A theory that Mars lost its magnetic field and then its oceans (2022)

https://bigthink.com/hard-science/mars-lost-oceans-magnetic-field/

by mannykannot • 3 years ago

178 176 3 years ago

The headline is a little misleading. It is only a theory that Mars lost its magnetic field. The experiment that was done was on earth, simulated, and so the researchers cannot definitively say that Mars ever had a magnetic field and lost it.

usrbinbash• 3 years ago

and so the researchers cannot definitively say that Mars ever had a magnetic field

We know that Mars had a dynamo-effect in the past from various measurements of the magnetization in its crust, indicating that it had a magnetic field.

https://en.wikipedia.org/wiki/Magnetic_field_of_Mars

jvanderbot• 3 years ago

From my understanding, the evidence for Mars magnetic field is well established from measurements of ejecta and rock banding.

Estimates differ on the strength of the field but I'm not sure there's disagreement on whether there ever was one.

candiodari• 3 years ago

We've analysed old rocks, both from Mars itself and from meteorites and they are magnetized ... so Mars had a magnetic field, for ~1.5 billion years after it's formation.

We also know that for at least the 1st billion years mars had an ocean. In fact, it was probably covered 100% in water for the larger part of that 1.5 billion years.

jonhohle• 3 years ago

    s/\(Mars had\)/it seems \1/

    s/know/think/

When people state things as absolutely true at a cosmic scale that we can’t possibly know with any certainty except what our collectively minimal knowledge allows us to hypothesize, it shuts down discussion, discourages dissent (important in sciences, imho), and taints everything else with suspicion (again, imho, if so-and-so was so certain about thing x we now know is wrong, why should I believe anything they’ve said).

dang2• 3 years ago

Ok, we've consed a theory onto the title above.

ck22• 3 years ago

If I understand correctly, Earth got very lucky with whatever massive planet ("Theia"?) crashed through in early formation to give us the huge core (hence magnetic field for particle deflection) and our absolutely massive moon to churn things.

Seems like both might be needed for "life", maybe anything more than microbes?

Mars core is only half the size of earth's

hinkley4• 3 years ago

The latest density surveys of the earth’s core lead people to claim that chunks of Theia are still discernible in the mantle and outer core. There are splotchy chunks of higher density material down there. And by chunks I mean at least half the size of Australia to almost the size of Africa.

codeflo2• 3 years ago

Africa and Australia describe areas, and the word "chunks" implies volumes... I have no idea whether you mean to imply those chunks are very flat, or that they are in fact volumes with a diameter similar to the width of continents.

ck22• 3 years ago

The simulation gives some insight, the debris was fed back by gravity in a swirl

https://www.youtube.com/watch?v=kRlhlCWplqk

And always a great PBS Space Time on the subject

https://www.youtube.com/watch?v=wnqPqV6DdFQ

xwdv2• 3 years ago

If Earth lost its magnetic field, how long would we last? My understanding is these sort of geological scale events would take thousands of years. Maybe a million.

jwells894• 3 years ago

Yes, atmospheric loss driven by solar wind is a very slow process. It’s the only reason why anybody entertains ideas of thickening the Martian atmosphere… the loss is slow enough that if a civilization has the means to do that kind of planetary engineering, maintenance to offset losses is trivial.

Intuitively I’d expect it to be faster in the case of Earth due to it being so much closer to the sun but I don’t know this for certain.

asdff3• 3 years ago

magnetosphere also shields you from cosmic radiation. long term human settlement would have to be in shielded dwellings, easiest built underground, making the logical case much stronger for just becoming troglodytes on a dying earth than attempting to revive a dead mars as troglodytes.

BurningFrog3• 3 years ago

The remedy would be to put up a magnetic field in the L1 Lagrange point.

It's an option for terraforming Mars.

api3• 3 years ago

I’ve seen some math that suggests that this or perhaps even doing it on the surface with superconducting rings near the poles would take less energy than you might think.

If I recall correctly it was something like the power grid output of the state of California. A lot but entirely within human capacity.

If it were space based you’d have a ton of free continuous solar power.

JohnMakin4• 3 years ago

What would power it?

queuebert4• 3 years ago

We do lose our field periodically. IIRC it reverses over the course of ~100-1000 yr every 20,000 yr or so. During that time, the field is multi-polar and complex and doesn't shield us well. We're still here, nevertheless.

dylan604• 3 years ago

what would this do to radio communications during that course of readjusting?

