Ancient Magnetic Fields On the Moon Could Be Protecting Precious Ice (science.org) 32
sciencehabit shares a report from Science.org: For years, scientists have believed frigid craters at the Moon's poles hold water ice, which would be both a scientific boon and a potential resource for human missions. Now, researchers have discovered (PDF) a reason why the ice has persisted on an otherwise bone-dry world: Some polar craters may be protected by ancient magnetic fields. Researchers have known about the anomalies ever since the Apollo 15 and 16 missions in 1971 and 1972, when astronauts measured regions of unusual magnetic strength on the surface. Some anomalies are now known to be up to hundreds of kilometers across. Although their origin is debated, one possibility is they were created more than 4 billion years ago when the Moon had a magnetic field and iron-rich asteroids crashed into its surface. The resultant molten material may have been permanently magnetized.
Thousands of the anomalies are thought to exist across the lunar surface, but the team mapped ones at the south pole in detail using data from Japan's Kaguya spacecraft, which orbited the Moon from 2007 to 2009. They found at least two permanently shadowed craters that were overlapped by these anomalies, the Sverdrup and Shoemaker craters, and there are likely more. Although the remnant fields are thousands of times weaker than Earth's, they could be sufficient to deflect the solar wind. Craters with known anomalies could become prime targets for science and exploration. NASA is already planning to visit the south polar region with a rover due for launch next year, called VIPER, and the agency intends to send humans there later this decade as part of its Artemis program. Studying the ice could reveal how it was delivered, which may in turn shed light on how Earth got its water.
Thousands of the anomalies are thought to exist across the lunar surface, but the team mapped ones at the south pole in detail using data from Japan's Kaguya spacecraft, which orbited the Moon from 2007 to 2009. They found at least two permanently shadowed craters that were overlapped by these anomalies, the Sverdrup and Shoemaker craters, and there are likely more. Although the remnant fields are thousands of times weaker than Earth's, they could be sufficient to deflect the solar wind. Craters with known anomalies could become prime targets for science and exploration. NASA is already planning to visit the south polar region with a rover due for launch next year, called VIPER, and the agency intends to send humans there later this decade as part of its Artemis program. Studying the ice could reveal how it was delivered, which may in turn shed light on how Earth got its water.
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How's that funny enough to spend mod points on? I mean, even by immature ten-year-old standards that's a lame joke.
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Unless you exclude ACs from the human race. Which is certainly a position you could argue, even if it doesn't win a popularity contest.
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Studying the ice could reveal how it was delivered, which may in turn shed light on how Earth got its water.
So is the source of Earth's water particularly mysterious then? Earth's got lots of chemicals of all kinds. Is it the presence of enough oxygen to form water that's unexpected? Hydrogen is obviously really common and reacting it with any oxygen to make water doesn't seem that surprising. Or is there reason to suppose the water isn't 'home grown'?
It's not just the fact there is water, it's the quantity. There's much more water on earth than other similar places (e.g. Venus) and than is expected by current models of Earth's formation. If the water all came at the time Earth was formed and stayed here, you'd expect it to be more evenly distributed.
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Venus is closer to the sun than Earth, and has extremely low rotation. It also has a much weaker magnetic field than Earth. Currently it's hot enough to melt lead on the surface, as well, but that's partly due to atmospheric conditions, so we can't say it's always been that way. In any case, it's different enough from Earth that I don't think that it should be that much of a mystery that there's less water than Earth, even if we can't pin down an exact model. Mars, which is really the only other candidate t
Re: Mysteries (Score:2)
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Yes. There's lots of oxygen, but we think the majority of the hydrogen was blown away from the inner planets during the formation of the solar system. The current thinking is that the water we have now was delivered to the inner planets (and the moon) during the subsequent bombardment.
Fixed that for you - (Score:1)
and a potential non-renewable resource for human missions
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and a potential non-renewable resource for human missions
Depends on how we use it. Where we make it into rocket fuel, I suppose some could leave the planet. Most of it used to keep humans alive will probably be very heavily recycled because it will probably be much easier than collecting new water. After all, water would most likely either need to be mined in solid form, or wells would need to be dug and heated to collect liquid water for a while and then probably need to be re-bored in a new location after a month or so to get water. Another possibility is to ge
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How does that differ from "building a habitat"?
