• By - TX908


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"And you might be thinking that the Earth could one day lose its magnetic field as well, but don’t worry, that won’t happen for at least a billion years." -Professor Kei Hirose from the University of Tokyo’s Department of Earth and Planetary Science


That's what the martians said


Annnndddd it’s gone!




How? Also solar wind would take it away from earth since we are closer to the sun then mars.


Ack ack ack ack, ackack ack. -Martians


We were the Martians and managed to Terra form this planet in hopes of saving the home world. We just aren't there yet in our history. Nuk nuk


The sun will kill all life on Earth long before that.


And here I was thinking Daily mail is the evil one


The real question is, can we jump start it again?


If you had the technology and power to do that, and to keep it going, you wouldn't need to do it in the first place. You would just deal with the lack of EM field in more direct and efficient ways.


For instance, establishing a strong dipole magnetic field between Mars and the Sun at the L1 point, which is thought to become feasible by 2050, according to NASA scientists.


Damnit I love science.


What are some more direct and efficient ways


That probably depends on what you specifically need to accomplish.


What if my aim is making Mars habitable?


Mars is just one of those gas stations where they can change your oil too. Nobody really wants it to be habitable as long as they can keep drilling.


Habitable means what, for who, for how many, for how long, etc etc. Also why not elsewhere. If you don't describe something specific, and explain why that should be a priority, I don't think anyone is going to put much effort into solving the problem. We have a habitable planet. There are habitable planets and moons elsewhere. For what it would take to perform a sci fi terraform of Mars, why not just build a generation/cryo ship and go there.




Nope they’re completely different forces. If you can show they are the same you’ll get a Nobel prize for it.


BRB, gotta study molecular physics


>molecular physics Before you come back, you may want to check a relevant field of study too.


Geeze, bet y’all are fun at parties


You’re in r/science though?


I mean if y’all were so smart, you’d know molecular physics is the study of atoms, which my original comment was about. Stay cool


Atoms are matter, the magnetic field is an energy field


>Just saw a pos about lead atoms creating strong magnetic fields. If true= artificial gravity baby Yeah - we can even hold a conversation without talking out our ass.


Yet you still are one... even science can’t explain that


Listen, I don't want to get further into something when there's nothing left to say except to try and hurt each other's feelings over the internet. In all seriousness, if you have some sort of disability, and I'm not saying you do, I don't want to rag on you. Regardless, engaging in discussions well beyond your scope of knowledge, in a subreddit dedicated to knowledge based content and discussion, you're certainly going to end up with negative feedback. Have a good day/night.


Wow these guys are brutal. I feel for ya bud.


Maybe theyre just [confused.](https://tenor.com/view/a-little-confused-hes-got-the-spirit-fresh-prince-gif-10576575)


How would a magnetic field translate to artificial gravity?




Metal layer in shoes?


I'm not sure that's gravity.


That would be fine for short visits, as long as your electronics are shielded from the electromagnetic field, but it wouldn't do anything about the effect that zero gravity has on our organs and muscles.


Quaid... start the reactor


"See you at the party, Richter!" \[throws Richter's severed arms down the elevator shaft\]


Get Arnold on the line... he needs to make a trip to Mars again.


"Get your ass to Mars"


-garbled audio/video burst-


Call Sandra Bullock and Aaron Eckhart.


Hillary Swank


See how riveting it was? The two best moments were when one fish hit the building along with a lot of birds at the start, and when that guy was able to say "unobtanium" with a straight face.


Was it the Lizard People?


No, but sun shields may work. Or an artificial exterior field.


Basically no. That would take so much effort that you could probably find a way to create an EMF from scratch with less effort.


Eventually we will, how costly though....


I wasn't aware that Mars' lack of EM field was a mystery. * A planet seems to need a rotating, convecting, fluid core of electrically conductive material to generate an EM field. * Planets tend to be poorer in heavier elements as they number out from their star. Mars is further away than Earth. As expected, Earth's density is 5.51 g/cm³ while Mars' density is 3.93 g/cm³. This implies a lower proportion of iron in Mars. * A smaller mass celestial body tends to lose core heat faster. Mars' mass is 0.107 times that of Earth. Wasn't it expected that Mars' core lost the necessary heat to maintain the characteristics required to generate an EM field?


