Author Topic: This is huge: *current* liquid water on Mars.  (Read 2827 times)

Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #90 on: August 09, 2018, 10:05:45 AM »
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Mars needs a larger iron core and more mass.
Pretty much.  A project for the next few millennia just might be not only adding a few nickel-iron asteroids to Mars' core, but melting it and starting up the planetary dynamo again.

And then we get to watch what happens when plate tectonics re-start!
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Re: This is huge: *current* liquid water on Mars.
« Reply #91 on: August 09, 2018, 10:11:25 AM »
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That's actually not a bad guess — you're within a few orders of magnitude, and it would be a sensible safety margin with regard to planning atmospheric maintenance.  When Mars' magnetic field collapsed and the solar wind was able to reach the Martian atmosphere, it still took millions of years to blow it away, and that was about 3.7 billion years ago when the sun was much younger and more active.  It's currently losing its atmosphere at the rate of 100 g/s... but it has 2.5x1019 g of atmosphere left, even at its low pressure, so it's not like it's wisping away at an alarming rate.
Send the robots out every century or so to wrangle small chunks of air-bearing rock. Just do the math to keep ahead of the loss. OR park some big ones around Mars and "siphon" them.
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
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Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #92 on: August 09, 2018, 10:29:57 AM »
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Send the robots out every century or so to wrangle small chunks of air-bearing rock. Just do the math to keep ahead of the loss. OR park some big ones around Mars and "siphon" them.
Exactly that.  Once an atmosphere is in place, it becomes a matter of maintenance, and only periodic maintenance at that.

Well, "only" in the sense that comets need to be coaxed out of their orbits and brought to Mars and then melted, filtered, and installed into the ocean(s).  Probably going to need to leave some extra at the poles for functioning ice caps.  Anything left over can be hydrolyzed into oxygen and fusion fuel.  This is a project for the end of this millennium, not the end of this century.
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #93 on: August 09, 2018, 10:46:58 AM »
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I wonder how much mass could be added to Mars without disrupting it's orbital motion?
I missed this question earlier, but it's a good one.  The answer is: lots.  Its orbital period would speed up a little, but only to the extent of making the year a few seconds shorter.  That's because the difference between the mass of the orbiting object (Mars) and the mass of the orbited object (the Sun) is so vast.  The Sun's mass completely dominates the interaction.
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Re: This is huge: *current* liquid water on Mars.
« Reply #94 on: August 09, 2018, 11:21:18 AM »
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Exactly that.  Once an atmosphere is in place, it becomes a matter of maintenance, and only periodic maintenance at that.

Well, "only" in the sense that comets need to be coaxed out of their orbits and brought to Mars and then melted, filtered, and installed into the ocean(s).  Probably going to need to leave some extra at the poles for functioning ice caps.  Anything left over can be hydrolyzed into oxygen and fusion fuel.  This is a project for the end of this millennium, not the end of this century.
One method of diverting a threatening asteroid would be the gravity tractor, a small mass parked near a large one in such a position to cause the asteroid to change directions. A small tug very far away would do. One the target item is on the right path the "tug" moves to the next one on the list. The variables would be known with practice and a single tug would be constantly sending rocks to Mars. We might choose to have them impact in such a way as to heat the atmosphere a bit with every impact. And it might not be a bad idea to make the impacts happen on the other side of the planet from the initial settlements. Half a planet is a lot of room.
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

Offline Baruch

Re: This is huge: *current* liquid water on Mars.
« Reply #95 on: August 09, 2018, 12:55:57 PM »
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Mars needs a larger iron core and more mass.

Nobody needs more Catholicism ;-)
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Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #96 on: August 09, 2018, 04:37:39 PM »
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One method of diverting a threatening asteroid would be the gravity tractor, a small mass parked near a large one in such a position to cause the asteroid to change directions. A small tug very far away would do. One the target item is on the right path the "tug" moves to the next one on the list. The variables would be known with practice and a single tug would be constantly sending rocks to Mars. We might choose to have them impact in such a way as to heat the atmosphere a bit with every impact. And it might not be a bad idea to make the impacts happen on the other side of the planet from the initial settlements. Half a planet is a lot of room.
I'm not sure that impacting on the surface of a much smaller planet than the Earth with an artificially maintained environment (or, more fragile, one being constructed) is a good idea.  I'd much rather see them just diverted into safer orbits.  Now, a water-bearing comet or centaur or plutino, sure, I can see landing that, but I'd like to see the delta-v relative to the surface reduced to damn near zero before letting it fall in, and dropped from as low an altitude as possible.

