A theory that Mars lost its magnetic field and then its oceans (2022) | Hacker News Reader

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

bigthink.com

178 pointsmannykannot176 comments

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.

> 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...

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."

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

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

Yeah humans can measure progress afterwards but are terrible planners for anything beyond ourselves and next of kin.

I mean, how would you even do maintenance over 10,000 years?

At some point your descendants will be too far to remember the reason but not far enough to need it and they’ll stop wasting resources on a nothing activity.

People still do some maintenance on the 8k year old Afghanistan water system (underground aqueducts) because they are still used today. I’m failing to find some good sources, but when I was there in 2008, it was something the Army Core of Engineers was investigating on my base.

That solves an immediate need though, not a once in a few ten thousand year disaster.

this[1] places them at 3k years old: https://en.m.wikipedia.org/wiki/Qanat

That sounds more right to me than a memory of some random conversations from nearly 20 years ago.

You could write exactly what this is and what you’re supposed to do with it on a big stone plate outside…

Then in 10,000 years, find that an entire religion, culture, and wars were built around the simple maintenance instructions.

Outside, on Mars.

So we have to assume we will maintain the ability for human Mars travel in ten thousand years, that anyone can read English or whatever in ten thousand years, and that the supporting religion didn’t lose any of its wars.

To put this in perspective our first evidence of any human agriculture was 12,000 years ago.

Yeah, maybe, ever heard of the Georgia guidestones? They lasted ~ 30 years...

Progress is exponential until "surprise it is a sigmoid!" I'd argue we are there already, but even if we aren't planting seeds is rarely a waste in the long term.

Only 5,000, but look at the pyramids. They're cool to look at, and the construction is fun to think about, but they're utterly useless. For any sort of 10,000 year space project, there's little (1%) harm in having a 100-year cool-off period to see if it still makes sense and how far technology has come.

Road networks in cities are probably the most durable creations.

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.

All of the terraforming business always seems like just digging around in your belly button.

We can't even fix the problems on our first planet. How (and why) can we even begin to think about another one?

There’s a lot why’s to do that. How is the question.

I guess if we do develop terraforming technologies I'd rather we test them on Mars first.

We have solved countless problems on our planet. What are "the problems" you are thinking of?

Green house gases emissions and the collapse of biodiversity are two reasonably conservative examples

We have solutions for those problems on Earth, the difficulty is implementing the solutions. And that's a political and sociological problem, not an engineering and logistics problem. The engineers and logistics people can work on Mars while the politicians and sociologists work on Earth.

(Not to mention that solving Mars problems are likely to yield novel solutions to Earth problems, ones which we might never discover without thinking about things with an unusual perspective.)

Given the radical changes that a carbon neutral and eco-friendly modern civilisation would require, reducing that to technical problems in each field is really not helpful. By and large we know how a sustainable society could work, we are simply unable to implement it at the right scale. I wouldn't call that "solved".

Your second sentence is correct and invalidates your first sentence. We don't need any "radical changes," we only need to implement existing solutions at the right scale. Once we have enough solar panels, wind turbines and battery cells, a tipping point is reached where the cost of renewable energy plummets so hard that fossil fuel energy becomes catastrophically uneconomical. Economics will take care of the "radical change."

These existing solutions are already on an exponential growth curve and cost decline. They have been for ages. We're on the right path right now; sadly most people find it difficult to see ahead beyond linear growth.

---

[To be clear, here I am responding to the challenge of bringing greenhouse gases emissions to a level which ends the rise of global CO2. It's a solved problem with lag time. The collapse of biodiversity is the political and sociological problem I referred to in a previous post.]

> We don't need any "radical changes," we only need to implement existing solutions at the right scale

Scale is the problem.

> Once we have enough solar panels, wind turbines and battery cells, a tipping point is reached where the cost of renewable energy plummets so hard that fossil fuel energy becomes catastrophically uneconomical

The radical change I'm referring to is the drastic cut in energy consumption to make renewables work at our current scale. I suggest you have a look at the latest IPCC report [0]: we won't be carbon neutral without reducing our energy consumption, not "simply" replacing a source by another for each use, reducing it. That means doing less things, which no one plans on doing.

Not even to mention that some non negligible parts of our economy don't have a technical solution yet, the aviation industry for instance.

