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Mars NASA Earth Science Technology

NASA Proposes a Magnetic Shield To Protect Mars' Atmosphere (phys.org) 211

New submitter Baron_Yam writes: Apparently it is no longer necessarily science fiction to consider terraforming the red planet in a human lifetime. NASA scientists have proposed putting a magnetic shield at the Mars L1 Lagrange Point, diverting sufficient solar wind in hopes that the Martian atmosphere would thicken and heat the planet to the point of melting the ice caps, causing what remains of Martian water to pool on the surface. While not enough of a change to allow walking around without a space suit, this would make human exploration of the planet a much easier task.
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NASA Proposes a Magnetic Shield To Protect Mars' Atmosphere

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  • No real information (Score:2, Informative)

    by Anonymous Coward

    They don't mention much about how this magical magnetic barrier is going to be generated or powered. They also don't really know how long it will take a habitable atmosphere to form assuming it works at all, or what happens to everything if the shield fails at a later date and what kind of upkeep it would require. It sounds a lot like wishful thinking and hand-waving.

    • by jandersen ( 462034 ) on Tuesday March 07, 2017 @04:59AM (#53990923)

      It sounds a lot like wishful thinking and hand-waving.

      It probably is, at that. In my (limited) experience, phys.org tends to publish stories rich in big, glossy pictures, slightly sensationalising headlines and with a rather too "popular" (read: dumbed down) style. Maybe I'm being unfair, but I don't think their stories tend to qualify as real news, when most of it is a glossy writeup of things I have already seen elsewhere, on general news media like the BBC.

      I think this is a fundamental problem when popularising science news - when you look at the totality of science, and especially the amazing discoveries made in the first half of the 20th century, it really is quite mind-blowing, but unfortunately this does not reflect the day-to-day reality of most science. Which is why most attempts at making science news popular and exciting are doomed to be disappointing.

      As for the actual idea - I think it is well-established that a magnetic shield would be just the thing to protect the atmosphere of a planet (or the passengers of a spacecraft), but the technical challenges are enormous, and the benefits to Mars would probably be slow and rather minor. At this point it is mostly speculation, but of course, all the great things we now take for granted once were little more than dreams and handwaving, so who knows? Perhaps we find a way to produce a magnetic fields big and strong enough that would endure long enough with little maintenance, and perhaps we find a way to replenish Mars' atmostphere quickly enough to make it worth doing.

      • As for the actual idea - I think it is well-established that a magnetic shield would be just the thing to protect the atmosphere of a planet (or the passengers of a spacecraft), but the technical challenges are enormous, and the benefits to Mars would probably be slow and rather minor.

        On the second point, yes, it would be slow. Probably multiple lifetimes worth of waiting. But on the first point, I was a little shocked at just how simple it might be. 1-2 Tesla is achievable without external power Neodymium magnets sit right about in the middle of that range. The biggest issues will be more mechanical, and for obvious reasons. Considering the implications, something like this might be important for the next earth geomagnetic reversal as well.

        Perhaps we find a way to produce a magnetic fields big and strong enough that would endure long enough with little maintenance, and perhaps we find a way to replenish Mars' atmostphere quickly enough to make it worth doing.

        If this works - we already have a zero or a

        • So, 1-2 Tesla peak in a device how large? A meter? Ten meters? A kilometer? (what are we going to pay for, in other words) sitting in the middle of nowhere is going to be enough to deflect off-axis charged particles by how much? Bear in mind that Mr. Sun subtends a pretty substantial arc. One such that an entire planetoid object the size of the moon barely obstructs line of sight in a tiny penumbra, sometimes, at 384K kilometers...

          So just how large a region WOULD we have to cover to actually put the en

          • So, 1-2 Tesla peak in a device how large? A meter? Ten meters? A kilometer? (what are we going to pay for, in other words) sitting in the middle of nowhere is going to be enough to deflect off-axis charged particles by how much? Bear in mind that Mr. Sun subtends a pretty substantial arc. One such that an entire planetoid object the size of the moon barely obstructs line of sight in a tiny penumbra, sometimes, at 384K kilometers...

