tend to be. Dust devils are proof that there are thermals but even the strongest ones may be too weak to soar due to the low air density.
The bottom line:
It's likely you'll need a very big and slow glider. So just remember that the next time you go to Mars....and don't forget to bundle up and take lots of pictures for us.
Tucker
The lower gravity would decrease thermal intensity since it's gravity that's partly responsible for thermals to begin with.
The thinner air means that solar heating of the surface would be increased although this would be mitigated by it's increased distance from the sun.
The thin air would require a very fast glide although this would be somewhat mitigated by the decreased gravity.
The cold air would tend to increase thermal potential due to there being a greater temperature gradient at the surface, similar to what we see on earth when a cold front passes through. Increased temperature gradient would cause increased conduction from the land to the air above it although it's hard to say how that temperature gradient would extend into the atmosphere. The thinness of the air would mean a much longer mean free path that the air molecules would travel before colliding with another molecule. Hard to say how this would affect the temperature gradient through the atmosphere but since there's little pressure, there would be little to hold the surface air in place for long allowing for little time for it to heat to become very strong before releasing.
In any case, thermals would have to move very fast in order to get much out of them since the air is so thin, even with the decreased gravity.
So there are many competing factors in determining how strong and big thermals would tend to be. Dust devils are proof that there are thermals but even the strongest ones may be too weak to soar due to the low air density.
The bottom line:
It's likely you'll need a very big and slow glider. So just remember that the next time you go to Mars....and don't forget to bundle up and take lots of pictures for us.
Tucker
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Eric Tucker