> a solved problem with lag time

I don't understand what you mean by that as it seems we are not on the right trajectory to avoid a catastrophic outcome...

[0] https://www.ipcc.ch/report/sixth-assessment-report-cycle/

> The radical change I'm referring to is the drastic cut in energy consumption to make renewables work at our current scale.

Unnecessary. You’re thinking linearly. We don’t need to cut energy consumption, it will be met and exceeded by the current exponential growth of renewables and storage. The “we have to do less” crowd are wrong and bad at math.

Aviation isn’t a solved problem yet but that’s still less than 3 percent of fossil fuel sourced greenhouse gas emissions. There are far more pressing concerns like banning domestic fireplaces.

I would be more concerned about the ocean shipping industry, one which is just screaming out for nuclearisation, but of course that would be protested by ignorant faux-environmentalists who care more about telling others what to do than what’s actually good for the planet. (For some light entertainment, read up about fractional distillation and learn about exactly what it is most cargo ships burn. It ain’t avgas, that’s for sure. But nobody cares because intercontinental trade doesn’t work as well as commercial aviation as a target for class warfare.)

> That means doing less things, which no one plans on doing.

No one plans on doing that right now. But once we divert the attention of astrochemists away from studying the terraforming of Mars and towards the intersection of politics and sociology, I’m sure they’ll come up with the solution.

> it seems we are not on the right trajectory

It would seem that way if you think linearly.

> The “we have to do less” crowd are wrong and bad at math.

Physics, not maths. You can sustain exponential growth as much as you want without physical limits. If that's where your confusion comes from, you can read some vintage Meadows.

> It would seem that way if you think linearly.

Even the optimistic scenarii put us in a bad position... ignore evidence as much as you want, it won't make it true.

Maths, not physics. They're thinking linearly when the curve is exponential.

I can think of a few: Petroleum replaced whale hunting, cars replaced horses pooping on streets, we finally eliminated lead in gasoline, we significantly reduced acid rain (NOx and SOx), we eliminated CFCs once they were shown to damage the ozone layer.

> We can't even fix the problems on our first planet. How (and why) can we even begin to think about another one?

For precisely this reason?

We can't stop asteroid impacts. We can't stop a well-adapted plague, either (Ref: Covidiots). We have dictators with nuclear weapons that we can't stop. etc.

Having a self-sufficient colony somewhere other than Terra is almost certainly the first step toward avoiding a "Great Filter" event.

> We can't even fix the problems on our first planet. How (and why) can we even begin to think about another one?

By this logic we never go. There will always be giant seemingly insurmountable problems. If we solve climate change there will just be another, and another, and another. Life is a never ending fight against entropy. There will never be a time when we have it all figured out.

Secondly it’s entirely possible that the stuff we learn trying to survive off world will be applicable to making life here more sustainable. It could force us to figure out how to run industry efficiently with a very high percentage of material recycled, and how to run an economy without a lot of low entropy ecosystem to draw from. Also no fossil fuel. They don’t exist. We’d only have nuclear and solar really.

Because life deserves redundancy?

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

People build bridges today that are expected to still be standing in 100 years.

They could have made it a bit weaker, not bothered with paint or inspection hatches, and saved a little money, and had it only last 25 years...

The time-value of money says that any benefit 25+ years from now is almost worthless, so it probably wasn't worth spending anything on those things to make the bridge last longer.

Yet in most cases we still tend to build it to last 100 years, despite the economist saying it isn't worth it.

Probably not the best example since once a bridge is built you can immediately use it, the benefits don't only start rolling in after a 100 years. Making sure something lasts is correlated with natural disaster safety margins anyway so if it has to be built to survive near term extremes it'll generally also survive a while as a side effect. Older constructions also seemingly last longer through survivorship bias and the lack of computer modelling at the time meant that safety margins had to be higher.

A better example are maybe tree avenues that take decades to grow into anything useful, or maybe long term river redirection projects or reactors. ITER's still in construction after 16 years. But there's just about nothing we do that would take more than a few decades to start showing returns.

I'm not sure what the rules are in the US but in Australia the infrastructure service life is set by regulation. It's not an economic / financial argument or even a benevolence / moral argument that causes this, it's a legal requirement. There are significant real world advantages of having a bridge last more than 25 years that are not reflected by a financial return on investment.