            So just how large a region WOULD we have to cover to actually put the entire planet of Mars in its deflection penumbra? Hmmm....

            If we're going to this place, why not do the same thing for Mother Earth -- put a large cloud of stuff at the lagrange point, reduce insolation, fight global warming. Price is no object! Fantasies are free! Besides, what could go wrong?

            rgb

            Well, that escalated quickly! Howbow I just reply to your first questions, because sunlight blocking isn't related nor makes much sense to me.

            The physical size of the magnet needed is going to be dependent upon a few factors. Distance away from Mars, and magnetic strength. The earth's magnetosphere is determined by a relatively large planet size, with a very weak magnetic field. .67 gauss at most. The 1-2 Tesla magnet at the Lagrange point will have the advantage of being a much stronger magnetic field

            • by rgbatduke ( 1231380 ) <rgb&phy,duke,edu> on Tuesday March 07, 2017 @06:54PM (#53995629) Homepage

              Well, that escalated quickly! Howbow I just reply to your first questions, because sunlight blocking isn't related nor makes much sense to me.

              Let's try to make it make sense. The solar wind is driven by light pressure. Particles do not, however, follow strict radii out from the sun. They have transverse velocity components as well as radial ones. Also, they are pushed by photons from all over the face of the sun, which have different impact angles, which constantly change their transverse velocity. To put it another way, the particles driven away from the sun that will eventually hit Mars have a phase space envelope at least as large as the truncated cone formed by the surface of revolution whose boundaries are the circumference of the Sun on one end and the circumference of mars at the other.

              Now consider a satellite (say) 100m in diameter. Suppose you locate it at the Lagrange point so that it is always along the line between the center of the Earth and the center of the Sun. Question: Will it dim the total sunlight received by the Earth?

              Not measurably. The penumbra of this little satellite extends from its dark side to the tip of the extended cone formed by the circumference of the satellite and the circumference of the Sun. Since the Sun is basically 0.5 degrees from the Earth or the Lagrange point either way, the height of this cone is found from tan(0.5 degrees \approx 0.02 rad) \approx 0.02 rad = 100/H, or
              50x100 = 5 km. So the satellite will cast a complete shadow of the sun that starts out 100 m wide right behind the satellite, then shrinks to zero around 5 km (give or take a km, I'm being lazy) . Beyond that you are in the umbra, which basically means that you are in bright sunlight from the annulus of sun surface visible around the satellite. The further out you go, the smaller the ratio of the occluded part to the directly visible part. By the time you reach the earth, the satellite is completely invisible -- the umbra is irrelevantly dimmed relative to no satellite at all, and it "covers" less of the sun's face from any viewpoint on Earth than a medium sized sunspot.

              Now, if somebody were to tell you "hey, we're going to fix global warming by putting a sun shield in geosync orbit to reduce the total insolation of the Earth", your first concern would be to think about the geometry of that penumbral cone with a known cone height of roughly 5 earth radii vs a 0.5 degree Sun. Just how large would it have to be to reduce total insolation by a single whopping percent? The answer is really, really large. Even at only 5 Earth radii, which is not the distance to a Lagrange point. At the Lagrange point, really really REALLY REALLY large.

              Now, is the solar wind deflection by a magnet going to be exactly like this? No, of course not. The magnetic field doesn't have a sharp cutoff -- it drops off roughly like 1/r^3 from the center of the (presumably dipole) magnet. Also, the force acting on the solar wind (charged only) particles depends on their charge and speed, the acceleration depends on their mass as well, and it has the usual nasty cross products in it so that it only really exerts a large force when particles run across the field at right angles. One would LIKE to think that a small deflection far away produced by a magnet large enough to produce a reasonable deflection a REALLY REALLY large distance away from the magnet could create a shadow as large as Mars, but it is by no means clear that this is the case, and just saying "hey, we can make really big magnets" doesn't actually help. I've got really really big magnets in my house -- ones I've pulled out of dead hard drives, that can basically hold a (small) newspaper pinned to your fridge. IF you get them within an appallingly short distance of the fridge. From a meter away, you can't feel any force at all. If you take an old CRT television or computer monitor and wave this really really strong magnet from ten or twenty meters away, it has

      • TFA was about using a magnetic shield to protect against solar radiation and possibly raising the temperature enough over time to allow liquid water and make oxygen extraction easier... nothing magical.

