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The Flawed Science of "Avatar" (Pt 1): Floating Mountains

One thing that I have found most annoying about the movie Avatar is the chorus of praise for its "scientific accuracy." I don't know of any movie short of Star Trek that has tried so hard to convince its fans that it's based on real science, and fallen so short. So I thought it would be useful to just make an archive showing that the movie is not science-fiction; it's science mixed with fantasy. We'll start with one of the most controversial ideas in Avatar, floating mountains.

One of the most beautiful and memorable images in the movie Avatar is the scene where the characters are flying to a new area on Pandora and fly through what are known as the Hallelujah Mountains, mountains that literally float in mid-air. The mountains remain tethered to the ground by enormous vines, like balloons on strings. Waterfalls pour down the sides, dissipating into thin air.

A lot of people thought the idea of floating mountains was ridiculous, but the producers and science wizards behind the movie provided a carefully crafted explanation. They explained that the mountains are laced with unobtainium which floats in the presence of a magnetic field. They also said that the magnetic field in that area is so powerful that it can support the mountains. That's a good explanation, but it doesn't work. Here's why.

First of all, any magnetic field powerful enough to levitate tons of rock in the air in the form of mountains would have to be incredibly powerful. In the movie, the only effect of the magnetic field is to mess up the instruments of any vehicle that enters it. In reality, the field would be so powerful that it would tear apart any metal-based vehicle that drove through it. In fact, it would be powerful enough to rip the iron molecules out of the blood, killing any living thing that even came near it.

But one of the biggest problems with the scene are the majestic and powerful waterfalls that plunge down the mountains to be blown away into thin air. Great image, except for the obvious question: where is all that water coming from? Like everything else in Avatar, there's a bogus quasi-scientific answer in the semi-official wiki for that, too. It explains that the water condenses, is absorbed by the mountains, and then dumps over the sides again. The problem is that even a very small waterfall can dump hundreds of gallons of water every hour. There's no way that condensation alone could replenish huge floating waterfalls that quickly.

But hey, it looked cool, right?

UPDATE 06/13/10: Another big flaw with the Hallelujah Mountains is that they kind of undermine the motivation for the evil RDA Corporation. They say they need to destroy HomeTree and attack the Na'vi in order to get at the huge amount of unobtainium they live on. Of course, this is a highly dangerous and destructive course of action that will undermine their relationship with the Na'vi and could led to genocide, so it's an action that would have to be taken after exhausting all options. Like, for example, mining the tons of unobtainium that have to be in the Hallelujah mountains. It would be easier to tow the Hallelujah Mountains out of the magnetic field to get them to drop to the ground, then harvest the mountains before declaring war on the Na'vi.

NEXT TIME: The Avatars

What did you think of Avatar's floating mountains?
[Image source: Moviefone]
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  1. 'One thing that I have found most annoying about the movie Avatar is the chorus of praise for its "scientific accuracy."'... my one thing that annoys me to death about this movie is the tired old plot passed off as something we're supposed to be excited about. I mean... really... you know everything that's gonna happen within the first, oh, ten minutes or so.

  2. Yes - they "researched" the plot almost as much as they researched the geology!

  3. My wife and I watched AVATAR and she asked how the mountains floated. I said that its the Unobtainium and magnetic fields. She said it didn't make sense and I condescendingly said I'd explain later. Now I find out its all garbage and she was right. I don't know how she puts up with me. LOL Looking forward to the next part.

  4. Couldn't agree with you more. I could make another series called "The Flawed Plotting of Avatar." But I've come to accept that people don't care about the story. The people who insist the movie is scientifically accurate are the one thing I couldn't put up with anymore.

  5. You didn't think this one true.

    See, where talking about an entirely different planet here.

    If the rotation speed of the planet is significantly higher the weight of objects around equator would be significantly reduced.

    Secondly, rock isn't just rock. They have different weights depending on their composition.

    And when it comes to waterfall? remember the key word:
    different planet. If the atmosphere on Pandora is much denser and if the consecration of water in atmosphere is much higher the rate condensation would be significantly heightened compared to earth.

  6. These are all good points. However, the difference in gravity between the equator and everywhere else would be almost imperceptible, nothing that would effect the mountains. As for condensation, if it was different on Pandora, then that would be true for everything, and it would always be raining, because of cloud cover, and the jungles would be underwater because of all the water that couldn't evaporate.

    Anyway, my explanation for how the mountains float comes directly from the official explanation, and it doesn't say anything about different weights or rates of condensation. Even the part about how the magnetic field would rip the iron out of the blood was an admission that came directly from James Cameron (check the link).