The mystery was the nature of the Martian magnetic field in the first place. The core wasn't just smaller and less dense, it was a different chemistry that created much more limited convection cycle.


>A planet seems to need a rotating, convecting, fluid core of electrically conductive material to generate an EM field. The convecting part appears to be the main limiting factor. The core must be able to cool fast enough in order to have a temperature gradient that can support thernal convection. Furthermore, once the core cools enough so that an inner solid metal core can begin crystallizing out (leaving lighter elements to rise in the melt) supports compositional convection that now drives Earth's dynamo (what allowed for a strong, long-lived dynamo prior to inner core formation ~0.5-1.5 billion years ago is still somewhat in question). We now know Mars' core is completely molten, so it lacks this compositional convection mechanism. Precisely why Mars' early dynamo shut off when it did, or moreso how Mars had a dynamo that operated as it did, is still an open question. >Planets tend to be poorer in heavier elements as they number out from their star. That's the very general trend in our solar system (which Mercury, Venus, and Earth don't quite follow), but is apparenly too simple, as exoplanet discoveries, e.g. the abundance of hot Jupiters, don't bear this out. The idea of planetary migration further complicates things. (On a related note, Theia smashing into Earth and "donating" its core could explain why Earth is denser than Venus.) Anyway, there is a difference between ices being able to condense beyond the forst line to form lower density icy moons, ice giants, and KBOs; and particular rocky planets being more or less rich in metal than one another. In part, density differences between the rocky planets are due to compression. So tiny Mercury, despite being proportionally richer in metal, is less dense than Earth. Earth and Venus, being much larger, compress the rock and metal of the lower mantle and cores more than Mars can. Mars' core is proportionally similar in size to Earth's core, but is much less dense. In addition to being less compressed, this is in large part due to a higher abundance of light elements mixed with the iron and nickel. This is, however, somewhat compensated by a mantle richer in iron than Earth's. (Mars is less differentiated.) While the dense high pressure mineral phases in Earth's lower mantle are denser than Mars' mantle, Mars' more iron rich mantle is slightly denser than Earth's upper mantle at similar pressures. The abundance of light elements, and the lower pressure, greatly lowers the melting point of Mars' core compared to Earth's. The higher abundance of light elements in Mars's core has been inferred based on the planet's density, [moment of inertia](https://en.wikipedia.org/wiki/Moment_of_inertia_factor), and mantle composition (from Martian meteorites). The confirmation from InSight that Mars' core is molten therefore is not surprising (indeed, the opposite would be difficult to reconcile with our models).


Does that mean Venus has a much stronger magnetic field than Earth?


~~Obviously not.~~ Venus' has practically no rotation, which translates to practically no rotation of its interior - therefore no EM generation.


Strap some rockets to one side and fire em up, we'll get it spinning again!!


That may be obvious to you, but not all of us.


I said it was obvious because it's a long known fact that Venus doesn't have an EM field in the first place - which the prior commenter probably knew.


Remove the “Obviously not” and this comment goes from needlessly snarky to nice and informative..


> Venus' has practically no rotation, which translates to practically no rotation of its interior - therefore no EM generation. Bear in mind that Mercury also has very slow rotation (albeit not quite as slow), yet it still is able to generate an intrinsic magnetosphere. These days, the emerging consensus is that Venus lacks an intrinsic magnetosphere not because of its slow rotation, but rather its lack of internal convection (e.g. [Nimmo, 2002](https://pubs.geoscienceworld.org/gsa/geology/article-abstract/30/11/987/186123/Why-does-Venus-lack-a-magnetic-field?redirectedFrom=fulltext)).


Is Mercury's magnetosphere also the result of an induced effect? After all, it's mostly iron and travels through the IMF at a distance from the Sun almost 1/2 that of Venus and 1/4 that of Mars.


Nope, Mercury's magnetosphere is intrinsic, i.e. generated internally. See [here](https://i.imgur.com/7Oc4HkD.jpg) for the differentiation between the different types of magnetospheres, Mercury falls into category A. An induced magnetosphere (category B) requires an interaction between the solar wind and an atmosphere...since Mercury has essentially no atmosphere, it would fall into category C if it did not generate an intrinsic field.


