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I thought our hot core was due to radionuclide decay? |
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Also besides, a moon won't help Mars hold on to an
atmosphere, as far as I know. I thought it was a question of
gravity - or am I missing something? |
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With a stronger magnetic field, less radiation would reach the surface but it would make little difference to the atmosphere. |
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Well Max, If Mars' gravity is too weak to hold an atmosphere, then why even bother thinking about terra-forming it? All those scientists better start posting their resumes on monster. |
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Why not a massive UV-filtered glass ceiling with oxygen and nitrogen underneath it? |
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I think crashing a few comets into it would temporarily give it a thicker atmosphere, and it could be that "temporarily" in this case might mean longer than there are likely to be humans, so it might be OK. Also, i can imagine water vapour being zonked into oxygen and hydrogen by the radiation and the hydrogen leaving the atmosphere faster than the oxygen would help. |
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Yes, less radiation is good and yes, Mars won't hold an
atmosphere unless it's replenished, but losses are slow. The
main point is that your main premise, on which the idea was
based, is wrong. |
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Definitely agree with you there, [MB], but were it Vesta in an unstable orbit it might end up giving Mars an atmosphere by colliding with it and subliming. |
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[MB] Apparently there isa theory that the incomplete magnetic field does accelerate atmosphere loss (see link). Since the moon isn't responsible for generating magnetic fields, though, the idea still doesn't help. |
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How much of an atmosphere could Mars more-or-less hold onto ? It'd have to be 3x's the depth of Earth's in order to get the same pressure (seeing as gravity is 1/3) |
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I think if you were going to move a significant portion of Mars' weight in asteroids from the asteroid belt, you might as well just move Mars into an Earth-orbit LaGrange point. |
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It seems that [tgu] is saying that with tidal forces of sufficient strength, Mars could also have a molten iron core, over time. For some inexplicable reason this would give Mars a decent magnetic field that would prevent solar winds driving off an atmosphere of any kind. |
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Last time I checked the curie temp of iron was 1043K, a tad bit cooler than a molten iron core, so we going to have to spin the planet a wee bit faster on top of its new moon. Easy, just send the moon around faster (just below escape velocity), it will drag the planet along with it, ooops there it goes. I think we have lost several moons the same way, and now we are only left with seven....not to mention just how much that fusion reactor at the core does for our well-being... |
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I thought this was an idea to expose bottoms to Mars. |
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Is Mars currently visible in our night sky? I, for one, am willing to contribute. (link) |
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So... let's just re-route Halley's comet to intercept Mars sometime here before it dissipates and it will ... well it won't do a whole lot, but let's do it anyway. |
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It will be good target practice. |
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Larry Niven, the science fiction writer, several times stated that our moon skims off our atmosphere, making and keeping it thin, instead of dense like Venus has. |
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Yes, as in Mount Lookitthat, but that was one of the aspects of his writing which i always found unconvincing. He also describes the solid surface of Venus as a "searing black calm" when in fact it glows in the dark and has plenty of daylight, so it's more of a searing orange calm. |
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Also, Venus lacks a magnetic field. |
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There would supposedly need to be a partial pressure of about a sixth of a bar of oxygen to enable people to breathe, but does that depend on gravity per se? What i mean is, is a sixth of a bar necessary or is that more an expression of the minimum concentration of oxygen? A column of gas weighing around a hundred and seventy grammes on Earth would way only sixty-five on Mars and still have the same concentration, and that's only about a dozen times the current mean surface pressure on Mars. |
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I think a big moon probably is helpful in sparking off life, but we've already done that part here on Earth. The next bit is to try and spread life around from its birthplace out into other parts of the solar system - at least for now anyway. |
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So Mars would tend to be a good candidate, it's reasonably close, has a temperature range that's not totally inhospitable, and is suspected to have some sub-surface ice that could be tapped to form a water-supply. |
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However, today it has no atmoshpere, and despite evidence of it existing in the past, no surface water. I've heard a theory that suggests that the solar wind, if not deflected appropriately into the poles by a magnetic field, can strip an atmosphere of its top-most levels, such as ozone, which would make life harder to exist out in the open. But the larger problem remains the formation of a viable atmosphere. |
