I know what convergent evolution is :P. I'm just at a loss as to what is efficient about having large breasts, let alone why nature would pull it TWICE (and it's got nothing to do with breastfeeding, infants find it easier to nurse with smaller breasts than large) and have it scientifically believable.

Implying they can't make Avatars for the humans.

I consider Avatar to be a (mostly) "hard sci-fi" space opera with a number of fantastic elements (the "psyonic link" between the drivers and their avatars, the floating mountains, etc.) salted throughout the narrative.

It is grounded in scientific reality, for the most part, but James Cameron wasn't making a documentary nor was he trying to be "real" with the film (in my opinion) he was making.

He was making a science-fiction movie and like all movies, it is first and foremost a movie.

It is "real" up to a point, and at that point, it departs from reality and becomes fiction.

I applaud JC for most of the "hard-science" stuff in the film (the sublight transport to and from Earth and Pandora, e.g.) and I give him a pass on the rest because I recognize that he was making a movie, a made-up movie at that.

He himself has said in interviews and panel discussions that some of the stuff in the film is essentially fantasy. The explanation for the floating mountains, for example, would work fine in theory, but in reality, the magnetic fields needed to hold up the mountains would be so strong they would rip the hemoglobin molecules out of your body if you came anywhere near them.

Also, the combination of gasses in the Pandoran atmosphere would lead to a very, very bad acid rain and if you were outside in the open when it was raining, and you were wearing a t-shirt, you'd get seared by the rainwater.

Yet, we see people clearly walking around in t-shirts and we see floating mountains on Pandora.

As James Cameron has said, "the mountains friggin' float" among other things about his film. He knows it's a science-fiction movie and therefore it has to depart from reality. Avatar's departure from reality is farther down the spectrum than Star Trek, but Avatar does depart from reality.

It's a movie. Don't look at it too hard, sit back and enjoy it, and tell your inner science geek to be quiet and enjoy the movie.

That's what works for me.

Again, the floating mountains are 100% hard scifi.

http://upload.wikimedia.org/wikipedi...t_p1390048.jpg
That is an (inverted) floating mountain on a smaller scale, ON EARTH, TODAY. It is only inverted for ease of cooling the superconductor. The effect is exactly the same.

Yet again - haemoglobin is NOT ferromagnetic. It does not contain molecular iron - the iron is part of a compound. Iron compounds are NOT necessarily ferromagnetic. JC made a physics FAIL there (fair enough in an offhand remark in an interview), and it does not have to and should not be taken at all literally. If a magnetic field did strip haemoglobin from red blood cells then anyone who had ever received an MRI would be dead. The field of an MRI scanner can be up to 4 Teslas, which is enough to cause magnetic objects to fly across the room and punch holes through some materials and rip metal objects out of people's bodies, but a person can survive being exposed to the field with no problems. Pandora's magnetic field is stronger than Earth's (Earth's is 0.000003 - 0.000006 T ), but still weaker than such a field.
Acid rain is extremely dependent on environmental factors - acid rain on Earth is only around 4.0 at most (lowest). While the rain on Pandora would be acidic to a degree (as is natural rain on Earth), the scale does not mean that all acids are dangerous. Anyway, the two main gases that cause acid rain, SO2 and NOx, are both primarily produced by human activity. Pandora's atmosphere is high in CO2 and H2S compared to Earth, but these are not precursors to acidity in rainwater in the same way.
Personally, I would say Avatar is far harder than ST, which is one of the harder scifi works that is widely popular (yeah, not saying much).

Sexual selection.
Anyway, literally every other thing in it is done perfectly, a single departure is not only reasonable, but expected in order to make the Na'vi appealing.

Well, Cameron did note that he originally wanted Neytiri to have no breasts.

@up

Any source of that info ? I never heard of that,( from start he decided that Na'vi are mammals )

Oh I'm sorry; I meant they weren't designed to be mammals from the start. :facepalm: I was thinking the wrong thing.

I have a question that I've been meaning to ask the forum for a while, which is kinda related to this topic.

If you were one of the humans who stayed behind on Pandora, what would you miss about Earth? Even if you loved everything about Pandora and were happy, there would have to be *some* things you would get homesick for now and then. It could be big things, it could be little things, it could be things you don't even like that much but make you nostalgic. Any ideas?

I've already emailed you my list of ideas, but here's another one I thought of - city lights. There can be something really pretty about city lights, particularly when reflected on glass and water. I can see that being something the very urban humans missing.

i would miss:
-playing my guitar (if i didn't bring it with me)
-going to concerts
-watching new movies, listening to new music

It's not as if the humans don't have vehicles left. There are a few Samsons and possibly Scorpions that can be seen on the tarmac as most of the RDA personnel were herded onto the shuttle. Nevertheless, flying in a VTOL machine is nothing compared to flying on an ikran. (Although I had the strangest vision of a group of ikran and Scorpions flying in formation together O.o)

Anyways, time to comment on some of the more technical discussions. If I remember correctly, aircraft of Pandora are made of polymer, so magnetic field wouldn't affect their flight characteristics much. HNM, you have to realize that any conductor going through such a concentrated flux will not behave well for flight due to Lenz's Law. Try it yourself. Moving a piece of metal, any metal, through a sufficiently strong magnetic field would feel like moving it through syrup.

As for avionics, I think we can give JC the benefit of doubt and say that the electrical wiring and hardware are sufficiently shielded so that they won't blow when flying through those mountains. Perhaps some kind of active shielding is done to ensure the survival of the circuitry and other electronics.

As for Neytiri's breast, I've looked at them while she was running, and it seems that they don't wobble when she is performing aggressive maneuvers during the battle and when running. This leads me to believe that her breasts may constitute a significant portion of her pectoral muscles. As for why she even has breasts, I'm inclined to believe that it's a concession that JC made to science and probability to ensure that we can empathize with the Na'vi species.

People, this is science fiction, not a documentary. The point of this isn't to have the highest scientifically probably results. There are many more things I would like to discuss, but I'll put them into a later post, since I'm exhausted right now.

Really, just three things to any real extent. The people (if I had anyone on Earth I cared about) and the internet, as well as a few human-created things - primarily new music. Earth has some beautiful sights but I can see them and appreciate and remember them and not continually need them, plus in my opinion Pandora has better ones that I would be seeing every day :)