Solar Wind Rips Up Martian Atmosphere

IHateEverybody writes "Scientists have found evidence that the solar wind is ripping off chunks of the Martian atmosphere, which could possibly explain why Mars has such a thin atmosphere today. The chunks are being ripped up along 'magnetic umbrellas,' which are bubbles of magnetic fields which rise from the ground and extend above the Martian atmosphere. This is surprising because scientists previously thought that these magnetic umbrellas protected the Martian atmosphere. Now it looks like exactly the opposite might be true."

Comments

bad news for earth?

[Bizzeh]

if this is possible on mars, what different properties does earth have to stop our atmosphear from one day just disapearing?

Re:bad news for earth?

[WindBourne]

I would say that you are correct. The article is saying that the SMALL LIMITED mag fields on Mars allows, even encourages, the ripping. Our field encompasses the entire planet and prevents. I have wondered if the moon acting on our core is what makes it spin. As such, it would seem that pushing a large asteroid (perhaps ceres) around Mars would re-start its core spinning. Of course, that tech is out of our reach for a while, and we do not have enough data to know if something like that would work.

Re:bad news for earth?

[hvm2hvm]

There is a small loss of atmosphere anyway from other factors. Still, the atmosphere is slowly regenerated by the combination of gaseous emissions (like from volcanoes) and their conversion to life sustaining gases by low order life forms (plankton or something like that). Those emissions are slowing down because the Earth is cooling down but the loss of atmosphere (by natural causes) is way beyond our foreseeable future (maybe more than the lifespan of the Earth).

Re:bad news for earth?

[Tablizer]

Venus is roughly the same size as the Earth. However, it has no intrinsic magnetic field.

Oddly, Venus' atmosphere is much thicker than ours. Although it has a molten core, it still has a very weak magnetic field. The leading theory is that Earth's magnetic field is somehow helped by plate tectonics, which generally doesn't happen on Venus. Plate tectonics may help molten fluids circulate to help run the magnetic dynamo. A lessor theory is that our moon plays a role. It may be a combo. It's still an open issue.
       

Re:bad news for earth?

[Ambitwistor]

A factor contributing to its weak magnetic field is probably that Venus rotates very slowly (its day is 243 earth days).

Re:bad news for earth?

[DavidKlemke]

It might also be worth mentioning that Venus' rotation is also retrograde:

http://en.wikipedia.org/wiki/Venus
http://en.wikipedia.org/wiki/Retrograde_motion

Now this might not be a factor in itself but whatever caused Venus to spin slowly in the opposite direction to everything else in the solar system probably had some effect on its magnetic field as well.

Re:bad news for earth?

[Power_Pentode]

Plate tectonics may help molten fluids circulate to help run the magnetic dynamo. A lessor theory is that our moon plays a role. It may be a combo. It's still an open issue

I've always suspected that the Earth's strong dynamo was due to the differential rotational speed of core and the crust - caused by the Moon continually slowing down the crust from tidal forces. This continual stirring also results in plate tectonics. That's my theory and I'm sticking to it :)

at least...

[Pharago]

at least we may know what to fix if we *ever* were to terraform that big red rock

Depends on how large a field you want.

[jd]

People are exposed to 2.5 tesla magnetic fields in conventional MRIs, and there are MRIs that go up to 9.3 tesla (even though that's a bit beyond what the FDA approves). There are scanners for animals that go up to 12 tesla. Even the least of these is well beyond anything the Earth generates. Clearly, however, magnetic fields are not as dangerous as has been assumed. At least, within reasonable limits.

This is a localized magnetic field, however. If you were to set up a Faraday cage, so that you were enclosed in a uniform magnetic field, you shouldn't ever detect it. A totally uniform field has zero effect on anything inside that region of uniformity. This would offer some interesting possibilities, as it would be a great deal cheaper to rig up a Faraday cage of some given internal volume than a totally pressurized dome of equal internal volume. The rest of the air would be breathable, and short exposure to the localized fields outside should be no more hazardous than short exposure to the magnetic fields in an MRI, and simpler forms of life (plants, for example) should be safe enough, allowing you to place the terraforming mechanism outside the inhabitable zone.

There is another option, however. It is radioactive material that keeps the Earth's core as hot as it is. We have plenty of such material we desperately want to get rid of. Provided you could find a method of getting the nuclear waste into the Martial core, there should be more than enough by now to strengthen and stabilize the natural magnetic field to usable levels for longer than we'd ever care about. Getting it there would be a problem and a half - mechanical drilling would be impossible and relying on maintaining a sub-critical mass to achieve the "China Syndrome" long enough to nuclear drill through would at best risk landing you with a supervolcano in your lap. However, I'm going to call that an "implementation detail" and not worry about it.

Re:but it would have to explain non-magnetic Venus

[largesnike]

Well actually, we know that Venus was catastophically resurfaced a few hundred million years ago, because impact craters are evenly distributed accross the surface (according to the Magellan data), so the parts of the surface are all the same age. The outgassing from such an enormous event, is likely to be the current atmosphere, which the sun has been gradually eroding ever since.