I am also irresistibly reminded of Mitchell Burnside Clapp's You are not allowed to view links. Register or Login...
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Re: This is huge: *current* liquid water on Mars.
« Reply #97 on: August 09, 2018, 04:45:34 PM »
I used to preface my speculative comments with "assume all parties involved are competent."  Nobody ever read that bit, I think.
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #98 on: August 09, 2018, 05:03:39 PM »
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I used to preface my speculative comments with "assume all parties involved are competent."  Nobody ever read that bit, I think.
Even with competence assumed, I can't say I'm a big fan of dropping rocks on planetary surfaces, even for the best of reasons.
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Re: This is huge: *current* liquid water on Mars.
« Reply #99 on: August 09, 2018, 06:10:19 PM »
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Even with competence assumed, I can't say I'm a big fan of dropping rocks on planetary surfaces, even for the best of reasons.
What problems do you have with that I proposed?
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

Offline Baruch

Re: This is huge: *current* liquid water on Mars.
« Reply #100 on: August 09, 2018, 07:08:12 PM »
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Even with competence assumed, I can't say I'm a big fan of dropping rocks on planetary surfaces, even for the best of reasons.

Ultimate WMD.  Asteroid pool.  Human colony ... in the side pocket.
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Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #101 on: August 10, 2018, 12:48:06 AM »
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What problems do you have with that I proposed?
I don't see the point of deliberately driving it into Mars' surface, especially if there's a colony there.  If you want it for the resources, just tug it into orbit and mine it from there.  If you want to alter its orbit to prevent it from being an impact risk, send it into Jupiter or the Sun.  If you want ices, you want a comet, centaur or plutino, not an asteroid.
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Re: This is huge: *current* liquid water on Mars.
« Reply #102 on: August 10, 2018, 05:04:38 AM »
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I don't see the point of deliberately driving it into Mars' surface, especially if there's a colony there.  If you want it for the resources, just tug it into orbit and mine it from there.  If you want to alter its orbit to prevent it from being an impact risk, send it into Jupiter or the Sun.  If you want ices, you want a comet, centaur or plutino, not an asteroid.
As pointed out earlier in this thread, the incoming would be aimed at the uninhabited side of Mars, probably opposite Valles Marineris. The impact not only releases the water, it also adds a bit of heat to the atmosphere. I'm not suggesting willy-nilly bombardment of the planet, not with people on it.

We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

Offline trdsf

Re: This is huge: *current* liquid water on Mars.
« Reply #103 on: August 10, 2018, 11:25:47 AM »
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As pointed out earlier in this thread, the incoming would be aimed at the uninhabited side of Mars, probably opposite Valles Marineris. The impact not only releases the water, it also adds a bit of heat to the atmosphere. I'm not suggesting willy-nilly bombardment of the planet, not with people on it.
Ah, okay, I was confused by your use of 'asteroid'.  To the best of current knowledge, they haven't useful water content -- although it does appear Ceres has ice.  That one's too big to manage, though; comets remain our best resource.  That's not without its own problems: comets move really fast, even by planetary dynamics standards.  Centaurs are the next best bet, but they're way out hanging around Uranus and Neptune.  Plutinos  and other Kuiper Belt icy bodies are even further — it took nine years for New Horizons to get from here to Pluto, and that's the near one.  Speaking of, New Horizon's flyby of 2014 MU69 is coming up fast -- Jan 1, 2019.

If our understanding of asteroid composition changes and most of them are icy, that's different, of course.  :)

It's worth adding that there's reason to think that You are not allowed to view links. Register or Login, frozen solid across a stretch of the northern hemisphere.  And the Phoenix lander provided evidence for Martian permafrost.  It's hard to say how much water is already there, but there may be quite a bit.
Sir Terry Pratchett, on being told about the theory that the universe is a computer simulation: "If we all get out and in again, would it start to work properly this time?"

Re: This is huge: *current* liquid water on Mars.
« Reply #104 on: August 10, 2018, 01:21:56 PM »
Sorry, just a lump term. Anything beyond Mars that could be useful.

And comets might have the most ice, but as you say, it's currently out of reach. The pushers I spoke of could be guided by a cell phone.

ETA: Remember that the rings of Saturn are made of mostly ice. Enough to make a planet the size of Mars, I think.
« Last Edit: August 10, 2018, 01:25:26 PM by Gawdzilla Sama »
We 'new atheists' have a reputation for being militant, but make no mistake  we didn't start this war. If you want to place blame put it on the the religious zealots who have been poisoning the minds of the  young for a long long time."
PZ Myers

 

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