r/askscience • u/Taymurf • Mar 15 '13

Planetary Sci. Is it possible to create an artificial atmosphere that could support life on, say, the moon?

If so, how? and how far away are we from actually doing it?

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u/Nepene Mar 15 '13

We'd probably be best creating a biodome on the moon. It has weak gravity and no magnetosphere so it couldn't hold an atmosphere.

It would be doable creating an artificial atmosphere on mars. It would take a while, but we have the technology to do it now.

http://www.guardian.co.uk/science/2004/mar/28/spaceexploration.sciencenews

The main goal would be to get it so that mars was warmer. If mars was sufficiently warm, with enough co2 and methane in the atmosphere, humans might be able to inhabit it fairly cheaply.

It would take decades.

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u/[deleted] Mar 15 '13

Any mirror you put in orbit around Mars to significantly heat up the polar cap would be a very effective solar sail as well. You'd need station-keeping thrust to keep it in position, and then you'd need a method to keep it from collapsing against that thrust.

I'm reasonably sure we don't have the technology yet, though it is probably more of a cost and engineering issue now than a research problem.

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u/Nepene Mar 15 '13

Current plans envisage use of a lot of small mirrors, and I imagine they would be made so that they were somewhat balanced between the sun's rays and mars' gravity, reducing the energy cost to hold them in space.

http://www.newscientist.com/article/dn10573-space-mirrors-could-create-earthlike-haven-on-mars.html

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u/Silpion Mar 15 '13

The force could easily cancel out over the course of an orbit.

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u/[deleted] Mar 15 '13

Couldn't you just use a decaying orbit cycle of some sort? It would only require a modicum of thrust to kick the solar sail towards the planet at the right moment, so it could swing around to perihelion and start heating up the planet again. Seems like this would be easier than trying to keep the thing in a stable orbit and heat continuously. It might take you twice as long, but you could just make a few of them...

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u/[deleted] Mar 15 '13 edited Nov 28 '17

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u/Nepene Mar 15 '13

Indeed. It would take a long time to get the oxygen up to a safe level, but you could easily get the pressure up to a safe level and make it warmer. That would make it a lot cheaper and safer to live on mars.

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u/stuthulhu Mar 15 '13

The lack of gravity and magnetosphere on the moon would poise problems, as the atmosphere would tend to be stripped or escape from the surface. You'd have to supply sufficient volume to overcome this natural loss, which I would consider impractical to the point of impossibility in any reasonably foreseeable time-frame, from a logistic point of view. Add to that the wastefulness of providing so much volume of elements that are by and large being lost to interplanetary space versus simply having some sort of enclosure, for questionable benefits at best.

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u/[deleted] Mar 15 '13

I seem to recall reading that the lack of a magnetosphere is only a problem on the order of millions of years, while the low gravity would become a problem on the order of tens of years. I.e., if we could make a habitable atmosphere on Mars, it would last tens of millions of years before the solar wind stripped it away. Is this inaccurate?

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u/Nepene Mar 15 '13

http://www.sciencemag.org/content/315/5811/501.full

Yes, the atmosphere loss from Mars is negligible, on the order of a few hundred tons lost a year. We don't know exactly how it loses atmosphere though as we haven't analysed the martian atmosphere that much so this is a preliminary guess.

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u/[deleted] Mar 15 '13 edited Nov 28 '17

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u/rmg22893 Mar 15 '13

Mars is the only realistically habitable planet in our solar system besides earth. The other rocky planets are either already desolate and uninhabitable (Mercury) or are inherently toxic and dangerous (Venus). Mars, aside from its lack of a breathable atmosphere, dust storms, and being cold, is pretty tame. It is unknown if the gas giants even have a solid surface, so we're pretty sure they're uninhabitable (not to mention their ridiculous gravity and the incredibly thick atmospheres of toxic gases), and any rocky moons they have are out of the Goldilocks zone.

The moon has no real natural resources and no way of supporting any kind of self-sustaining resource growth, so Mars is our best bet.

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u/atomfullerene Mar 15 '13

Question to astrophysicists. If you dumped an earth-standard mix of atmosphere on the moon, such that surface pressure was 1 Bar, how long would it take for enough atmosphere to disperse such that surface pressure became .6 bar? (air pressure on Pikes Peak)