This Video Will Make You Grateful for the Earth’s Magnetosphere

by Fraser Cain on June 19, 2012

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A newly released video from NASA showcases the space agency’s data visualization skills, as well as the dramatic science behind the Sun’s powerful coronal mass ejections and their interactions with the Earth’s magnetosphere and climate. These ejections stripped the lighter elements away from Venus long ago, leaving the planet with a desolate, hostile environment. But in this animation, you can watch as the particles from the solar wind are redirected around the Earth, keeping us safe – and hydrated.

This video is actually an excerpt from a longer video called Dynamic Earth: Exploring Earth’s Climate Engine, which is playing at the Smithsonian National Air and Space Museum in Washington, D.C; this portion showcases the interaction between the Sun’s solar wind and the Earth’s ocean currents. What’s really amazing about this video is that the underlying data visualizations are based on real satellite observations. The swirling ocean currents were created from real ocean current data.

Still sitting on the fence, finger hovering over the play button, not sure if you should spend a few minutes of your valuable time? You might be interested to know that the video was recently chosen as a “select entry” for the 2012 SIGGRAPH conference, held in Los Angeles on Aug. 5 to 9, 2012. This is the conference where all the film studios showcase their 3D graphics work. A NASA video chosen as a select entry? I like their taste.

About 

Fraser Cain is the publisher of Universe Today. He's also the co-host of Astronomy Cast with Dr. Pamela Gay.

Darnell Clayton June 19, 2012 at 10:22 PM

Makes me glad that I live upon Earth, but it also makes me wonder if terraforming Mars is worth it since it lacks a global magnetic field (although it does boast a large supply of ice and water).

I wonder if a thicker atmosphere could serve as a supplement to a non-existent global magnetic field?

That said thanks for posting the video! I didn’t realize how much of a role our oceans play in maintaining our comfortable climate upon Earth.

gopher652003 June 20, 2012 at 1:47 AM

Indeed an atmosphere does protect the surface from cosmic rays and other radiation. But a magnetic field protects the atmosphere itself. If Earth had never had a magnetic field it would have lost about half its water over the past 4 billion years.

That’s not life killing, but it’s a significant. Of course, Venus is closer to the sun than Earth, so it would have been hit with even more solar radiation, having an even greater effect on the amount of water the planet possesses. (It has nearly no water now due to a combination of no magnetic field and close proximity to the sun.)

Dampe June 20, 2012 at 2:22 AM

No need to worry about that. Humans won’t ever have the technology to terraform an entire planet. :P

Vino June 20, 2012 at 4:08 PM

Actually we are terraforming a planet as we speak….our Earth..just not to make it habitable but dehabitable (hope there is a word like that)!!

Dampe June 21, 2012 at 1:41 AM

I wouldn’t compare the (supposed) impacts humans have on our planet to the terraforming of Mars :D But i assume your comment was made in jest.

Evan Mathias June 20, 2012 at 12:46 PM

One idea was to terraform mars by using many tactical nukes
to begin the process of reactivating the core of mars, freeing water so that millions
of years down the line Mars would become habitable. You can see from this
video how much energy is available to us in space. We could access more of this
energy for our needs, but note that the earth must shield, deflect and reflect
and circulate around the planet to keep this energy in check. An amazing system
we cannot afford to break. Earth is in every way in the right place and time to
be the miracle we have evolved to be able to understand and appreciate.

Torbjörn Larsson June 20, 2012 at 12:46 PM

As I understand it, it has been modeled that superEarths don’t need a magnetic field to hold on to its atmosphere in ordinary cases (as in, not too close to its star/stars).

But as you can see from my longer comment, hydrogen loss is different as it happens so easily.

However, as in so many other cases (atmosphere retention, heat distribution, plate tectonics), superEarths have it a lot easier than our marginally sized terrestrial to be habitable.* They easily get strong magnetic fields from diverse rotations (convection, axis rotation, orbital rotation) applied to a conductive liquid core.
——————–
* This is the one place where the “Rare Earth” religiously motivated idea has it right – it is likely rare that a runt planet such as ours is an abode for life. Most terrestrials are larger and that is lucky: most habitable planets are likely a tad larger and upwards.

lcrowell June 20, 2012 at 4:21 PM

Terraforming ideas are implausible. We might think of there being some huge n-dimensional space or planetscape which describes all possible planetary surface environments. Each planetary environment is in a basin of attraction, or something similar to a potential well. In order to change the configuration of a planetary environment you have to provide a large amount of energy or change the chemical environment to knock a planetary environment out of its basin and then guide it into another basin. I think it is doubtful we will end up doing these things.

There is one planet we are changing however, Earth. With 7 billion of us consuming the planet’s stores of energy and material resources we are changing the environment here. We are increasing the entropy of the environment, which means we are not making it more livable, but less so.
LC

Torbjörn Larsson June 21, 2012 at 1:49 PM

I’m not into terraforming and haven’t run the figures, but as I understand it, it has been established that rather small means suffice. This is supposedly what underlies Stanley-Robinson’s “Red-Green-Blue Mars” series.
The problem with the theoretical dynamical system stability argument is that it supposes that parameters and constraints are unchanged. But they are not, see our own AGW, so the topology of the system is changeable. Valleys can disappear and new ones appear.

As for AGW by the way, I’ll have to nitpick the stated dystopia.

I think it is far from established that “we are not making it more livable”. It is a fuzzy question in the first place, since life itself waste geological resources and produce massive amounts of waste like carbonate and sulfate sediments, and we compare society lifetime with geological time. The easiest quantifiable question is, is our society making the geosphere and biosphere relatively less habitable over geological time.