Zenst• 3 years ago

It always fascinates me the inner core of our planet, after all it is from what we know a swilling mass of hot melting metal and other elements. Which is ever so slowly cooling at a size and scale we find hard to imagine.

Are their events that bring about rapid cooling, or are there mechanisms that maintain or induce the heating, scale of planet and subsequent pressure, or perhaps even cosmic rays impact it are thoughts, but the deeper we look, the more questions we find and still a case of solve less answers than questions and yet to reach that point in which we fully understand it.

Perhaps and very probably, Mars was a thriving ecosystem whilst the earth was still a molten blob of rock. Just the scale of time in the universe well outpaces biological life when talking billions of years.

BurningFrog3• 3 years ago

The major force keeping our core hot is nuclear fission.

https://blogs.scientificamerican.com/observations/nuclear-fi...

JackMcMack• 3 years ago

Interesting read. Though it says the nuclear fission happens in the crust and mantle, not the core.

rvilim2• 3 years ago

You've got to be careful here. This article refers to the heat budget of the _entire_ earth, not the Earth's core. The Earth's core has relatively little in the way of radiogenic elements now.

Most of the heat originating in the core comes from

- The formation of the earth (called primordial heat) - Latent heat (released when iron freezes onto the solid core) - Differentiation (e.g. settling of heavy stuff to the bottom)

The mantle is chock full of radiogenic elements though.

perihelions• 3 years ago

Err, that SciAm author misunderstood that research... what they wrote is exactly backwards. The neutrino observations they're talking about disproved the natural nuclear reactor hypothesis. There is no antineutrino signal from the Earth of the type a nuclear fission process would emit.

https://arxiv.org/abs/1909.02257 ("Comprehensive geoneutrino analysis with Borexino")

What Borexino found was about 25 terawatts of radioactive decay occurring inside the Earth—alpha decay of 238U and 232Th. But, no nuclear fission. If there are fissioning critical masses inside the Earth, the total amount, constrained by neutrino counts, is no more than 2.4 terawatts (and consistent with 0).

pkaye• 3 years ago

From what I understand Mars is smaller mass than earth so it cooled faster. I can imagine other factor like lower gravity that makes it easier for the atmosphere and water to easily escape to space.

Modified3019• 3 years ago

If you’re looking for curious concepts, with no real way to test and verify, you could consider that because of the whole heliosphere thing our solar system has going on, there are higher and lower areas of current flowing through space, and planets could potentially act like a resistor in some circumstances, which could be gained or lost.

Thus far though, science seems mostly satisfied with radioactive decay Edit: https://news.ycombinator.com/item?id=38061230 and the things rvilim mentions

photochemsyn• 3 years ago

The notion that the Earth's atmosphere would rapidly be stripped away if the magnetic field vanished is very unlikely. There's a lot of complex chemistry and physics that control rates of atmospheric escape from planets - but here's an accessible overview:

https://www.scientificamerican.com/article/how-planets-lose-...

Basically the intensity of sunlight (distance from the Sun) relative to the gravitational field of the planet are the main factors. Magnetic fields play a minor role at best, by trapping charged water-sourced hydrogen ions - but those ions can easily lose their charge and then escape to space:

"An important process for hydrogen loss is “charge exchange”, which probably accounts for about 40 percent of the present escape of hydrogen from Earth and most of the hydrogen escape from Venus. Solar radiation creates electrons and positively charged ions in upper atmospheres by tearing electrons off atoms or molecules. Subsequently, charge attraction and repulsion in collisions accelerates ions. On Earth, the magnetic field traps ions, but a fast hydrogen ion can collide with a neutral hydrogen atom and capture its electron. In this exchange of charge, fast ions turn into escaping neutral atoms."

The primary reason Earth doesn't see high rates of hydrogen formation from water and subsequent loss in the upper atmosphere is that the surface temperatures are low enough such that the stratosphere remains very dry. On Mars, due to lower gravity, this stratification should have been less, leading to higher rates of water loss from the upper atmosphere.

neom• 3 years ago

Woke up to YouTube playing this 3 hour video on space the other day and it happened to be at the mars section so I lay and listened to it for a while, pretty fun watch: https://www.youtube.com/watch?v=eSg7TREgNTA

(Mars starts almost exactly 2 hours in)

JohnMakin4• 3 years ago

This is why the whole notion of colonizing/terraforming mars is a fantasy. Any humans there would be dead within a fairly short period and terraforming efforts would be futile due to getting blasted away by radiation.