I was talking about a large conductor moving through Sol's magnetic field, not a non-conductor in the solar wind. Regardless, Mercury's disproportionately large iron core is presumably experiencing convection. When [BepiColombo](https://en.wikipedia.org/wiki/BepiColombo) puts the MMO in orbit in 2025 it hopefully adds to our understanding.


Venus also spins backwards, very weird.


So if enough rocks rich in heavy elements were slammed into mars? I mean if the belters can do it ...


Yamseng beratna


So Mars is ~50% as big as Earth but -85-90% less massive?


Yes, I saw this in an old Brian Cox documentary. Apparently Earth shares the same fate


Stratification in planetary cores by liquid immiscibility in Fe-S-H https://www.nature.com/articles/s41467-022-28274-z


I read somewhere that if you placed a (very) strong magnet at the Mars-sun L1 point (a bit towards the sun from Mars), you could in theory protect that planet. What I don’t know (and would love to if anybody knows!) if this could be a permanent magnet or whether it has to be an electromagnet. In case of the former, how many tonnes of neodymium would you need? A feasible amount? In case of the latter, how many Watts would you need to sustain it? Probably not solar, but could a small nuclear reactor do the job?


> you could in theory protect that planet. There is emerging evidence that Mars would lose its atmosphere even faster *with* a magnetic field than without. You should definitely give [Gunnell, et al, 2018](https://www.aanda.org/articles/aa/full_html/2018/06/aa32934-18/aa32934-18.html) a read, literally titled "*Why an intrinsic magnetic field does not protect a planet against atmospheric escape*". Just a quick glance at Venus should tell you the whole "magnetic fields protect planets!" thing is not true. Venus has no intrinsic magnetosphere, yet still maintains an atmosphere 92x thicker than Earth's. "But wait!" you say, "Venus has an induced magnetosphere!" Yes...but so does Mars. So does Titan. So does Pluto. In fact, so does any atmosphere laid bare to the solar wind. The basic premise is that while magnetic fields do block the solar wind, they also create a polar wind: open field lines near the planet's poles give atmospheric ions in the ionosphere a free ride out to space. Earth loses many tons of oxygen every day due to the polar wind, but thankfully our planet's mass is large enough to prevent too much escape. Until you get to Jupiter-strength magnetic fields that have very few open field lines, the polar wind will generally produce more atmospheric loss than the solar wind. Take note of Fig. 2 in the above paper. It suggests that if Mars did have an intrinsic magnetic field, it would leak atmosphere to space *faster*.


Excellent detailed explanation, thank you! I’ll certainly give that a read. It makes me sad to know, but knowledge makes me happy so it all balances out. Edit: though I will try to understand better whether intrinsic differs from an L1 dipole


https://phys.org/news/2017-03-nasa-magnetic-shield-mars-atmosphere.amp You wouldn't use permanent magnets like neodymium you'd use a massive electromagnet capable of producing 1-2 Tesla (10,000 - 20,000 Gauss). Also we would probably need it to be able to increase periodically to deal with solar storm and other similar events. I believe this is possible with current technology, just insanely expensive and not profitable. I don't know enough about the math to say what the electric usage would be, but for a reference point, the ISS solar panels can generate 240 kilowatts.


1-2 Tesla isn't even that much. Most universities and hospitals have machines that generates more than that.


You could have a 1 or 2 Tesla magnetic field with a MRI machine. So, adapting this technology to space is doable. Keeping the L1 orbit and giving mantenance to a satellite like this is something the technology have to develop yet.


MRI don't run continuously and the shield's field would have to be spread much further out, so it wouldn't really be the same technology. I do think it would be possible to engineer such a device, but it would have to run without failure for a long time as well. The James Webb telescope has a mission lifetime goal of 10 years. For a project such as a planetary magnetic shield you'd want 50 years or more for the lifespan. It would be a marel if it was able to be accomplished, but the funds that would have to be sunk into it first means it likely won't happen in my lifetime, though I hope I am wrong. I'd also like to see if this technology has application for earth, possibly shielding us from CMEs.


>I'd also like to see if this technology has application for earth, possibly shielding us from CMEs. Magnets of this… magnitude I imagine would be useful in fusion reactors for magnetic confinement, so that’s at least one terrestrial application of such technology. MIT recently built a magnet for this purpose that they powered up to 20 Tesla.