I don’t think we really have most bridges built to last 100 years. What I see most is built to last 50 years and then usually it is stretched by patching/fixes or ignoring the issues as those will be passed on to whoever is in charge politically when a bridge finally fails.

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

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.

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.

Your last paragraph is an excellent point that highlights the likely risk factor by using existing infrastructure as an example.

Skyscraper are not a good or a primary target. Why bother with a tower if the same number of people can be hit easier on a surface - a demonstration, Sunday market, transportation hub etc. Also I suspect that a lot of conventional explosives is needed to topple one, and it also requires to have a specific faults. You need at least half a ton of explosives to maybe do something (basing on the amounts russia uses in their ballistic missiles against cities), and that is not guaranteed.

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

an object in motion stays in motion

and inertia is a bitch

you have to choose to hit something, because the energy to completely eject that mass from being dangerous would be a lot

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.

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

Do you have any evidence to back this up? It seems like it was the SV's dream in the nineties, yet so far it failed. Economical and intellectual connections doesn't seem to prevent us from being divided and ultimately waging war...

What does this even mean? What is your definition of truly connected?

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.

Fusion bomb is technologically hard problem even today. Fission is simple but required a of the material which can only be produced by technologically hard devices. This gates it for now. But even today we can see that countries wishing to destabilize neighbors can simply gift complete assembly to their allies. Like russia did with North Korea, and is now probably doing with Iran. So ownership of the tech by large political entities doesn't matter if one of such entities decides to defect and abandon common rules.

So, yes, there won't be some independent spacer terror cell. But what if one of the space faring countries will decide to simply sponsor some Hamas 2.0 to attack their opponents? Considering that this will be a new age of conquest possibly, where nothing in the Solar System is yet owned by anyone and there will be a lot of takers. Like a simplest question - who's are Luna and Mars? :)

Next issue is that chemical rockets are much simpler and cheaper, also they are not gated by any tech or material. Sure, there are important secrets around nozzles and stuff, but I suppose a simple crude rocket will work just fine. So assuming we are at the level when humans can travel to the asteroids to mine them (also a big if, due to it being economically unfeasible) they can setup such a kamikaze rocket. Attack will be from outside of the ecliptic plane, so likely undetected. Attack can be scaled to more than one rock, so that every single point of failure, every dome etc must have dozens of anti-spacecraft level defense rockets (nukes most likely). It is not feasible.

Of course all of this is about far far future, we can't predict what will happen.

> Attack will be from outside of the ecliptic plane, so likely undetected.

It won't be. There is no stealth in space, and telescopes are really good. Once there will be a lot of man-made objects in space, it will be trivial for a state actor to continuously track the exact position (and complete history) of every single man-made object large enough to have an engine in the solar system, and I would assume that everyone with major space interests would do that.

There is no stealth in space, but space is also very large.

"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.

While they are not ICBM, the mid range, nuke capable, ballistic missiles are used daily against Ukraine and Israel cities. Imagine that these two countries had domed cities on Mars. Even a single rocket would kill whole population immediately.

The small dingy rockets fired by Hamas are utterly incomparable to ICBMs. It's not the same thing at all. Theoretically almost everything is "nuke capable" and that means nothing in this context.

You were talking about the "total destruction" of the ecosystem on Earth, because "throwing space rocks" will be "trivial for any terrorist cell". Talk about hypothetical rockets fired on hypothetical domes on a hypothetical Mars colony bears absolutely zero relation to that.

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?

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.

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

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.

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).

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.

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

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.

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.

They probably are not 2 dimensional

Take your well achtually’s back to Reddit, dude.

You have nested shells in a sphere. Like a couch on moving day, there are only so many shapes that will fit around a corner and still be substantial. If they weren’t substantial no reasonable person would call it a chunk the size of Africa.

Or just google it.

> Take your well achtually’s back to Reddit, dude.

I guess you're somehow convinced that such an infallibly good explainer that any question for clarification must come in bad faith.

> Like a couch on moving day, there are only so many shapes that will fit around a corner and still be substantial.

That defines the geometry perfectly, glad you explained it so clearly.

> Or just google it.

Yeah, why waste time reading your comments.

No, I'm convinced that some people are blaming people commenting from their cellphone for not spoon feeding them the entire story when they could spend the same energy on extrapolating for themselves.

