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Life on Europa vs. Jupiter's Electromagnetic field

  1. Dec 20, 2011 #1
    Hello everyone,

    First to preface I am not a scientist and have the heart of one (I purchased the heart from eBay... jk).

    Anyway I have a lingering question regarding Europa:

    Ok, I get the science about the tidal forces on Europa that flexes the rocky portion of Europa heating up the water and creating liquid middle and frozen outer layers. The theory is that there are thermal vents that may harbor life. But here is my question, from what I have "heard" the magnetic fields of Jupiter is so strong that probes that are sent there has to deal with radiation that could be lethal. So even though there is a liquid ocean, could the same magnetic field sterilize the life on Europa?
  2. jcsd
  3. Dec 20, 2011 #2
    Sure, they could. In the context though you are thinking about life that originated on Earth. Life that originated at the cellular level in an environment with such magnetic fields could easily evolve and adapt to them.
  4. Dec 20, 2011 #3
    Just to add to this:

    Many migratory birds on Earth evolve with a "compass" which functions as a direct result of a magnetic field. It would not be a huge stretch to say that any abiogenesis under highly magnetised/irradiated environments would respond similarly.

    To clarify I find it highly likely that life at a cellular level could survive - there are even Earth organisms that could probably withstand life on Europa. (I am referring to Tardigrades which have now been proven capable of surviving direct contact with the vacuum of space.)

    Hope this helps.
  5. Dec 20, 2011 #4
    Got it thank you for the replies. Now that I think of it, what if there is some type of organism that develops that uses the magnetic field like how a electric motor. Imagine a microscopic piece of magnetic piston. As the creature/microbe position themselves in the field the piece of magnet vibrates creating heat, energy of a sort, or even propulsion? Nice!
  6. Dec 20, 2011 #5
    It does help, thank you.
  7. Dec 20, 2011 #6
    I see no reason why you could not have a microbial organism "powered" by a magnetic field - given the right route to evolution. :smile:
  8. Dec 20, 2011 #7


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    I don't think the danger is from the magnetic fields directly. Magnetic fields themselves are not really harmful. The problem for spacecraft in the vicinity of Europa is that the large magnetic field traps charged particles, so that a spacecraft in the vicinity of Europa sees a large flux of particle radiation, which can damage the spacecraft. This is like the Van Allen belts on Earth, where charged particles are trapped by the Earth's magnetic field.

    However, the charged particles would be stopped by the surface ice on Europa, so I think any hypothetical life in an ocean under the surface ice would not see the charged particle radiation, and so should not be harmed.
  9. Dec 20, 2011 #8
    Short answer is "no".

    Longer answer is, as another poster has mentioned, is that the danger isn't from the magnetic fields, but from the high-energy particles trapped by the fields. Earth's Van Allen Belts are dangerous for the same reason, though the Earth's energetic particles come from cosmic rays hitting the atmosphere and not from the Sun, as is the case for most of Jupiter's trapped particles. Jupiter's trapped particles are accelerated to lethal speeds by its field, so indirectly the fields are the cause & trap of the lethal radiation, but the magnetic field by itself is too weak to be hostile to life. A metre of ice on Europa is enough to protect against the particles, so life beneath the ice isn't threatened at all. In fact the bath of particle energy helps break up the ice into oxygen which is carried into the sub-surface by solid-state convection and impact over-turn.
  10. Dec 20, 2011 #9
    Ah, that is cool. So the ice will protect them. Now "Cosmo Novice" did mention about Tardigrades, according to some sites (including Wikipedia, not that it's reliable) has stated they can survive radiation of quite letal dosage. How can we be sure that when we send a probe there, non of these critters will go with the probe, it sounds like a daunting task to eliminate all bacteria and Tardigrades.
  11. Dec 20, 2011 #10
    Planetary protection is very challenging indeed. But not really a physics issue per se.
  12. Dec 21, 2011 #11
    Very rar i disagree with your posts graall: Astro and xenobiology are very much a part of physics in my opinion. They are crucial in ensuring any protected environments in space remain free from external influence.

    Imaging introducing a native earth bacterium into an alien environment which then subsumes and destroys the entire ecology!!
  13. Dec 22, 2011 #12
    Jupiter's magnetic field is no problem -- it's around 4 gauss on the planet's surface at the planet's equator, and it will be much less at Europa. It should be easy to estimate how much by approximating Jupiter's magnetic field as a magnetic dipole.

    The big problem is Jupiter's magnetosphere. From Page with radiation doses at Jupiter's satellites:
    100 rem = 1 sievert

    We would die in a few days, or at most a week.

    However, some organisms can easily survive such doses, like some bacteria. The champion is Deinococcus radiodurans at 5000 gray (1 gray = 1 sievert for some radiation types). This organism does it by having multiple copies of its genome and using them to rapidly repair damage. This is likely an adaptation for surviving dryness without going into a dormant state; dryness can have similar effects on genomes.

    Large, long-lived multicelled organisms may not be able to come close to that bacterium's performance, however.

    However, Europa's liquid water is most likely underground; its surface is too cold for water to be liquid. Europa's surface is covered with water ice, but there are numerous, divergent estimates of its thickness: The great thickness debate. These vary from about 100 m to over 30 km. Even with the thinnest estimate, it is more than enough to stop Jupiter's magnetosphere particles.

    So Europan organisms will be safe.
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