      • So, keeping a magnet at L1 does seem practical, but if we had a higher temp superconductor that robots could fabricate out of martian soil, that would seem to be the ticket: loop the whole planet.

        • L1 is an unstable Lagrange point though, so this contraption would need constant tweaking to stay in the right spot.

          It would be nifty if we could figure out a way to tack into the Solar wind so this didn't require continuous resupply of propellant.

      • Hey, this is just the first step. Then we crash Europa into Mars and wait a few million years for it to cool and the water to recondense. We'll need the magnetic shield in the meantime unless Europa has enough of an iron core that the remelted Martian core turns magnetic.

        Of course, we might hasten the cooling by a few hundred thousand years if we install a cloaking device at the same Lagrange point so that Mars is in its shadow.

        All it takes is money, right? Unbelievably enormous amounts of money. And ti

      • Everyone knows there is an ancient Martian atmosphere generator [youtube.com] beneath the surface.
    • by Joce640k ( 829181 ) on Tuesday March 07, 2017 @06:53AM (#53991233) Homepage

      They don't mention much about how this magical magnetic barrier is going to be generated or powered.

      If only there was an easy way to make working superconductors in near-zero ambient temperature environments.

      (or even an easy way to read articles from the comfort of home)

      • They don't mention much about how this magical magnetic barrier is going to be generated or powered.

        If only there was an easy way to make working superconductors in near-zero ambient temperature environments.

        (or even an easy way to read articles from the comfort of home)

        Or Neodymium magnets. Remarkably strong.

        • They don't mention much about how this magical magnetic barrier is going to be generated or powered.

          If only there was an easy way to make working superconductors in near-zero ambient temperature environments.

          (or even an easy way to read articles from the comfort of home)

          Or Neodymium magnets. Remarkably strong.

          Oh, that would be fun: launching thousands of tiny magnets into different orbits...

      • The problem is getting far field effects from an itty bitty coil - no matter if you have a 20T field at the middle, how long before that dissipates to less than Earth's magnetic field? Hint: they make these crazy fields in Tallahassee, and they don't affect compass needles on the other side of town. Mars is a few orders of magnitude bigger than a city...

    • This is why that won't happen any time soon. If we intend to discuss here all potential NASA projects, slashdot must be dedicated to that, along with 10 other websites.
      • This is why that won't happen any time soon. If we intend to discuss here all potential NASA projects, slashdot must be dedicated to that, along with 10 other websites.

        Beats hell out of the endless stories on Apple's missing headphone jack.

    • "They don't mention much about how this magical magnetic barrier is going to be ... powered."

      Windmills. They work everywhere and are dirt cheap dontcha know? Seriously, I should think solar power. How much is needed? A lot I'm sure, but perhaps not as much as one might think. Basically, unlike here on Earth, the magnetic field they propose doesn't envelop the planet, it just deflects the solar wind a little bit -- just enough so it misses the planet.

      Not the dumbest idea I've heard this week.

      But I suspe

    • They don't mention much about how this magical magnetic barrier is going to be generated or powered. They also don't really know how long it will take a habitable atmosphere to form assuming it works at all, or what happens to everything if the shield fails at a later date and what kind of upkeep it would require. It sounds a lot like wishful thinking and hand-waving.

      Didn't RTFA did ya?

      1 - 2 Tesla or 10K to 20K Gauss is what they are looking at. It is quite possible that you won't even need a powered magnet, as Neodymium magnets are already in that range https://en.wikipedia.org/wiki/... [wikipedia.org].