If we truly wanted to colonize off-planet, the moon is right there.

was_a_dev• 3 years ago

Even if it was lost rapidly, rapid would be on the order of 10,000 years.

That's a whole human history

novalis78• 3 years ago

It’s not a fantasy. Read “A case for Mars” if you are sincerely interested in the topic. Terraforming could dramatically thicken the atmosphere - a process that would take several hundred years. Yes, Mars would slowly lose it, but over 100s of millions of years. So you can keep the planet blue and green. Venus is harder but doable too. Can’t do that with the moon ever. So eventually, if we don’t WW3 ourselves, there will be 3 blue marbles in this solar system and an endless number of space and moon based habitats.

JohnMakin4• 3 years ago

It would be easier and cheaper to terraform/save our own planet than to do this. There is no point.

GolfPopper• 3 years ago

My understanding is that the biggest challenge with terraforming Venus is the atmosphere. It's roughly 93 times the mass of Earth's, and mostly CO2. What do you do with it? Cycling it into the crust would take geologic spans of time. If you just cool it, you get deep oceans or thick glaciers of CO2 covering the planet. If you've got the energy budget to actually remove it from Venus completely (or sequester it rapidly), you've probably got the energy budget to do something easier like relocate a moon or dwarf planet.

Sure, 50-60km up in the atmosphere it's fairly hospitable, but colonizing that isn't terraforming.

asdff3• 3 years ago

You would be bombarded with radiation without a magnetosphere

javajosh2• 3 years ago

I'd personally be more interested in colonizing Venus. What would happen if we construct a large disc and put Venus in the shadow of it? It would cool over time and we could assess what to do then. Perhaps it still has a dyanmo in its center? Active plate tectonics? Water in unexpected places? Venus is very similar to Earth's size, much closer than Mars, and if we could cool it down and terraform it, a better Earth 2 than Mars.

Plus a version of such a disc might come in handy for Earth, if we cannot get warming under control.

bilsbie2• 3 years ago

I’m thinking genetically engineer organisms to transform most of the co2 to a stable solid form.

Maybe floating organisms that can live in the cooler upper atmosphere.

Only catch is we’d need to provide a lot of water. I don’t think the atmosphere has much.

cgriswald4• 3 years ago

I read a paper (that I can't seem to find now) that suggested putting such a sunblock up to freeze out all the CO2, then covering the CO2 with 'tarps' and putting the oceans on top of the tarps to lock all the CO2 in place.

Kostic2• 3 years ago

Kurzgesagt had a nice video about that[0] (and the Mars terraforming as well[1]).

[0] https://m.youtube.com/watch?v=G-WO-z-QuWI

[1] https://m.youtube.com/watch?v=HpcTJW4ur54

anonuser1234562• 3 years ago

https://astrobiology.nasa.gov/news/how-to-give-mars-an-atmos...

samuelec• 3 years ago

A mere attempt to improve SEO.

The article is a non-news and a non-proof. It also contains recycled content, in fact, on top of the article: "October 12, 2023 ... First Appeared on Big Think"

following the link to Big think article we read "September 25, 2023" and "This article was first published on Big Think in February 2022"

dang2• 3 years ago

OK, we've changed the URL from https://daily.jstor.org/how-mars-lost-its-magnetic-field-and... and put the year above. Thanks!

weberer• 3 years ago

I never thought I'd see the day when JSTOR becomes blogspam.

bilsbie2• 3 years ago

Odd that Venus has no magnetic field, and it has a very thick atmosphere, even though it gets 4 times the solar flux as Mars.

contrarian1234• 3 years ago

https://astronomy.stackexchange.com/questions/10189/why-did-...

queuebert4• 3 years ago

Both are related, as Venus is thought to have lost its water through runaway greenhouse. Without water, tectonics and vulcanism are likely to cease, and CO2 is unable to be recycled into the deeper layers of the planet. It builds up on the surface, and you get a 70 bar atmosphere of mostly CO2. This "runaway" feedback loop is one of the main reasons why global warming should be avoided, in my opinion.

soderfoo• 3 years ago

It's quite terrifying to think of a runaway feedback loop leading to the emptying of the oceans, on the scale of happening within a lifetime.

