I am a huge nerd
So as those following me on Twitter already know, I went to see Avatar yesterday. Overall I was very impressed, and while I can see the similarities, I think the “Avatar = Pocahantas” meme is reaching a bit. You could similarly argue that The Lion King = Hamlet; despite their common theme, both films have unique plots, characters, and details. I also get the criticism of it as an environmentalist film, because it is yet another “seriously, live responsibly and respect native peoples” film but really, you could do much worse with the preachiness (think Fern Gully). Considering that you can make an attack on pretty much any film’s message for being political or offensive or whatnot (like Wall-E’s “jesus people, stop throwing away so much shit and acting like fat-ass slobs” message), I think protesting Avatar on those grounds is kind of silly. After all, science fiction is largely allegorical in nature, and in growing up as a genre it’s also tackling much more complex themes like war, terrorism, leadership, and environmental stewardship.
Anyway, on to the main point of this ramble.
I’ve spent the better part of an hour today trying to work out why exactly Pandora’s atmosphere is so deadly to humans. I first wondered what the composition of the atmosphere was like, and whether it could differ substantially from Earth’s considering that it seems to have a similar ambient temperature, pressure, green plant-life (and thus chlorophyll, photosynthesis, and oxygen), and isn’t immediately fatal except when inhaled (since walking around in a t-shirt is fine). It also looks similar to Earth’s (in that it’s blue during the day and shows no additional signs of coloration), and chemical reactions like fire are similar to those on Earth as well in terms of color and behavior.
Based on this information, I rejected the notion that the air had to be composed of substantially different compounds and instead went looking for something that could occur naturally in relatively small quantities, not change the appearance or behavior of the atmosphere, and cause serious respiratory problems in human beings without being damaging to the rest of the body.
My first thought, after Googling for “deadly gases” (I am so going on a terrorist watch list one of these days) was that it could be phosgene, since the Wikipedia description only referenced respiratory symptoms, Other websites such as the CDC, though, indicate that it can also cause burns and legions on the skin, in addition to blurry vision. Phosgene could be produced in significant quantities on Pandora by combining a chloride byproduct of some biological process with the naturally abundant oxygen and bombarding it with UV light, which would be plentiful in such close proximity to a gas giant planet’s radiation belts (and the gas giant itself seems to be nearer to Earth’s orbit than Jupiter or Saturn’s, increasing the amount of solar UV radiation as well). Despite the plausibility of this process, the additional physical side effects of phosgene make it seem like an unlikely candidate, as human characters are often seen walking around without protective clothing on, just breathing masks.
Other possibilities include relatively more common gases such as sulfur dioxide, which can cause respiratory problems in humans at concentrations as low as 8 ppm. Given the likelihood of tidal stresses on Pandora due to its parent planet’s gravitational influence, it’s possible that a chain of active volcanoes exist somewhere on the moon which outgas significant quantities of SO2. I’m not sure how likely this is as a scenario, given that SO2 is water-soluble and produces acid rain, and the choking smell of sulfur isn’t mentioned at any time in the film by either the humans, the human Na’vi avatars, or the Na’vi themselves, but it’s another possibility.
Also, in addition to the atmosphere question, one of the friends I saw the film with brought up another interesting biology point. Terrestrial creatures such as mammals and lizards generally as a rule have 5 appendages (2 arms, 2 legs, and a tail, or 4 legs and a tail) and a head. While humans don’t have tails due to evolutionary changes, we do still at least have a vestigial tailbone. On Pandora, lizards and mammals seem to have, as a rule, 7 appendages (4 arms, 2 legs, and a tail, or 6 legs and a tail), yet the Na’vi have the more familiar (to us) count of 5. I’m not sure why evolution would have given rise to the kind of 6-legged creatures we saw in the movie to begin with (I’m willing to just go with that), but it seems odd that the Na’vi would have evolved away from such a common and seemingly important appendage as an extra set of arms the way humans have grown out of their tails. I’m not saying it’s impossible, it just seems unlikely, especially since even the relatively closely-related lemur things have 4 arms and 2 legs.
I could be shooting blindly here, since trying to predict natural evolution is always going to be a shot in the dark, but it’s something that struck me as somewhat odd and perplexing, like someone at Weta decided the alien fauna needed to look more alien-ish, and stuck an extra set of limbs on without focusing on the implications it would have for the Na’vi, evolutionarily speaking. However, given how well the entire biosphere seems to work together in the film (implying a considerable amount of thought went into it), I somehow doubt that such a simplistic decision could have passed muster during the design process. It could also just be a case of there being a directorial commandment that the Na’vi only have 5 limbs instead of 7 to make them more relatable, in which case I give a big wet raspberry to James Cameron for that decision.
So yeah, I’m a HUGE nerd. Anyone have any other insights for me to mull over on these or other topics?