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Avatar: the real-life science behind the fantasy

Floating mountains? Glowing plants? They're in 'Avatar,' and they're not beyond the realm of scientific possibility.

By Staff writer / December 28, 2009

The floating Hallelujah Mountains provide one of the more exotic settings for the blockbuster science-fiction film, 'Avatar.'

20th Century Fox/Newscom


The producer of “Avatar” is fond of saying that writer and director James Cameron does not write science fiction, he writes science fact.

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From the reclining, cup-holdered seat of a local multiplex, that seems a generous statement. Neither mountains floating in midair or fauna that lights up like the Las Vegas Strip at night would seem to have the slightest foundation in reality.

And yet they do.

To be sure, Mr. Cameron likes to bring his fair share of Hollywood to the cosmos, painting his scenes with the brush of fantasy. But beneath some of his most outlandish visions is often a kernel of scientific possibility.

The floating Hallelujah Mountains

The topic of how an entire mountain range can bob over the landscape like corks is never explicitly addressed in the film, yet the explanation is woven throughout the story.

It all has to do with superconductors.

When superconductors are in the presence of a magnetic field, they can float. “Avatar’s” alien world of Pandora, it turns out, is simply a massive superconductor.

At the very beginning of the story, we are told that humans have come to Pandora to mine unobtanium. Unobtanium is the ultimate superconductor. (The very name, “unobtanium,” is a nod to sci-fi afficionados, who coined the word to describe a material with mythical properties.)

In Cameron’s world, unobtanium can conduct electricity without resistance at room temperature; the best current superconductors work only when the temperature is below minus 200 degrees F.

The discovery of unobtanium, which exists only on Pandora, revolutionized technology on Earth, the story goes, and the future human economy is dependent upon it.

On Pandora, however, entire mountains loaded with unobtanium float in the world’s massive magnetic field.

In a glimpse of how thoroughly Cameron has thought through the science behind his creation, he and his team have written a 380 page “Pandorapedia” that explains (among other things) the tectonics behind how such mountains could form.

In effect, they crumble upward.

This happens because Pandora is not a planet but a moon of a gas giant the size of Saturn – the fictional planet Polyphemus. Moons of gas giants are constantly tugged and deformed by the stresses of gravity.

One of Jupiter’s moons, Io, is pulled so violently by the gravitational forces of both Jupiter and Jupiter’s other large moons, that it has ground tides – the ground literally rises and falls like a sea tide on Earth. On a second moon of Jupiter, Europa, these tidal forces have heated the interior of the moon to the point that part of its crust has melted, creating a sea of liquid water beneath a surface of ice, scientists say.

On Cameron’s Pandora, those tidal stresses have fractured the landscape, and, in the case of the Hallelujah Mountains, sent it up into the sky. A companion book to the movie explains the larger process: “This … energy drives continental drift at a much faster rate than on Earth, causing tectonic plates to fracture more extensively because of the increased stress.”

Glowing plants

Cameron’s fascination with the deep sea has already led to one of the most successful films of all time: “Titanic.” It appears to have shaped “Avatar,” too. The oceans’ depths have a curious answer to sunlight, which has never been seen there. It’s called bioluminescence – organisms’ ability to create their own light.