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If we could generate the amounts of gasses required to repopulate all of Mars' atmosphere, we'd be able to solve the relatively measly issue of the very slight change in the proportions of the gasseous coctail that's suggested to be responsible for global warming in a snap. Carbon Dioxide forms 0.0387% of the Earth's atmosphere, and this is after a 36% increase from measured levels in 1750 (thanks Wikipedia) So if we find it tricky adjusting for a 36% rise to an overall concentration of 0.0387%, how tricky is it going to be to generate, from scratch, the other 99.8613% in order to sort out an atmosphere? |
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OK, so Mars is smaller, and maybe we don't need an atmosphere quite so good as the one we have on earth, so let's say we only need 20% of the Earth's atmosphere - it's still a couple of orders of magnitude beyond our current global capability. |
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So the job is a pretty big one. |
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That said, there's nothing there right now, so any microorganism that could get a foothold on the surface of Mars and exploit what is there, without any competition, should be able to grow exponentially. Were such an organism to produce a useful gas as byproduct to its growth, then we might be able to pave the way for a secondary form of life in, maybe, well I don't know how long. |
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The Earth's total atmosphere weighs 5×10^20 g (again, thanks Wikipedia) - so say one photosynthesising amoeba, weighing 1x10^-8g, and living for 100 days, that expells its body-weight in Oxygen each day, and also divides into two each day. On day 2, you have 2 amoebas, and on day 3, you have 4 etc, on the 100th day, you will have 6.338x10^29 amoebas, which between them will have generated 1.267x10^20g of Oxygen, which is plenty. Just nobody light a match. |
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Of course, it's unlikely that their growth-rate could sustain an unlimited doubling each day, there's practical limitations on how fast an amoeba can move, and whether available resources would allow the ones in the middle to double at a rate as quickly as the ones out on the edges, and loads of other things like that - but, it is interesting that if suitable life could be introduced to a barren planet, without the normal restrictions imposed by *other life* to hold it back, it could take off pretty quickly. |
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All we need is some non-air breathing bacteria that can exist and grow on bare rock, exposed to the unfiltered glare of the solar-wind, under sub-zero temperature conditions. Solve that problem and you've got the issue wrapped up. |
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Extremophiles is what you need, z_t. |
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The Martian atmosphere only needs to cover an area less than a third that of ours and it only needs to have a sixth of the pressure, though its scale height would be greater. It's also unclear how much it would matter that the atmosphere would be steadily lost because losing, say, one percent over a million years is very fast by cosmic standards but irrelevant by ours because something could be done to alleviate that long before then even if we're still around, such as the gradual electrolytic release of oxygen from Martian rocks. |
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The main reason for a magnetosphere, to my mind, is that it generates the Van Allen belts. |
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If everyone who visits Mars brings a balloon... |
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An atmosphere of pure oxygen sounds a trifle hazardous, even at 1/6th bar. |
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Would it? Surely 1/6th bar pure oxygen would be
less conflagragenic than our 20% oxygen
atmosphere? |
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Or maybe not - I can see how I might be wrong,
and would welcome enlightenment. |
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Incidentally, instead of giving Mars a moon, why
not make Mars into Earth's second moon? It would
be more convenient for commuting, for starters.
And if the distances are worked out properly (in
Imperial units, that is), Mars would gain some sort
of benefit, or at least tides to shift around
whatever water we can get there. |
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Nope. Partial pressure of oxygen is important for the basic combustion reaction, but the nitrogen (etc, but mostly nitrogen) in our air absorbs heat and removes it from the reaction, tending to suppress the flame. That is, stuff burns more readily in the equivalent pure-oxygen atmosphere, because it doesn't have to deal with the nitrogen (etc) acting as a heatsink. |
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Yep, that makes sense - thanks. |
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I learn something new every day. On the other
hand, being buried knowing only 29,200 facts is
probably not that impressive. |
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Hmm, you want to give Mars a magnetic field to help stop
solar
winds assisting in stripping it's atmosphere so fast? maybe
the better answer is to make it a moon rather
than
give it one. |
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Saturn has a nice big magnetosphere, but it's a bit
far out, Mars would get even less sun than it does,
which isn't good if you want a tan. |
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So move Saturn into Mars
orbit then slip Mars into orbit around it nice & snug inside
it's
magnetosphere. |
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Should get plenty of tidal
action from that too, just think of the surfing once we get
some
water on it. |
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[Reads the rest of the annos] |
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Huh! [Max] already went there (make it a moon rather than
give it one). |
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