Kevin09210• 3 years ago

Wait I thought the extreme runaway greenhouse effect had been set aside (read that on here a few years ago IIRC), and it wasn't possible for Earth's atmosphere to turn into Venus'.

Found this from April 2023:

How a Stable Greenhouse Effect on Earth Is Maintained Under Global Warming
Plain Language Summary: Observations and model simulations have shown that Earth maintains a stable longwave radiative feedback process. When the surface warms by 1 K, Earth allows for 1.7 to 2.0 Wm−2 of extra thermal cooling to escape to space in cloud-free conditions. Recent studies have claimed that this enhanced thermal cooling to space can be explained by emissions from the surface passing through the atmosphere's infrared window. However, we find that a large portion of the stability actually results from enhanced atmospheric emission during global warming, which arises from the weakening of spectral lines broadening by radiatively inert gases (N2, O2, Ar) as the Earth warms. It is a well-understood phenomenon in spectral physics but has been largely ignored in the feedback literature. As a result, the feedback responses from the thermal radiative effects of greenhouse gases tend to stabilize the climate, rather than initializing a runaway of thermal radiative energy. This study further proposes a simple theory for accurately predicting the clear-sky longwave feedback from climate base states.

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022...

lamontcg2• 3 years ago

This "runaway" feedback loop is one of the main reasons why global warming should be avoided, in my opinion.

The Earth has had a 4,000-7,000 ppm CO2 concentration in the atmosphere before and it hasn't led to Venusification. We've only gone from ~250 to ~420 ppm so far, so we're a long way off, and hopefully we'll stop before we dump another 20+ "industrial revolution units" of CO2 into the atmosphere.

Of course long before then we melt Antarctica and the Earth's climate looks a lot different, but it won't be Venus.

jmclnx• 3 years ago

There is an article in Syy&Telescope that contains a new theory. I did not read it fully yet, but seems Magnetic Field was/is not a factor.

It shows Venus, Mars and Earth is loosing isotopes(?) at about the same rate.

Plus, Venus has no Magnetic Field to speak of and its atmosphere is far denser than Earths.

Sharlin• 3 years ago

Yep, the article is behind the times. The lack-of-magnetic-field hypothesis isn't even the preferred one anymore I believe.

leptons3• 3 years ago

Venus' atmosphere is mostly carbon dioxide and sulphuric acid which is a far different composition than Earth's atmosphere. My guess is the heavier molecules that make up the atmosphere are what makes it far denser than Earth, and gravity likely has much more to do with it than magnetism.

dredmorbius• 3 years ago

Mars's atmosphere is also predominantly CO2, though far thinner.

That's ... somewhat to be expected of any non-life-bearing rocky planet. Free oxygen is unstable, lighter elements (hydrogen, ammonia) would tend to boil off with either low gravity or (relatively) high temperatures (as opposed to the ice-moons of Jupiter and Saturn, especially Titan).

wheelerof4te4• 3 years ago

Not to mention Jupiter's or Saturn's magnetic fields, that are far less dense than Earth's, yet both planets have massive gaseous atmospheres.

luxuryballs• 3 years ago

I wonder if these oceans were made of water or some other liquid.

actionfromafar2• 3 years ago

Water

wheelerof4te4• 3 years ago

Probably water, but of different composition to that of Earth's water.

musha68k• 3 years ago

According to NASA Planetary Science Division director Jim Green, a powerful magnetic dipole positioned at the Mars L1 Lagrange Point could potentially deflect the solar wind like a natural magnetic field.

https://www.extremetech.com/extreme/245369-nasa-proposes-bui...

londons_explore2• 3 years ago

Such a project would see no tangible benefits for tens of thousands of years.

Unfortunately, humans tend not to put much effort into anything that has no benefits within ~100 years. "If neither me nor my children will benefit from something, I don't want to invest my time/money."

yincrash• 3 years ago

Wouldn't it still protect humans who visit (or stay on) Mars from the solar radiation?

Levitz• 3 years ago

That makes sense though. I can hardly imagine any effort put 10.000 years ago that would be valuable now, with the technological difference.

fnordpiglet2• 3 years ago

I’m not sure I understand why you think this would take 10’s of thousands of years to yield benefit. The most important benefit is shielding the planet surface from solar radiation and cosmic rays. This would be immediately beneficial to anyone living on the surface and would be essential in any terraforming effort of any duration, long or short. There are proposals that terraform mars in the span of a few generations (orbital solar powered large lasers evaporating the iron oxide and melting the ice for instance). But even without terraforming making the surface less hostile has immediate benefits.

thejackgoode• 3 years ago

A hundred years? I feel like 90% of what happens is done because of election cycles and quarterly reports

Elucalidavah• 3 years ago

To fix that, we need humans that actually expect to live for tens of thousands of years.