  7. Antigravity ore was an SF concept in (I forgot which) Hyperion or A Fire Upon the Deep.
    Elemental iron is magnetic but ferric ions in hemoglobin should not be.

  8. On the other hand, great movie :D

  9. Ah, but even if James Cameron didn't find a work around docent mean that there isn't.

    Our current rotation speed is about 1500km/h if I remember correctly. So the necessary rotation speed to make a significant difference between equator and

    If the centripetal force where to nullify the gravitational force we would have to spin, about 30000km/h, I would estimate.
    Thats about 20 times our current speed. So the rotational speed necessary to make a significant difference between equator and the poles would be relatively small.

    When it comes to water condensation:

    1. The magnetic field could have strange effect on the water concentration, seeing as how its polar, making water condensation higher near the floating mountains. but I'm no expert so I don't know.

    2. There could be elements contained in the mountains that improve water condensation.

    3. some atomic textures significantly improves water condensation

    4. Pandora is very biologically active, so it may be due some biology that captures and releases water at an enchanted rate.

    5. Perhaps it stores water over longer periods of time, creating basins. Something like our beavers could create dams that they now and then "flushes"

  10. Shut the fuck up is what I think mate!!!!

  11. Nice job debunking Avatar's mysterious Hallelujah Mountain...but they definately were very cool indeed. Thanks dynamic duo. lol

  12. These are good ideas, but again, these are just theories. None of it is in the actual documentation for the movie. As it stands, this doesn't work.

  13. get a life, its a movie!

  14. You guys think too much. All the creators wanted from you was your $7.50 to see the movie. Guess what? They made BANK! Stop complaining about things that don't matter.

  15. From my blog entry on floating things in scifi literature:

    The recent film Avatar featured a range of spectacular floating mountains, claiming that this was possible due to the planet's unusual magnetic field. Well, planetary magnetic fields fan outward at the poles. Any balancing act between gravity and magnetism would be highly unstable, especially while still in the planet's atmosphere. And since the field must weaken as you move farther from the planet, those huge rocks would be lined up in order of size, biggest on the bottom to the smallest up high. So much for the floating stairways. Hey, at least it looked real pretty!

    I hadn't thought about actually calculating the required strength of the field, but it is clear to me that the direction would need to be UP in order to counteract gravity, which is always DOWN. That only happens at the poles as far as we know.

  16. Nicely done! I hadn't even thought of the orientation problem or the weight issues. Mainly because I didn't know about it. Thanks for the contribution, and for letting us know about your article

  17. Like I said in the intro, I wouldn't normally bother with this, but they started it by claiming how accurate it was. If Cameron had just said, "It's just a movie," I would've been fine with it.

  18. Here's a far better explanation as to why the "Hallelujah Mountains"are an impossibility under real physical constraints, extraterrestrial or not. They simply could not form from a geological perspective. If you notice, the floating mountains have clear evidence of bedding / strata which indicate that these mountains are derived from a sedimentary setting. Let's assume that such a depositional basin exists in which the unobtainium can be deposited and accumulate over time, in which it would eventually become lithified (turned to rock). If such a strong magnetic field is or was in place then the detrital unobtainium would be affected immediately and would not have the opportunity in which to settle out and be deposited to eventually form sedimentary rocks. In other words, the detrital unobtainium (weathered from some igneous body and brought to the region of high magnetic field strength) should not have enough time to be deposited in to such large bodies if the magnetic field is strong enough to lift large mountains.
    Even if unobtainium crystallized much in the same fashion salt (halite), or gypsum, or any other evaporate forms, it still cannot account for why the smaller, newly formed, crystals were unaffected by the massive magnetic field yet the massive mountains of sediment were.     

  19. That's an excellent point. Thanks for the insight!

  20. Poking holes in your articleFebruary 23, 2013 at 9:14 PM

    I never understood why this happened until I was told Unobtanium is a room temperature superconductor. Super conductors levitate around megnetic feilds using what's called the Meissner effect. They even lock into place by a feature called quantum locking so the mountains don't float out of the field and fall but rather stay in position. Now as for not being able to lift that weight. I saw a youtube video from the recent Technology Entertainment Design Talks that states that it can lift 70,000 times it's own weight using this principle, so if enough unobtanium is in those hill they would levitate. On a final note I'm very impressed with the level of thought that went into at least this aspect of Avatar. Sources: http://www.youtube.com/watch?v=PXHczjOg06w , http://www.superconductors.org/ , http://james-camerons-avatar.wikia.com/wiki/Unobtanium


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