This is incredibly exciting but a few important details are missing.<p>The first is how big does the structure need to be? I can buy a 1 Tesla magnet online right now but that's probably not what they're thinking of. Would we need a city-sized coil or something like that?<p>The second is the time scale. They say that the temperature could rise by 4 Celsius and trigger a greenhouse effect, but is that an immediate effect (10 years or so) or century-scale effect? I'm hoping the scientists put out a paper because I'd love to learn more about the specifics of their proposal.
"can generate a magnetic dipole field at a level of perhaps 1 or 2 Tesla (or 10,000 to 20,000 Gauss)"<p>I'm just amused by this conversion. Who is this for? Are there people who know one unit of magnetic flux and not the other?
Is there a good entry-level article or video explaining planetary magnetics? I'm an aerospace engineer and I struggle with the difference between magnetospheres, magnetotails, magnetosheaths, magnetopauses and Magneto's psychological struggles.
The article and paper lacks any indication of the amount of energy needed to run such a magnetic field. What amount would it take to run it, and what sources of energy would be viable for it?
Does building a magnetosphere for the purposes of protection require an atmosphere, or is it all about capturing and shaping solar wind?<p>If it doesn't require an atmosphere, could this approach be used to build a magnetospher around the moon? It feels like colonizing the moon first is a much easier and more useful problem to tackle. Once we have a moon colony you can crack water to make fuel and then go "where ever" you'd like - other asteroids, or mars. The moon is much closer and easier to get to, though maybe people need the "excitement" that travel to Mars connotates.
I don't know the specifics of solar radiation well enough to say how much power the deflection would require, but there is an easy order of magnitude calculation to figure out how much energy setting up a field that size would require. It's not the same as consumption but it's a start.<p>The energy in a uniform field is very simple to calculate: a sphere with a radius of 6371 km (radius of earth, diameter of mars) and 50,000 nT would store about a 10^18 joules, about 6.5% of US annual electricity consumption. At the extremal 500,000 nT that would be 10^20 joules, around 2x the global electricity consumption.<p>A dipole field would require ~10x more energy, a zetajoule. That's around 2x the global human annual energy consumption, including for heat/transport/industry/etc.
Here's a thought: Could we put one of these at the L1 point of the Earth-Sun system to protect against solar storms? If something like the Carrington Event happened to our current society, it would be absolutely devastating.<p>Bonus: Could we make it big enough to encompass the moon?
Unfortunately this will not work. That isn't to say that the construction, placement, and powering of an artificial magnetosphere at Mars-Sun L1 is infeasible. It can totally be done with today's tech and modest meter scale superconducting rings. Mini-Magnetospheric Plasma Propulsion (M2P2): High Speed Propulsion Sailing the Solar Wind (<a href="http://earthweb.ess.washington.edu/space/M2P2/STAIF2000.PDF" rel="nofollow">http://earthweb.ess.washington.edu/space/M2P2/STAIF2000.PDF</a>) probably represents the core concept. Except instead of trying to go somewhere you stay where you are. The M2P2 paper says a 10cm diameter superconducting coil can divert solar wind in a bubble up to 20 km in diameter. It wouldn't take too much to scale that up.<p>Of course diverting that much solar wind would create a force on the object. In the paper above that force is used to accelerate a craft. It'd be some handful of newtons at 20 km and linearly more to do what this project wants. One way you might get around that is to "lean into" the wind by going down the sun-side of the L1 halo orbit and allowing the force from the diverted solar wind to counter the sun's gravity's acceleration.<p>But for the vast majority of the lost Mar's atmosphere the kinetic energy needed to achieve escape velocity is <i>not</i> from impact with solar wind ions or other solar wind related/magnetic field means. All those hereafter referenced under the umbrella term "jeans escape".<p>Instead the majority of the kinetic energy needed comes from the ejected electrons from the sun's light ionizing the upper atmosphere. That ejected electron has quite a bit and it is distributed to the ions it later interacts with and as those ions interact with others. If there was no solar wind at all the rate of atmospheric loss at Mars would drop but not significantly if the sun still shone upon it.