This sort of learned helplessness didn't help you in school, and it certainly doesn't help you professionally.

Also, "Whatever <move on to another topic that interests you more>" is a perfectly valid response. 90% of the time only narcissists care about ambivalence.

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

A rather dramatic answer to the question of why life on earth started 'recently'. I wonder how long it took that chaos to settle back down.

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.

The major force keeping our core hot is nuclear fission.

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

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

Here's a survey paper with a deeper treatment of the topic, for Earth and other solar system bodies:

https://link.springer.com/article/10.1007/s11214-020-00656-z

"On the Distribution and Variation of Radioactive Heat Producing Elements Within Meteorites, the Earth, and Planets"

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.

Well, yes, but it basically means the core is wrapped in a heat-producing blanket (the rest of the Earth), so we can say that the fissile materials on the outer parts of the Earth does keep the core stay warm.

That's what my physics instincts tell me. It might take centuries for heat to conduct across the planet interior, but it has nowhere else to go.

I'm open to being told my instructions are wrong in this case though.

I wouldn't say that the best way of thinking about it is the blanket analogy because conduction is _not_ the primary way that the earth sheds heat, convection in the mantle is.

Though I haven't run the numbers, I would strongly bet that the core would be _hotter_ than it is right now if the mantle did not have internal heating.

The reason being that, the rate at which you remove heat from the core (e.g. the rate at which the core cools) is entirely determined by the rate at which mantle convection removes heat. Radiogenic heat is a _strong_ driver of mantle convection in the earth, without radiogenic isotopes you would get much more sluggish mantle convection and a much lower rate of heat removal from the core.

The reason for this is twofold:

- Internal heating leads to higher temperatures which leads to lower viscosity and more vigorous mantle convection - Internal heating will locally heat cold "blobs" and make the buoyant

I would also (much less strongly) bet that plate tectonics would not occur without internal heating. We only see plate tectonics in a narrow slice or parameter space in mantle convection models and once you get plate tectonics you get _much_ more heat removal and _much_ faster cooling.

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).

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.

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

> 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?

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.

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.

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.

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

It's an option for terraforming Mars.

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.

Human capacity and human will are, however, rarely aligned. Many great things we can do with collective efforts, but this is not our society.

I think will is pretty aligned, unfortunately.

There’s a pretty good series called For All Mankind about an alt history where all our Cold War military spending went to space instead. We are going to Mars in the 90s. It’s plausible.

Not that many people care about exploring the universe. Far more care about squabbling over little bits of dirt on Earth.

What would power it?

You have 24/7 solar power in space

The energy requirements to generate a large enough magnetic field to shield an entire planet from radiation is many orders of magnitude higher than any reactor we already have on this planet can produce, let alone from solar power, and let alone the energy requirements from cooling, etc. In other words, this is science fiction. It isn’t something we even know we could do.

Terraforming planets is science fiction. We’re a long ways from there. We don’t even have industry in space yet.

Terraforming it to our liking is a long way off. But it might be easy to accidentally terraform something. Microorganisms are shockingly creative at survival.

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.

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

Heh. What radio?

Let's say that we would need an alternative to Internet by then.

In a world where long distance electronic communication is no longer possible, packets of data must be delivered physically from place to place.

The people who deliver these packets still go by the name…

Courier.

I, for one, wish we'd go back to physical storage media such as DVDs, Blue-Rays and CDs.

It made you value the content so much more.

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.

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

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.

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.

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...

Thanks for the link -- I hadn't seen that. My issue is that water lost faster than delivered by comets is bad for tectonics, which is bad for atmospheric CO2. They'd have to show no net loss of water, or else the system is not stable over Gyr timescales.

> 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.

In 1860 atmospheric co2 was at 288 ppm [0]. By 1960 it was around 317 ppm [1]. A difference of 29 ppm which works out to about 226.78 gigatons of co2 [2].

In 2022 we emitted 37.5 gigatons of co2, up 0.9% from 2021 [3]. We are currently emitting an "industrial revolution" of co2 every ~6 years.

[0]: https://www.chicagotribune.com/news/ct-xpm-2000-05-23-000523...

[1]: https://www.statista.com/statistics/1091926/atmospheric-conc...

[2]: https://www.quora.com/How-many-grams-of-CO2-are-in-the-atmos...

