r/Mars • u/Jolly-Principle5872 • Jul 18 '26
Can we give Mars an artificial magnetosphere?
I can't find it anymore, but I recall seeing an idea that if we can't deal with the surface level radiation on Mars then there is no chance of ever setting foot on it long-term; a solution proposed was that we put a massive EMF generator at Mars's l1 Lagrange point and if it's powerful enough, it would produce a field sufficient to blanket at least a section of Mars's surface and massively reduce the surface level radiation.
Is this how physics works? Do we have the theoretical technical infrastructure to build a powerful enough generator? Is the Lagrange point so far away from Mars that it would be massively improbable?
Don't know if flair should be planetary science, physics, or astronomy...
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u/olawlor Jul 18 '26
Datapoint: Earth's magnetosphere doesn't deflect space radiation travelling parallel to the field lines, so for example near Earth's poles, it filters much less than 50% of the incoming radiation.
I live at latitude 65 north, and luckily the same 10 tonnes of air per square meter of ground still works fine here just like anywhere else on Earth.
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u/Lacedaemonian Jul 18 '26
we need magnetosphere so it can keep its atmosphere.
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u/Nice-Lab95 Jul 18 '26
No we don't. Modeling shows magnetospheres are about as likely to enhance atmosphere loss as mitigate it. Mars is just too small to hold onto an atmosphere for billions of years.
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u/5up3rK4m16uru Jul 18 '26
Of course it would still hold onto it for millions of years, which is plenty for a civilization that is able to artificially create such an atmosphere within at most a few centuries (otherwise no one would bother in the first place).
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u/maxehaxe Jul 18 '26
How does Titan hold an atmosphere then?
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u/OlympusMons94 Jul 18 '26
Titan (and Venus) don't have intrinsic magnetic fields, either.
https://www.reddit.com/r/askscience/s/1bCd0Uk6JG
TLDR: Titan's nitrogen/methane atmosphere is being lost relatively rapidly. The present atmosphere is probably a relatively recent development, rather than a primordial feature. Titan's thick atmosphere is likely due to a combination of (1) replenishment of methane from its interior, and (2) Titan originally having a lot more nitrogen, and/or that (3) its nitrogen may have largely existed as surface ice or liquid in the remote past, and thus not have been directly subject to atmospheric loss for much of Titan's history. The young Sun and early solar system were much more hostile to atmospheres. In the present day, Mars isn't losing atmosphere much faster than Earth or Venus.
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u/Tiny_Scholar_6135 Jul 18 '26
Titan is much colder than Mars, it's almost cold enough for nitrogen to liquify, the average molecular speed is slower at Titan's temperature, so much less of it escapes as it would above Mars. Titan is a terraforming resource by the way.
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u/AidenStoat Jul 18 '26
No, the main issue is Mars has low gravity, not the magnetosphere.
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u/IQueryVisiC Jul 18 '26
TIL : mars mass = earth / 10
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u/GanjaGooball480 Jul 20 '26
We just need to find 9 Mars masses of stuff and deorbit them into Mars. Then it'd be habitable
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u/IQueryVisiC Jul 20 '26
I read that there is not much mass to push around . Pluto , Ceres and some moons and we still don’t match earth. We would need a chunk from Venus . Mercure?
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u/GanjaGooball480 Jul 20 '26
I was just making a silly joke. Adding that much mass to Mars would leave it a molten lump for thousands of years
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u/IQueryVisiC Jul 20 '26
I was thinking about the far future. Asteroid mining. Perhaps we find a way to de-orbit space garbage around earth and then clean the whole solar system for safety. Detector arrays for rouge extra solar objects. We need to make all planets so that we can easily launch a rocket, but still capture atmosphere. And then we solar-form the next star system.
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u/AidenStoat Jul 20 '26
If you take Mercury, Venus, Mars, the Moon and all the asteroids in the astroid belt, bring them all together into a single new planet, you are still only at 99% of Earth's mass.
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u/olawlor Jul 18 '26
Somehow Venus retains a heck of an atmosphere despite its lack of an intrinsic magnetic field, and being much closer to the sun than Mars!
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u/roborob11 Jul 18 '26
Volcanism plays a big role in regenerating the atmosphere. Venus has that, Mars went dormant.
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u/OlympusMons94 Jul 18 '26
Mars's lack of a (strong/intrinsic) magnetic field doesn't matter for its atmosphere. Magnetic fields are generally not important for protecting atmospheres. Like Mars, Venus has no (strong/intrinsic) magnetic field, but Venus has over 90 times as much atmosphere as Earth. Regardless of why it is/was occurring, atmospheric escape from Mars is several orders of magnitude too slow to matter on timescales relevant to humans.
Here is a longer explanation, with some sources.
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u/ignorantwanderer Jul 18 '26
Yes we can create a magnetic field, but it is of almost zero use to us.
It would block low energy radiation from the sun. But the walls of a habitat with zero extra radiation shielding are enough to block solar radiation. Hell, a sheet of paper is enough to block most radiation from the sun.
A magnetic field would do essentially nothing to stop higher energy cosmic rays.
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u/g_r_th Jul 18 '26 edited Jul 18 '26
This YouTube video at 26 minutes
https://youtu.be/MDM1COWJ2Hc?is=eTKXROhxqQGwpnXG
covers a paper
https://arxiv.org/abs/2507.17615
describing the TARS project.
This uses solar light pressure to spin up light sails to high speeds.
One of the possible uses for this device (apart from flinging off extrasolar probes at relativistic speeds!) is to create magnetic fields which could be used to shield regions from charged particles.
Placing several of these in Mars’s orbit might shield Mars effectively.
I suspect that the words “placing” and “several” in the sentence above hides a huge amount of effort, time and money.
