Avatarology

James Cameron's Avatar has spawned a great discussion about the plausibility of the science in the movie. General consensus so far is that Cameron did a great job of incorporating known scientific ideas into the story and that even the "suspension of disbelief" stuff is so mind blowingly awesome it doesn't draw too much attention to its implausibility.

A great read from Discovery about the science in Avatar can be found here.

Obviously the coolest thing in the movie were the floating mountains, which apparently are plausible within the framework of the story. Remember that the region contains a magnetic field so strong is throws off all instrumentation and the mountains are made of Unobtanium, hence, suspended mountains.

While I was watching the movie, two things in particular struck me.

1) Atmosphere composition. When Jake Scully is fending off the swamp dogs in the beginning with a torch I immediately wondered whether there would realistically be enough oxygen available to sustain a flame. Obviously this was a stupid question, of course there was, it's essentially the same as asking why our atmosphere permits fire: there is fire, therefore there is enough oxygen in this atmosphere. But I do know that if there were less oxygen in our atmosphere, fire could not sustain itself, and if there were more, then we could essentially set the atmosphere on fire in an uncontrollable burn.
Atmospheric composition also plays a role in the movie that was not immediately apparent to me. In the scenes where the Na'vi/Avatars fall from the tree tops down to the ground, I originally attributed their survival to hitting those big soft leaves on the way down. This is not the complete story however. The simplest explanation is that the force of gravity is not as strong; however, Pandora's atmosphere also helps our heroes out. Evidenced by the shots where the atmosphere mixes with the gases in the human research outpost module to create a blurry effect, they have different densities. For reasons I will not go into, Pandora's atmosphere has the greater density, which would help slow something that was falling in it.

2) Freaky Na'vi sex. My big question involved their ponytails. Is this how they get it on? They all wear loincloths, so I assume that they are covering something up. If they do have parts that resemble human sex organs, what happens when two Na'vi lock ponytails?

Before I close, I just wanted to point out that Sigourney Weaver had a great character to play (a more flattering depiction of a scientist) and played it well. Still got it. Also, I liked the irony of how the final fight scene was reminiscent of the climactic battle in Aliens, except the robot was not badguy and the alien was the goodguy.

Now I just have to save up enough money to see it in 3-D.