[3] https://www.statista.com/statistics/276629/global-co2-emissi...

Consulting Wikipedia, I guess I'm talking about "Industrial Revolutions Units" then.

Is this a real thing? I can't find anything about it on wikipedia.

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)

But for some reason people still want to live there?

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

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.

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

That's a whole human history

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.

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

I think the proponents here are imagining a future a few hundred years from now where we have done that and there are 10s of billions of people in the solar system on multiple planets.

The point is trying to get past the Great Filter. Humanity faces threats from the cosmos beyond the ones we create on this planet.

We can do both: work to repair our planet while preparing for colonies on another.

The Great Filter is not likely an astroid or gamma ray burst type phenomena but rather the nature of intelligence that evolves in a competitive environment via evolution. Having two planets full of hyper competitive, violent social apes just means having two planets plagued by petty infighting. And if one planet is insane enough to nuke itself, what's to say it won't nuke the other?

If humans have a big enough presence on a second planet for there to be wars, we’ve almost certainly spread throughout the rest of the solar system and potentially have even put generation ships en route to other star systems, so even if earth and mars are nuking each other humanity will persist.

That scenario is somewhat unlikely anyway simply because access to resources is so much greater at that point, with there being thousands of times more of anything we have on earth in the asteroid belt and other parts of the solar system.

Isn’t it also very human to fight over control over those resources?

When supply is short enough to warrant it and control is a realistic possibility, sure. Even if humans mastered spacefaring tomorrow neither would be true for many centuries. The scales involved are utterly unfathomable.

Spoken like a true inyalowda. Maybe we skip the nukes and just send some rocks, sasa ke?

War is typically fought over limited resources. Getting to the proposed step would imply we have a handle on our inner solar system: https://hir.harvard.edu/economics-of-the-stars/

>War is typically fought over limited resource

Citation needed

The wars we've seen most recently have nothing to do with limited resources. Most wars through history have been about ego/ambition of royal assholes, and hatred/religious differences. Neither world war was about limited resources.

>"Most wars are not fought for reasons of security or material interests, but instead reflect a nation’s ‘spirit’"

https://blogs.lse.ac.uk/europpblog/2013/07/16/most-wars-are-...

While it is possible future wars might be fought over limited resources, that hasn't really been the main factor in most wars that we know of dating back at least 1000 years.

Interesting. Something like 'spirit' is tough to define. WWII could be categorized as a nation's spirit and revenge, but would Hitler had been able to whip up the nationalism required if Germany had been overflowing with resources and was prosperous?

Germany had plenty of resources to assault most of Europe. The resources they did have could have been used for good, but they chose to exterminate millions, and then tried to hide the evidence. They attacked every country around them because of twisted ambition and their corrupt fascist ideology. They were most certainly not correct in suggesting that it was the Jews and gays and everyone they didn't like that was the cause of any problems within Germany. They demonized "the other" to gain support for making war.

This planet has a clock that is running out.

If left to itself, even if humans never evolved on this planet, Earth dies in roughly 500m years. A complete total extinction event, as the carbon cycles break down and life on earth slowly starves.

More than 75% of the time life gets to enjoy on this planet is behind us.

500m years seems like a long time. It is not. 75% of life has passed us by, and we have only a single species so far that looks like it might be printing a golden ticket to get life off this rock. If this exercise fails, either another species rises to the calling (squids maybe? Idk), or everything goes extinct.

Human intervention on this planet is necessary. And getting life off this planet is necessary.

Advocating for anything else is advocating for letting all life on earth die.

*Citations very much needed to pretty much everything you just said.

Exact numbers vary… but I think it safe to say no matter what, it’s beyond our capabilities to understand. Either way, eventually the “sun goes boom” and we need to be long gone, or dead, as a species.

https://en.m.wikipedia.org/wiki/Timeline_of_the_far_future

A good entrance to the rabbit hole.

> 500m years seems like a long time. It is not.

I mean...talking about timelines like that is difficult because of the way we perceive time, I think most people can't have any reasonable discussion about something that far out. If we try to make it more comprehensible by saying humans have existed for 200k years and have 500m before Earth is uninhabitable, humanity is the equivalent of 12 days old in the scope of an 85 year life expectancy. We're newborns in diapers drinking milk, thinking about what kind of inheritance we'll leave for our great grandkids.