<p>That isn't to say that, having no magnetosphere, Mars (or Venus) does not lose an additional small amount of it's atmosphere to jeans escape mechanisms. But that amount is limited due to the currents created in the upper atmosphere by photoionization creating their own local magnetic field. That creates a bow shock about the ionopause which slows the incoming solar wind down such that it's constituent ions no longer have the energy needed to deliver the boost required for escape. And because of the induced magnetic field other solar wind magnetic field based mechanisms which would pick-up the ions ionized by the sun's light are mitigated.<p>I love the idea of this but it isn't going to make Mars have a decent atmospheric pressure in just some years.<p>On a (much) lighter note, I was thinking if you put these artificial magnetospheres all over the inner system and then coordinated turning them on and off you could "paint" the termination shock surface of the heliosphere with different scales of tubulence in charge density. It'd be a multi-hundred AU wide screen visible only from very far away with sensitive polarimeters (detecting the changes in lines of sight charge density through faraday rotation). Might be a decent way to METI since it'd not require much energy or high angular resolution at the other end.<p><i></i>tldr<i></i>: It's technically and economically feasible. But it doesn't work like suggested for atmospheric protection because almost all the mass loss is from light caused photoionization, not the solar wind (and other Jeans escape mechanisms).
It is unclear what kind of technology are they planning to use for this shield. If it is usual electromagnets, it's unclear where would they take energy from, if superconducting ones than it's unclear that it would be possible to keep them in superconducting state for long.<p>Wish someone more knowledgable about this kind of tech comment on this.
> The current scientific consensus is that, like Earth, Mars once had a magnetic field that protected its atmosphere. Roughly 4.2 billion years ago, this planet's magnetic field suddenly disappeared, which caused Mars' atmosphere to slowly be lost to space.<p>What kind of event could cause the loss of a planet's magnetic field?
I think the science fiction movie "Spaceballs" was head of its time. Planet Druidia had an enclosure to protect its oxygen, but Lord Helmet tried to suck it out with MegaMaid.<p>NASA might have to think about how to counter such threats, possibly from a future and more hostile Earth civilization.<p><a href="https://www.youtube.com/watch?v=lTSWdHY9Ny4" rel="nofollow">https://www.youtube.com/watch?v=lTSWdHY9Ny4</a>
Best idea I've seen in years on space solutions, specially at colonization. No marketing bullshit, just plain science. And it may be the first practical step on terraform a planet before we try to colonize it.<p>"While it might seem like something out of science fiction, it doesn't hurt to crunch the numbers!"<p>Now we need those numbers.
Would a distributed constellation of satellites at L1 work? A bunch of smaller magnetic dipole umbrellas working together.. Easier to repair and replace individual satellites without having the whole system go down.
"As a result, Mars atmosphere would naturally thicken over time, which lead to many new possibilities for human exploration and colonization.." How long would it take though?
It's a nice idea, and it's one I proposed some years ago:<p><a href="http://arachnoid.com/restoring_mars" rel="nofollow">http://arachnoid.com/restoring_mars</a>
I believe this is the workshop referenced, and they do have a LiveStream that you can watch.<p><a href="http://www.hou.usra.edu/meetings/V2050/" rel="nofollow">http://www.hou.usra.edu/meetings/V2050/</a>
Would something like this be viable as part of a geoengineering solution to climate change?<p>E.g. could we partially cancel out earth's magnetic field in order to control atmosphere loss and thereby control the greenhouse gas effect?
> NASA proposes a magnetic shield to protect Mars' atmosphere<p>That's officially called a "deflector", anyone who's seen Star Trek knows.
Instead of terraforming, would it be possible to build a giant glass ceiling over most of the surface? Humans don't really need an entire atmosphere, just a few hundred feet of it.<p>This is still infeasible now, but it seems much easier than terraforming. With robotic labor and automation, it may not even be that expensive.
So let me get this straight - science can't currently beat flipping a coin in terms of predicting the weather more than 2 days in advance, but he can accurately simulate space weather for many years and how it will affect other planets?