Also, we know that the human body does not react well to long periods in microgravity ("zero gravity"). We do not know, yet, how well the human body reacts to long periods under 1/6th of a g. Probably a good idea to get a good handle on that, before planning to build a Lunar base.
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Probably a good idea to get a good handle on that, before planning to build a Lunar base.
Before building a lunar city, certainly. I think a lunar base would be a pretty good place to find out whether humans deteriorate at 1/6th G. Either that or in a spinning space habitat. After all, we're not going to ever know if we don't try. Personally I think it's likely that lower gravity will make little difference (as long as there's a good exercise program and people wear body weights and so forth since muscle atrophy could still be a concern) until you get quite close to 0 G. That's speculation until
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Where you can change the spin rate - and therefore the pseudo-gravity - pretty much at will.
Why transparent? Oh, yeah, very SF pretty. Very easy for radiation to get through. Probably relatively low strength (compared to the same kg/sq.m of your best non-transparent materials ; otherwise we'd have see-through nuclear reactors and no worry about hidden cracks). That's
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Where you can change the spin rate - and therefore the pseudo-gravity - pretty much at will.
That is really useful for testing at different levels of "gravity". It depends a bit on what you want to test though. If you also want to test out landing on planetary bodies, construction on those bodies, in situ resource usage, etc. then an initial moon base makes sense.
Why transparent? Oh, yeah, very SF pretty. Very easy for radiation to get through. Probably relatively low strength (compared to the same kg/sq.m of your best non-transparent materials ; otherwise we'd have see-through nuclear reactors and no worry about hidden cracks). That's a design choice that will have to be strongly justified. (I see later you yourself ask "Then you have to decide if you need a transparent dome, or opaque." ; yes, it's a very big question.)
"Windows"? Pretty views? Shrug. Make windows, with seals and protective airlocks (protective for everywhere else). All your instrumentation is going to be non-naked eye, so looking out of the window doesn't have a technical justification I can see. Having worked for years in remote, frequently hostile environments, you'd find that most of the windows are blacked out - so the night shift person in your cabin can sleep through the day.
Well, in SF, it's mainly for the look. There are some practical possible reasons though. The context from the first comment on this was terraforming. Among other things, that means growing plants, which means you need a lot of light, and d
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Agreed. The 1970s "O'Neill" designs proposed them as a solution for the "lighting the crops" - but frankly that with 1970s era PV and LED efficiency. O'Neill had to add radiation shielding, or mirrors to bring the light inside the rest of the radiation shielding, to the later versions.
Generally, no disagreement. But I think that you're including an awful lot of thermal energy in that budget, along wi
Wtf "ancient" (Score:1)
A magnetic field either is or isn't. It's hardly something that just appears out of nowhere and noone (to my knowledge) has been there to install electromagnets.
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So, it's completely impossible that a magnetic field could be create by currents of molten rock moving? For example, melted rock after some asteroid strike?
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A magnetic field either is or isn't. It's hardly something that just appears out of nowhere and noone (to my knowledge) has been there to install electromagnets.
Ancient magnetic field because it isn't being created dynamically by a spinning iron core like ours on Earth is. The source of the magnetism is ancient.
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Most (all) of the Moon's core is above it's Curie temperature (there's some question over whether there is a sufficiently distinct core to call such). The expressed surface fields are from aligned magnetite, haematite, and titanite crystals in the mantle and crust, left over from when there was a working dynamo - several billion years ago.
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I'd hesitate to go that far ("moron" being a technical diagnosis, if nothing else), but I have a mental "yellow flag" on things he says or claims. Very much one of nature's ^H^H^H^H^H his education's "speak first and think seventh" people.
I'm not certain that a Curie point above the "melting point" is absolutely impossible, but I have to think in terms of multi-component melts and some of the solid phases having different magnetic properties to the melt. But hey - geologist, here ;
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one thing's for sure... (Score:2)
Why isn't the first post here... (Score:2)
about TMA-1 [wikipedia.org]?
Is this site News for Nerds or not?
The First Born (Score:2)
of Slashdot old enough to remember this are passing away?
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