      The confusion probably comes from the idea that the magnet needs to be extremely powerful. This is not the case. At the earth's surface our own magnetic field tops out around 0.65 gauss.

      Placing the big dumb magnet at the Lagrange point and having it deflect the charged particl

    • we just need to get Arnold Schwartzenegger's ass to Mars, he will take care of the rest

  • Let's do it... (Score:5, Insightful)

    by Camel Pilot ( 78781 ) on Tuesday March 07, 2017 @03:14AM (#53990703) Homepage Journal

    What the hell are we waiting for? Having 4.2 Billions years of evolutionary investment held captive at the bottom of one gravity well is not a good long term strategy.

    • All life has the same amount of evolutionary investment by your measure. So let's send some microbes and call it a day. Don't terraform Mars, how about let Mars be Mars.
    • by Kjella ( 173770 )

      What the hell are we waiting for? Having 4.2 Billions years of evolutionary investment held captive at the bottom of one gravity well is not a good long term strategy.

      And for the first 4.19999 billion years we didn't have homo sapiens. For 4.1999999 billion years ago we were in the Dark Ages. And 4.19999999 billion years ago we fought WWI without any real rocketry. Dragging in astronomical time scales is more an argument that there's no urgency at all, if life survives 0.01% longer than it has we have hundreds of thousands of years to make it to the stars. And we could survive a dino-killer here on Earth, of course by we I don't mean 99.9% of us but humanity as such.

      • by Maritz ( 1829006 )
        The nuclear stockpiles that exist on this planet make it pretty unlikely we'll see out the next century or so. Doesn't even have to be a deliberate act. More likely to be accidental. Given that, I think the urgency is warranted. Our ability to deal with existential threats is one of our worst competencies.
        • by Kjella ( 173770 )

          The nuclear stockpiles that exist on this planet make it pretty unlikely we'll see out the next century or so. Doesn't even have to be a deliberate act. More likely to be accidental. Given that, I think the urgency is warranted. Our ability to deal with existential threats is one of our worst competencies.

          The most powerful nuke tested was 50 MT. The world's total nuclear arsenal is around 6400 MT. The dino-killer was 100.000.000 MT. We could obliterate all major population centers and contaminate the surrounding areas. Whirl enough dust into the athmosphere to send the planet into nuclear winter. We still wouldn't have enough nukes to hit every rural farm in the middle of nowhere. Maybe Florida would be more like Canada, but it wouldn't be uninhabitable. It would be the end of civilization as we know it. It

          • It wouldn't be the end of humanity as we know it.

            I think that probably depends on how widespread the bombing is. Spread enough radiation around and you're sure to see things change one way or another, even if it's "only" because people have to live substantially differently as a precaution for some years.

    • No matter what happens to Earth, it's going to be a lot more habitable than Mars will ever be.

      Over the last 500 million years, Earth's temperature has varied by less than 15 degrees C in either direction. Mars' average temperature is about 70 degrees C less than that of Earth.

      One could make similar arguments regarding Earth's atmospheric pressure, oxygen level, magnetic field, and so on.

      It's hard to conceive of a human or non-human catastrophe will disrupt Earth to the point that it's less habitable than Ma

  • Screw Mars, maybe we should be thinking about putting one at EARTH's L1 point.
    • by Maritz ( 1829006 )
      Earth has a powerful magnetic field. You might as well suggest oceans. ;)
      • Earth has a powerful magnetic field.

        for the moment.

      • Earth has a powerful magnetic field. You might as well suggest oceans. ;)

        Putting one up to protect earth might be a fine idea some day. The Magnetic field of earth (~.65 gauss at the surface) is possibly making way for one of it's reversals at present - it's certainly weakening. If it approaches 0, an artificial magnetic field might come in handy to tide us over until the earth gets it's own back.