Yizahi4• 3 years ago

As soon as that technology level is reached, humanity need not to worry about restoring dead ecosystems, but about preventing total destruction of the existing ones, including Earth. Throwing space rocks will be trivial for any terrorist cell, so any fragile single points of failure will be demolished first (like this magnetic shield, or possible Earth solar shade(because carbon capture doesn't work so far)). Then orbital stations will go, then pressurized domes, then planet surfaces in general.

I think we have no chance at the large space structures, and current age will be considered a fluke of the insufficient lifting capabilities.

aeternum• 3 years ago

Seems like redundancy could solve this. Instead of a single huge magnet you create a constellation of smaller magnets with aligned fields that orbit the LaGrange point.

We're decent at tracking large space rocks, and small space rocks will likely have to be dealt with anyway since some occur randomly.

It's somewhat interesting that terrorism already isn't such a problem for huge skyscrapers. Skyscrapers can be destroyed with just a small fraction of the explosive energy required to launch an orbital rocket yet it rarely happens.

slibhb• 3 years ago

If throwing space rocks is trivial (which I'm not sure I buy), surely knocking them off course will also be trivial.

jeo123• 3 years ago

That will go against climate change (aka global warming) narrative. At this point, doing that is considered blasphemy to those hardcore left. I would reckon your take will only happen after carbon AND methane taxations are well in place and regulated like income taxes per business entities and per individuals basis. Total destruction is like economy public goods. No one will value it unless you can "fence" it as private responsebilities. Leonardo in Look Up was a great exposition of that indifference.

dustingetz• 3 years ago

hive mind is like 40 years out, we’ll all live to see it, we’re watching early stages happen in real-time. once we’re all truly connected there won’t be war

Tuna-Fish2• 3 years ago

Mars wouldn't instantly become uninhabitable once the shield collapses. Atmosphere loss is something that occurs over the timespan of millions of years, it would be entirely reasonable for a civilization with sufficient spacelift capacity to terraform Mars without a shield, with the understanding that the atmosphere would require active management over millennia.

Also "throwing space rocks will be trivial for a terrorist cell" makes a lot of presumptions about how social organization will work in orbit. IMHO there will never be the spacer society presupposed by so much sci-fi, because any spaceship with an interesting propulsion system is also always a weapon of mass destruction (and not just against orbital infrastructure). The solution to this is that weapons of mass destruction are only owned and operated by large, powerful states with things to lose. It's worked for nukes for 80 years soonish.

arp2422• 3 years ago

"Technology exists" and "technology will be trivially deployable by any terrorist" are two different things.

ICBMs have existed for a long time, as have nuclear weapons. Terrorists cannot "trivially" deploy them.

These kind of extremely powerful magnets will not be trivial, and doing anything in space even less so.

HideousKojima• 3 years ago

I've seen this idea before, and someone did the math showing that while it would be possible it would take an exceptionally large amount of energy to keep the magnetic field running. Not impossible, but I recall it being equivalent to some significant fraction of the energy produced by all power plants on Earth or something like that. Have any advances been made to lower the energy needs for something like this?

bobse2• 3 years ago

Hypothesis, not theory. FFS...

jasongill• 3 years ago

isn't a theory just a hypothesis that's supported by research? the article mentions the published research about this theory (or hypothesis, I suppose)

bobse2• 3 years ago

No. Learn2Science.

johnea• 3 years ago

But for some reason people still want to live there?

Since you'll have to live underground anyway, why not just live in Nevada?

spandextwins• 3 years ago

Humans?

neurostimulant• 3 years ago

Without the magnetic field, the solar wind would strip our atmosphere, and the oceans would evaporate and be lost to space. In other words, Earth would end up like Mars.
The Earth is the only one of the rocky planets in our Solar System to have a strong magnetic field. Its presence is likely one of the major reasons why Mars and Earth are so vastly different.

Venus has much denser atmosphere than Earth despite having weaker magnetic field and being closer to sun (possibly more affected by solar wind?). Why?

A theory that Mars lost its magnetic field and then its oceans (2022)

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