6 comments on “Alien Worlds in SciFi Movies

  1. Jupiter is the only one of the four gas giants in our solar system which has the radiation problem that you mention. Why can’t Polyphemus (the planet in Avatar), be like Saturn or Neptune? That would solve the radiation problem. The only problem I had with the science of Pandora was that it should be tidally locked–like every large gas-giant-orbiting moon in our solar system (I think, don’t quote me on this–there may be some that aren’t, but none pop into my head). If that were the case, then we wouldn’t see majestic veiews of the planet rising and setting like we do in the movie. It would either always be in the sky or never. That would also create some pretty interesting day/night cycles too, I imagine…

  2. While I understand your issues with the movie, I feel that we don’t have an extensive sample size of what large planets may be like. We can not make general assumptions that all gas giants are like Jupiter, with intense magnetic fields and radiation belts. This makes it easier to accept Pandora as depicted.

    I would have bigger concerns with the local flora and fauna wiping out our defenseless immune systems. Not being able to cope with native bacteria, viruses and parasites is probably the most disappointing thing about visiting extra-terrestrial planets – especially one as inviting as Pandora.
    -RC Davison

  3. I don’t disagree with either of you on the points you raise. We don’t know enough about the gas giants discovered so far to know what level of magnetic fields and radiation environments they have, but consider that if you have a gas giant, it probably will likely be structurally similar to Jupiter and Saturn — i.e. layers of conducting material beneath the cloud tops, atmospheric activity (as seen in Pandora’s primary by the giant red spot-like storm) that would interact; and conducting layers would imply magnetic fields — large planets at this level will likely have large, powerful magnetic fields. And, if there’s any source of charged particles, we’ll have a radiation environment. Those particles could come from the star in the system. So, we should, at some level, assume some radiation environment. What it is and how it affects the pandora-like planet remains TBD.

    About Saturn’s magnetosphere: I refer you to the Cassini mission site about it: http://www.esa.int/esaMI/Cassini-Huygens/SEMBJCHHZTD_0.html

    Saturn does have a strong magnetic field and an immense magnetosphere that’s about a fifth of Jupiter’s. It is in some ways more similar to Earth’s, and it does trap radiation belt particles, and these particles reach levels similar to those of the terrestrial magnetosphere. That does imply that any world near a Saturn-like world could be affected, but that would depend on the strength of the field, etc.

    I like the point about the native flora and fauna being a danger to humans. Cameron doesn’t really address that, but it’s interesting that he addresses the CO2 atmosphere and its effect.

  4. Also Pandora’s proximity to its parent planet seem to suggest that it’s close enough that it should experience tidal forces the likes of which Io undergoes in its orbit around Jupiter. So even worse, instead of a lush verdant paradise, we should be seeing a torn and hellish volcanic landscape.

    As pretty it is having Polyphemus hover overhead so close by, there’s no escaping its certain very powerful gravity influence.

  5. Yup. I kind of alluded to that in the posting — and now that I think about it, it’s a good question as to whether or not Pandora could even exist. However, to get Io-like conditions, you also have to have another gravitational influence tugging at the world. In Io’s case, it’s also being tugged on by the gravitational influence of Europa, Ganymede, and Callisto. I don’t recall seeing other worlds around Polyphemus. Even if there are none, you still have to contend with the pull of the larger planet on the smaller world. Perhaps it’s breaking up and that explains those floating mountains — although I seriously doubt that a world breaking up would have any such verdant landcape on both the world and the floating mountains. Another planetary mystery — but great fun to speculate about and even learn a little about planetary science, no?

  6. the planet that your refer to, the one which Pandora (in Avatar) seems to revolve around, could be a dead planet. It may not have a molten core, therefore no magnetic field. Much like how Mars is today.

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