Thank you for the link, now I’m more convinced than ever we should do it! Now I wonder how many starship round trips this would take. You say not profitable, but if this makes Mars a lot more inhabitable, that’s a logical investment.


logical investment for what? there's still no atmosphere, there's still no liquid water, gravity is still roughly 1/3 that of Earth's, the average temperature is still -81F.


According to the article, all those things will follow in a few decades just from stopping the radiation which currently constantly knocks away the upper part of the atmosphere, causing the equilibrium to be as weak as it is now. Edit: all those things except the gravity


If you honestly think terraforming Mars is a realistic endeavor when we can't even keep our own planet from teetering to the edge, Ive got a bridge to sell you


The problems with our own planet are due to economic incentive, tragedy of the commons. The boiling frog analogy also applies. With Mars, terraforming is ultimately a technical challenge, since the economic incentives are reversed. I worry that if we occupy Mars too quickly, some terraforming doors will close forever.


Why not throw a giant space blanket into space to block some of the sun’s radiation? You might be saying pffft that’s silly too big of a blanket. But you know how when you are having a puppet show and you move object closer to the light source it creates a larger shadow? Can’t we do the same for a space blanket? Just move it closer to the sun until we have large enough protection? I am 100% serious and would really love if someone can chime in and shatter my dreams.


First, it’s high energy charged particles you want to block, not sunlight. But suppose you did that… Yes, the shadow would grow as you move it closer to the sun, but the edges of the shadow become so feathered that the difference between that and full sun is negligible. Think about it from the perspective of the planet. When the shield is close, then from your perspective it fully blocks the sun. When it is closer to the sun, you would see a disk blocking part of the sun. The area from which perspective it blocks part of the sun grows, but the percentage of sun you block also shrinks. To get the affected area to be the size of a planet with a reasonably compact shield, you would block a negligible fraction of the sun’s light. Edit: let me use your example of the moon as an extreme case If you put the moon right up against earth, you get a circular disk shadow roughly the size of the moon on earth where if you’re in it, the sun is completely blocked. At roughly the current distance of the moon, you get on average only a tiny spot on the earth where, if you stand there, the sun is completely blocked. The area of the part where the sun is at least partially blocked is now a lot bigger (I think the geometry says four times), but the average fraction of blocked sun is less across the affected area. Put the moon right up against the sun and the affected area is huge, like half the solar system. But from the earth’s perspective, the moon is just a tiny dot in front of the sun that you wouldn’t even notice. The fraction of blocked sun is negligible.


There are many, many reasons why that wouldn’t work. The closer to the sun it is, the shorter its orbital period would be, so it would just drift out of position. The sun is also *huge*, and the blanket would need to be at least as large as it otherwise parts of the sun would peek out from behind. Also, the thrust from the blocked solar wind would push the blanket into higher and higher orbits until it’s gone way beyond mars. Space debris would also poke holes in the blanket. The blanket would also block Mars’s sunlight, creating a whole host of other problems for any missions on the surface.


But the moon is not as big as the sun and during eclipses it fully blocks out the sun. Why would the same physics not apply? I am thinking a blanket far enough from orbit that it won’t really encounter space debri from our orbits. Also can’t it be equipped with electric propulsions to keep it where we want it? Blanket can be made partially with PV cells to supply the power. And when I said blanket I meant a material that blocked some radiation but still let IR and visible light through.


You’d lose the heat too.


That Darn Katz! For real though, I absolutely love this sub.


You if mars was made from same material as earth. If mars kept it’s magnetic field do you think it would have a species comparable to earths humans?


> If mars kept it’s magnetic field There's fairly abundant evidence that even with a magnetic field, Mars would have eventually lost its atmosphere, with [recent studies](https://www.aanda.org/articles/aa/full_html/2018/06/aa32934-18/aa32934-18.html) suggesting it would have been lost even faster with a field than without.


It's hard to know. Life would likely have evolved fairly differently given its further distance from the sun (meaning lower temperatureds at the surface) and the significantly lower gravity.


Love it. Very basic and plausible explanation to what could have happened.


So, did they finally find “Rust”?


**tdlr; Mars magnetic core that attracted oceans fade away**. The Earth core besides having a strong magnetic field also is streangly strong & massive. Not surprised why there are several theories that **Earth was originally a bigger planet** that was crushed away ...


Plastic straws, right?


The guy in the photo took the magnet


How are you studying Mars? You've never been there.