> We're newborns in diapers drinking milk, thinking about what kind of inheritance we'll leave for our great grandkids.

I know, aren't humans awesome?

Most species just eat all the corn and die, or convert the atmosphere oxygen causing a mass extinction.

Humans are looking up and going "oh wait, we are causing a problem, how do we solve this?" and then they follow it up with "and even if we solve it, we need to do something about the whole carbon cycle thing ending, how do we get life off this rock?"

I don't know of any other species that has gotten anywhere close to this.

Humans are great.

It’s not an either/or choice, we should do both, if only because learnings from performing planetary engineering on Mars will benefit similar efforts on Earth, but also because there’s no point in pigeonholing ourselves into a single planet. We’re cavepeople to Earth’s metaphorical cave and it would be wise to venture beyond it to become a true spacefaring civilization.

I wish I had more upvotes to give you.

We have the people and resources to to this, and the payoff is literally astronomical.

A big question would be how to divvy everything up.

Why is it always the same argument with you people? They’re not mutually exclusive. We must save our planet and we must terraform other planets.

Why backup your harddrive? - it's cheaper to just use the one you already have. There is no point.

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.

You would split it to o2 and carbon. The real issue is the rotation speed of venus. Almost a year to rotate arround its axis.

What do you do with a 95% oxygen atmosphere with now only ~60 times the mass of Earth's atmopshere? You could make a small ocean out of it, but that's a huge amount of H to source.

We need to somehow get it to Mars.

That would be useful for about 1-2% of it; but it would be better to bring it to Mars as CO2 in the first place and crazy expensive. I like the idea, though. Maybe space habitats around Venus instead.

I've often wondered if it would be possible to spin Venus faster to shorten its day. Possibly by firing millions of large asteroids past Venus at just the right angle.

Added bonus is that you can mash all those asteroids together to give Venus an Earthlike moon.

Plus I wonder how such large scale gravitational engineering would affect the rest of the solar system.

About 323 million times the energy humanity produces in a year to spin up Venus [0] so probably not anytime soon.

[0]: https://nathanielmrouth.wordpress.com/2021/04/30/what-would-...

Thank you for a super interesting link!

It briefly mentioned the equatorial bulge that other, faster spinning, planets possess. Would it greatly damage the planet to spin it up?

I also didn't know that Venus' rotational energy is so low that we "could" actually spin it the correct way without spending much more energy.

You would be bombarded with radiation without a magnetosphere

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.

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.

Building a disc to shadow venus is possible today. I don't think we currently have the ability to create the organisms you describe.

>Building a disc to shadow venus is possible today.

News to me.

Just ignoring all the reasons this seems unlikely. Wouldn’t it be constantly pushed away from the sun towards Venus?

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.

Bulletproof but not a vulcanoproof solution.

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

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

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

Water

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

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"

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

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

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.

> 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

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.

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.

    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).

You're ignoring the possibility that the parent commenter is part of a secret time traveling cabal.

This sort of moralizing is counterproductive, wrong, and dripping with irony when you talk about shutting down discussion.

"Idea is only a theory," when talking about science is almost always a misunderstanding of the word theory and a conflation with the words hypothesis or hunch or guess.

Mars previously having a magnetic field isn't dogma. It's the best explanation we have for the evidence. It is knowledge. Dissent is more than welcome if it can offer new evidence, prove why the existing explanation is wrong, or better explain the existing evidence. Until then, it is much more correct to say "Mars had" than "Mars didn't have". "It seems" undersells it and is pointless hedging akin to saying "It seems species change over time in response to environmental pressures due to natural selection."

> (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).

Because you're not an irrational loon? Who do you know who has never been certain and wrong about anything?

In the case of science, look at the evidence. No one is asking you to believe the boy who cried wolf when he tells you the sky is made of marshmallow.

I'd actually posit that this sort of post shuts down discussion even more.

It doesn't provide any sort of useful information that complements or refutes the point in question.

It's useless naval-gazing that doesn't actually actually add anything to the conversation-- as there is nothing that we perceive directly, and anyone seriously discussing it should know the limitations of inference.

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

Humans?

Hypothesis, not theory. FFS...

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)

No. Learn2Science.

In this context, this isn't the semantic hill you want to die on.

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