I can’t see how. The AGW will mean a temporary productivity loss at worst. But if the system tips and we get out of the ice ages the biosphere will become more habitable (as in more productive), and the ice erosion during expansion and retreat will diminish and leave more mineral resources in general. (Gravel and sand for society can still be found by increased local erosion elsewhere.)

Temporary as in “over geological time”. If it takes the usual ~ 1 million years for species diversity to recover, likely humans will be gone by then. Mammals persist for a few million years, but we evolve much faster than average thanks to our large population size. But since the large Permian extinction, for some reason or other extinctions have meant more diversity after recovery. Again improving on the biosphere.

Something similar happened during the oxygenation of the atmosphere. This environmental catastrophe, perhaps induced by life, happened on a scale we can likely never repeat, not even by a global nuclear war. Maybe that was what finally killed off the cellular remains of the RNA world, they couldn’t cope with remaking their metabolism as well as DNA cells could with their larger genome.

But after it, the poisonous oxygen waste turned out to be a great oxidation resource. Making the biosphere more productive but also expanding in scope everywhere, but especially on land and in air.

I don’t recommend changing the environment for moral reasons (human suffering), but it isn’t the end of the world, just the end of the world as we know it. And in many or most cases it has turned out better afterwards despite what one may think. Probably because life adapts well, and seem to get better at it as biosphere complexity (diversity) increases.

gopher652003 June 21, 2012 at 2:37 PM

I agree. While the current trend of extinctions (from various causes, like ocean acidification) will have a major short term impact, long term (1 ma +) it will have minimal impact. Humans aren’t doing anything today that hasn’t been done to the ecosystem in the past by mass vulcanism or asteroid impacts.

Long term I’m not concerned. Next 100 years I’m not concerned. The next few thousand could be pretty rough though… but only if we technologically regress. If we continue to advance we shouldn’t have any significant problems, beyond some very short term productivity issues (and (initially) nearly insignificant suffering that will be magnified into significance by existing poverty).

Aqua4U June 20, 2012 at 8:35 PM

I think terraforming Mars into a surface habitable planet is out of the question with current technology. About the closest we could get would be to build cities in lava tubes. IF and when we conquer fusion and can create planetary scale magnetic fields with that energy.. then maybe~

Torbjörn Larsson June 20, 2012 at 12:34 PM

CMEs responsible for atmospheric loss? Likely not.

I haven’t kept on top of the Venus Express data, and it seems hard to get a grasp on, so I’m simply hoping this encyclopedic article is a well rounded update:

“The relative importance of each loss process is a function of planet mass, atmosphere composition, and distance from a star. A common erroneous belief is that the primary non-thermal escape mechanism is atmospheric stripping by a solar wind in the absence of a magnetosphere. [...]

Dominant non-thermal loss processes differ based on the planetary body in discussion. The varying relative significance of each process is based on planetary mass, atmospheric composition, and distance from the Sun. The dominant non-thermal loss processes for Venus and Mars, two terrestrial planets without magnetic fields, are dissimilar. The dominant non-thermal loss process on Mars is pick-up from solar winds, because the atmosphere is not dense enough to shield itself from the winds during peak solar activity.[2] Venus is somewhat shielded from solar winds by merit of a denser atmosphere, and solar pick-up is not the dominant non-thermal loss process on Venus. Smaller bodies without magnetic fields are more likely to suffer from solar winds, because the planet is too small to hold sufficient atmosphere to stop solar winds.

The dominant loss process for Venus is loss through electric force field acceleration. Because electrons are more mobile than other particles, they are more likely to escape from the top of the ionosphere of Venus.[2] As a result, a minor net positive charge can develop. The net positive charge, in turn, creates an electric field that can accelerate other positive charges out of the system. Through this, H+ ions are accelerated beyond escape velocity, causing atmospheric escape through this process. Other important loss processes on Venus are photochemical reactions driven by proximity to the Sun. Photochemical reactions rely on splitting the molecules into constituent atoms, often with a significant portion of kinetic energy maintained in the less massive particle. This particle is of sufficiently low mass and high kinetic energy to escape from Venus. Oxygen, relative to hydrogen, is not of sufficiently low mass to escape through this mechanism on Venus.” [My bold]

I tried to get to the Venus Express data, but as of 2008 they gave mostly a question mark to how the observed oxygen, of which ~ 80 % is lost on the night side, is lost. The article leaves that open.

I believe most of Venus oxygen otherwise has been sequestrated into rocks, oxidixing them, which as the article notes have been the main attribution of Earth atmosphere.

Ironically then, it is likely the mostly induced magnetic field on Venus that is responsible for its water loss (since if you loose hydrogen, you loose water).

lcrowell June 20, 2012 at 4:01 PM

I think the thrust of the argument is how the solar wind changed the chemistry of the atmosphere. Hydrogen atoms are easy to fling out into space. Carbon and oxygen are less so. Of course Mercury has no atmosphere to speak of, and solar wind could well have stripped off an early atmosphere it might have had.

LC

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Torbjörn Larsson June 21, 2012 at 1:18 PM

Yes, but for dense atmospheres solar wind means less as per the article.

Mind, I think Venus Express or some other orbiter has to deliver the ground truth.

Aqua4U June 20, 2012 at 8:30 PM

DEFINITELY high end criteria for other habitable planets? MUST HAVE a magnetosphere!

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