In James Cameron's new fantasy movie Avatar, a private corporation conducts an off-world strip mining operation on the exomoon Pandora. The script places this world around a massive gas giant located in the Alpha Centauri system, which is a real star system some 4.4 light-years away from Earth. But space analysts say that conducting such a large-scale strip mining operation on a distant world would not be cost-effective. Also, it will not be able to achieve such a large-scale undertaking, even with the direction our technology is taking today.

In addition to that, it may also be that shipping the material unobtainium to Earth could be more expensive than the material itself. In the movie, we're told that the very rare element, for which no clear application is mentioned, costs about $20 million per kilogram, and that this is the main driving force behind the corporation's trips to Pandora and back. Though that may seem to be worth it at first, you need to consider the amount of energy it takes to bring the material back home.

In the first sequences of the movie, we are told that a journey to the Alpha Centauri system takes about 5 years, measured in the spacecraft's time. But that means the ship is traveling at at least 85 percent the speed of light. On the other hand, accelerating a kilogram of unobtainium, or any other material for that matter, to this amazing speed, requires 10^17 joules of energy. Currently, one dollar buys about 36 million joules, which means that one kilogram of the stuff costs about $3 billion to bring back to Earth. When taking into account inflation rates, of say 2 percent per year, the price may go as high as $50 billion in 2154 dollars. That's a lot less than the $20 million the material costs per kilogram.

“In other words, the transport costs for unobtainium exceed the value of the merchandise by a factor of more than 2,500! So that settles that. You are not about to pay $60,000 to Amazon as the shipping charge for this month's best seller. Interstellar mining – and the affront to natives it might imply – should be tactfully removed from Hollywood's box of tropes,” SETI Institute senior scientist Seth Shosta writes on Space.