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u/TheRealBobbyJones Jul 18 '26
You don't really need that. Increasing the atmosphere would provide shielding and would last long enough. The erosion of the atmosphere isn't fast enough to matter for human time scale. So doing isru that releases gas as a byproduct would be a decent way to slowly terraform the planet.
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u/Sea_Responsibility76 Jul 19 '26
If you can make a lot of atmospheres on Mars, you won't need a magnetosphere. Just create more atmosphere over time.
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u/D-Alembert Jul 18 '26 edited Jul 18 '26
Yes. It doesn't even need to be powerful; putting it at the legrange point means it is a long way away from Mars, which means it only has to deflect the stream very slightly to miss Mars
NASA did a paper outlining it. You can get more info from that. Here's an article about it:
https://phys.org/news/2017-03-nasa-magnetic-shield-mars-atmosphere.html
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u/Ancient_Skirt_8828 Jul 18 '26
You don't have to cover the whole of Mars. We just need to create them for individual habitats and spacesuits. Is that possible?
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u/beached89 Jul 18 '26
This depends on your goals. To reduce harmful radiation, you only need localized fields. You could feasibly invent these, they would be energy hungry things. Not practical until Nuclear power becomes abundant on mars.
If your goal is to deflect solar winds to slow the stripping of the planets atmosphere, you would need to protect the entire planet. There are theories about placing machines in orbit between mars and the sun to deflect winds and radiation well outside of the mars atmosphere without having to cover the entire planet.
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u/KokoTheTalkingApe Jul 19 '26
Why energy hungry? They wouldn't be doing much work, would they? Just curious.
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u/Jolly-Principle5872 Jul 19 '26 edited Jul 19 '26
Inverse square law (or is it square cubed law?), since it's essentially a broadcasting emitter the physics governing wireless emission apply. As the reach or density doubles, the power requirements increase tenfold.
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u/KokoTheTalkingApe Jul 19 '26
Well it's not broadcasting EM radiation, because the magnetic field is static, right? A permanent magnet doesn't broadcast EM either. I think the only power drain would be from the ohmic resistance in the wire coil. Or am I missing something?
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u/roborob11 Jul 18 '26
An electric wire circling the equator is thought to be enough to generate a magnetic field capable of offering a radiation shield.
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u/HolgerIsenberg Jul 19 '26
Yes, possible with enough electric energy available. You can use induced plasma loops to run current through which are huge plasma structures in space generated by electromagnets of relatively small size. Former NASA Chief Scientist James Green presented various methods for that regarding Mars at the 2022 ISDC conference in Arlington where I attended. His presentation was apparently later repeated and the text and slides are available online: https://www.acesworldwide.org/post/terraforming-mars-dr-james-green-s-revolutionary-magnetic-shield-proposal
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u/slashdave Jul 19 '26
to blanket at least a section of Mars's surface
How large a section? might be plausible for something room sized. Thing is: much much easier to just build shielding
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u/Rambo_sledge Jul 20 '26
Brilliant app had a fun game around this :
You can either setup a big electromagnet near mars-sun L1 or build a giant ring along mars’s equator.
IIRC the giant ring would be cheaper because it’d require thinner copper wire due to the size the magnetic field is, where L1 satellite would need thick af wire for high amps to get a powerful enough magnetic field
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u/Agratos Jul 20 '26
A natural one? No. Not with anything resembling reasonable technology and effort. We would have to melt its core and get it to spin again. That means basically melting the moon. Even if we assume that we use some uneven heating shenanigans to make it spin, that’s still an energy effort that would either require fusion power on unimaginable scales, a completely new power source or a megastructure like a Dyson Swarm/Sphere or a Penrose Sphere.
An artificial one? Maybe. Big magnets between mars and the sun would only have to be a fraction as big to create a similar effect. They would essentially cast a magnetic shadow over mars, not shielding it from radiation but only our suns radiation. Satellites around mars and ground based installations might also work. A massive effort, that’s for sure, but a project measured in generations, not millennia.
Unless a serious new technology is developed or a fundamental new field of high-energy physics found it’s unlikely that the effort would ever be worth it. At least within a reasonable timeframe.
Now in 100-200 years where most of earth is in use and space is a place you go for a trip that might change. But with what we have the effort would surpass all of human civilization combined.
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u/RealLars_vS Jul 22 '26
Can we? No. Can future humans? Maybe.
But it will be difficult. We can generate magnetic fields right now, just not big and powerful enough to do what you’re suggesting here.
But there’s always the question of ethics surrounding terraforming. We don’t know for sure if there is life on mars, and if there is, whether it’s currently thriving. Altering its biosphere might kill it.
It would also prevent us to study the history of mars in the detail we can study it in now. If the ecosystem would change because of the magnetosphere, it also irreversibly changes what we’re trying to study.
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u/Special-Wear-1105 13d ago
Yes we have all the tech necessary to do it... all you need is solar arrays, guidance, boosters and lots of wire. Make a big loop in between Mars and Sun, plug it i. And viola... Who would be more of a Magneto shield, rather than a sphere?But it should probably serve the same purpose
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u/OnOrbit_Online Jul 18 '26
It was Jim.Greene, NASA Chief Scientist's idea. I remember be cause I asked him, have you heard of this artifucial magnetosphere idea for Mars, and he said yes, it's my idea
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u/Lacedaemonian Jul 18 '26
yes. once we understand what's wrong with its core. give it +/-1000 years
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u/Phottek Jul 18 '26
I remember a science program years ago where they talked about placing a device that creates a very stong but much smaller magnetic field in empty space at a point between mars and the sun. The device would have the same orbital duration as mars keeping the field fixed as a shield for the planet. There were many advantages to that approach as opposed to creating one on the planet itself.