Monday, June 28, 2010

Unobtainium This: Scientific Errors in Avatar

I've quit gauging the science of Hollywood films--or any films, for that matter. I sense that most writers of science fiction films pick up an issue of "Popular Science" for inspiration. They stretch vague generalizations--whose exploitability is already exaggerated--about the nature of space and reality without fully exploring the causes and repercussions of those things.

As a person studying science, I found this irritating for a long time, but I eventually gave up. So long the plots and writing of films engaged me and the rules of the world created were consistent, I suspended my own sense of reality for the time my eyes enjoyed the film. I simply wanted to enjoy what I watched.

When I saw Avatar, I applied this policy. The plot wasn't great, but the visuals were fun. I accepted and joined the collective ride. Then I read this article, which opened with:
"The producer of "Avatar" is fond of saying that writer and director James Cameron does not write science fiction, he writes science fact."

The link is long since dead, but the rage I felt when I first read this was uncontainable... or perhaps, unobtainiumable. Either way, it's boiled beneath my skin for months and erupts here, now:

+ Floating Islands
The article I linked to above first discusses James Cameron's attempt at rationalizing the existence of floating mountains. They're simply not possible--not in the way the movie portrays and not with his explanation.

Cameron claims the mountains float because of superconductivity. He claims that unobtainium--the desired goal of the human colonists in the film--superconducts, and because Pandora is loaded with the stuff, it makes giant floating mountains.

What Cameron is referring to is something called the Meissner Effect. In short, if a magnet is placed near a superconductor and the conditions are right, the magnet can float. This is why unobtainium--when displayed in the office of the stock character "Greedy Corporate Bureaucrat"--is always floating in some kind of little... circle thing, probably a magnet.

This cause for the mountains' levitation would have caused major physical problems. For example, watch this video of the real Meissner Effect:

http://www.youtube.com/watch?v=Be3qiux6Dow
Notice something--the magnet floating above the superconductor spins. This has to do with the way the magnet ends up floating in the first place. Just remember, the floating islands in Avatar were completely stable. None of them did flips or rotate, they stayed pleasantly upright.

It's not just that the islands were too stable to be supported by the Meissner Effect; they lacked its most fundamental aspect--the magnetic field. One of the fundamental properties of a magnetic field is that wherever there is a changing magnetic field, an electric current is induced. Even the Earth's magnetic field induces small currents in boats as they move throughout the globe.

The Earth's magnetic field is relatively weak--assuredly, it doesn't make islands float. If the islands in Avatar were held up by magnetism, any ship passing through would experience powerful induced currents in the hull of the ship. These currents would wreak havoc on the ship's on-board electronics, not to mention the hull itself. The currents have to discard their voltage somewhere; it would go right into the hull, causing the ships to heat up and explode.

I didn't see anything like that.

+ Large-scale Bioluminescence on Pandora is Improbable.
Bioluminescence is the production of light by organisms. Lightning bugs, of course, produce some light, but it was found en masse deep in the Earth's oceans. Organisms in these regions receive no light from the sun at all, and they adapted to these conditions accordingly. The light they produce has specific purposes--finding prey, attracting prey, communication, and others I can't list off the top of my head. This is a product of natural selection--residual limbs, such as the human appendix, exist, but nature is very good at plucking off inefficient or unnecessary organs.

In Pandora's case, the bioluminescence really serves no purpose. Not only does everything glow, it doesn't seem to have a purpose for glowing. One of Cameron's arguments for its purpose is that Pandora has a very long night. He neglected something, though:

Pandora orbits very close to a planet the size of Saturn. It acts as a moon far larger and, as a result, far brighter than our own. It is tidally locked in the sky all night. Nothing needs bioluminescence; there's plenty of light, all of the time.

+ That is NOT Alpha Centauri
Alpha Centauri is the nearest star system to Earth. It's also a triple star system--the third companion is very dim, but the two primary stars would be easily resolved:

This image was taken by Cassini, orbiting around Saturn. The white band spanning the image is a segment of Saturn's rings. The two dots in the center are Alpha Centauri A and B.

A binary system allows for two orbital possibilities: an orbit around one of the stars--an orbit that would be unstable, insurmountably hot, and--as a result--not conducive to life, or around both the stars, but that begs the question:

WHERE IS THE OTHER STAR? If you're going to put your story in one of the most meticulously studied star systems in the entire sky, get your facts straight. Adding a second star would have been a simple change--they could do it in the 1970's, without computer effects.


Again, I don't mind fantastic voyages when they admit that they are completely made up. They make me itch, but I can deal with that. Don't, however, masquerade as some sort of scientific imagination sage. The movie fails to stand up to reality with respect to electrodynamics, gravitational mechanics, astronomical fact, and natural selection. As a result, it comes with little surprise that one of the science advisors for the film claimed to have received a PhD that he was never awarded.

Get your facts straight before you step into science, or science will step on you.

2 Comments:

Anonymous Anonymous said...

BUT.. BUT... IT'S SO PRETTY!!

Thursday, July 01, 2010 1:56:00 PM  
Blogger The Emperor of the Moon said...

I agree, and they ought to have left it that way instead of fabricating "causes."

Thursday, July 01, 2010 3:41:00 PM  

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