    • I wanted to say that there was a movie where they did something like that, like one of the Highlander movie sequels, but then I remembered there aren't any sequels to Highlander.
  • by goodmanj ( 234846 ) on Tuesday March 07, 2017 @04:17AM (#53990841)

    This is a cool idea, but do the math: if you were able to shut off the reported 0.1 kg/s of atmospheric mass loss, how long does it take to double the atmospheric mass (about 2.5 x 10^16 kg)?

    Related question: does it count as terraforming if the Sun blows up before you finish the job?

    • This is a cool idea, but do the math

      The idea is to start a positive feedback loop - heat up the planet to release currently frozen volatiles (CO2, etc), which in turn will increase the temperature even more.

      Over a period of time, the dynamics of this process will be exponential, until it becomes self-limiting (i.e. most of the volatiles have been released into the atmosphere and further temperature increases will not lead to more of them being released.)

    • by Xyrus ( 755017 )

      If the sun blows up, that would be terra-unforming. No points awarded.

      • If the sun blows up, that would be terra-unforming. No points awarded.

        ...but, but but, we did something that transformed a whole planet!!! That counts for something!
        *snort* :)

  • by Dunbal ( 464142 ) * on Tuesday March 07, 2017 @06:09AM (#53991133)
    I know a kid inventor who can do wonders with stuff from Wal Mart I'm sure he can come up with something.
  • Wasn't that also suggested at some point? Putting a shield, possibly in the form of a large solar power plant, at Venus' L1 Lagrange point to cool off the planet until the CO2 can be siphoned (and shipped to Mars?).
  • While not enough of a change to allow walking around without a space suit, this would make human exploration of the planet a much easier task.

    Sure, if there are still humans in a few million years. But shielding the atmosphere and waiting for the planet to warm is not a feasible approach to terraforming.

    If you want to terraform Mars right now, you first need to thicken the atmosphere by warming the polar caps. You then have lots of time protecting that atmosphere from solar wind.

  • by tomxor ( 2379126 ) on Tuesday March 07, 2017 @08:42AM (#53991489)
    Trying to generate a magnetosphere in place is hard, but this is quite a strategic alternative. Nothing is cheap when talking about Mars, but this has to be one of the cheapest long range construction projects with the largest potential change to the planet.
    • by Baron_Yam ( 643147 ) on Tuesday March 07, 2017 @09:27AM (#53991705)

      There's a lot of 'Mars stuff' I'm surprised we don't toy with more. Or maybe we are, but it's all in some lab because (so far) that's good enough given our current level of technology and knowledge.

      You'd think, for instance, somewhere someone should be experimenting with the minimum requirements for rendering Martian regolith into non-toxic, fertile ground. Toying around with the power requirements to augment Martian sunlight and temperatures to levels required to support Terran plants or trying to engineer plants that will grow and thrive at Martian insolation levels. Figuring out how to reliably supply the required power.

      Or playing around with in situ production of building materials, automated mining and refining equipment, etc. Maybe we just don't have a firm enough grasp on what the Martian surface is actually like to bother starting with that. Send a robot to make a little red brick igloo, you know?

      I'd certainly be up for a really inhumane experiment - sending a colony of mice in a sealed environment to see multiple generations of mammals under 0.38g. And it might be nice to attempt a small terrarium with some automated environmental systems to see how long we can keep it going. And while we're at that... drop a scale model of an airlock and cycle it until it fails so we can see how bad the dust problem is.

  • by jpellino ( 202698 ) on Tuesday March 07, 2017 @09:57AM (#53991853)
    stop watching "Thunderbirds" in the break room.
  • Hey, you can buy a directional electromagnet and all necessary solar capture/transfer stuff needed to handle that kind of a load for on it for only $6000 from Home Depot. Why haven't they done it already??
    </sarcasm>
    What. The. Fuck.

  • by fahrbot-bot ( 874524 ) on Tuesday March 07, 2017 @12:42PM (#53993035)

    Magnetosheath, Magnetopause, Magnetotail

    Carnac the Magnificent [wikipedia.org]: (opens envelope) "Things X-Man Magento doesn't want to see on his annual medical report."

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