While responses on Slashdot are often toxic, I was astonished that the responses here were so uniformly hostile to the very concept of mental illness.
Here? It's the same everywhere. People who have never been affected by mental illness (directly or indirectly) don't "get it" since it's not a visible impairment (like having no arms or legs) or even one that's easy to understand (being blind or deaf). They just think "Hey, my brain's working within its normal operating parameters, and so must be everyone elses."
For that, you need to let nature run its course. Literally. And that doesn't need require interference by someone who "knows" who's fit and who's not.
I once made the mistake of stating in public how I felt about a severely disabled couple having children(who would be also be severely disabled themelves) and was labelled all sorts of terrible things that are so far from my true nature it isn't funny.
So? If they were really "not fit", then this would manifest itself in a generation or two anyway. Absofrickinlutely no need to decide for yourself and hurry things up.
and its annoying as fuck cause the second they can obtain it even at 21mil a kilo its NOT unobtanium anymore its gonna have a fucking name associated with it.
It's something the marketing department came up with.
Hey, wouldn't _you_ want to buy one kilogram of pure unobtainium for $21M? It's an offer you just can't refuse.
But instead it turned out to be a magical spiritual world,
What's magical and spiritual about a bunch of frickin' trees forming some sort of neural network?
Those trees failed at performing actual magic any time given half a chance. Heal the wounded? Nope. Raise the dead? Nope. Smite the invaders with lightning bolts, earthquakes and fire from the sky? Nope, just a bunch of aggressive animals.
If you want magic, watch Star Wars. You can't poke a probe into the Force. You can poke a probe into the trees and investigate them.
and a collective thought borg of trees and animals.. and those that.. died?
So it's magic to remember the dead, or leave some records for the time after your death? Duh, we must be living in a very magical world then.
Have you ever heard of that ground-breaking engineering concept called "negative feedback loop"?
Durr, yeah. I have a degree in engineering cybernetics. Good enough for you?
However, in a self-sustaining chain reaction, the feedback loop must only be negative for certain operating conditions, or you won't get a self-sustaining chain reaction in the first place. You'll need positive feedback for starting the reactor, for example, and as soon as you have positive feedback loops anywhere, you're basically playing with fire. If you break that nice negative feedback loop that keeps your reactor from behaving nicely in any way (that could be the aforementioned idiot, bugs in the controlling software, simple mechanical problems, small design flaws, or, as in most previous cases, a wild combination of seemingly harmless flaws and errors), you're going to get the next TMI (not the next Chernobyl, as long as you don't fill the reactor with highly flammable materials).
i think you need to reread the article and some of the posts again. Decent design of failsafes requires no switch flipping, and cannot be overridden by a switch
That was a figure of speech. Instead of flipping a switch, it could be a small design error, a bunch of flaws that each by itself would be harmless, or someone _trying_ really hard out of either sheer stupidity or even malice.
... would say that a movie in which technology allows the hero to travel a few light years _and_ get laid by a hot blue-skinned alien is "anti-technology"? These people need to have their heads examined.;)
They'd probably say that Star Trek is anti-technology too, huh?
Anytime there's a chain reaction, there's a chance for it becoming uncontrolled, however miniscule. You just need to find the right idiot to flip the wrong switches.
The only way to have no chance of an uncontrolled chain reaction is not having a chain reaction in the first place, e.g. like in a fusion reactor, or using the neutrons from a fusion reactor to split fission fuel. No chain reaction, so just stop the neutron source and you only have decay heat to deal with.
He was taken to tour Pandoras forests in his own (i.e. as a cripple) body too.
He was wearing an exopack then. Remember how Neytiri takes it off his (human) face in the final scene of the movie, just before his avatar body opens its eyes?
There is no evidence that the Pandoran atmosphere contained any oxygen.
Jake didn't turn deep blue/purple (cyanosis) after taking a few breaths of it. That means his blood was being oxygenated by breathing the Pandoran atmosphere. _No_ oxygen at all in his lungs would mean that his blood would actually become deoxygenated while passing through his lungs, quickly leading to visible cyanosis.
There are a few other, more subtle hints, like the exopacks not containing an oxygen tank (ok, they could contain soda lime and generate oxygen from carbon dioxide in the atmosphere).
Where did you get the idea that compounds must be corrosive/toxic?
There are some that aren't, but as far as I'm aware, the list of harmful compounds is much longer than the one of compounds that are harmless on skin contact.
The oxidising agent need not be in the air. Combustible material in a heated condition could release such an oxidising agent, which oxidises a strong reducing agent from the air. Somewhat reverse of what typically happens on earth: heat wood/gasoline/ => release hydrocarbon etc. gases => oxidised by oxygen in air.
True. However, if the Pandoran atmosphere contained a (strong) reducing agent, then any contact of it with human-breathable (i.e. oxygen-containing) atmosphere would produce truly spectacular (exothermic, explosive) results. And this contact happens a couple of time in the movie, with the results being not really all that notable.
Also, many (if not all) possible reducing agents would fall in the "toxic and/or corrosive shit" category that is absent from the atmosphere. Especially everything that's a strong reducing agent.
They could be compounds too.
The "no toxic or corrosive shit" observation rules out many compounds, or at least high concentrations of them. The "nothing that reacts explosively in contact with oxygen" observation also rules out quite a few compounds.
The atmosphere _may_ contain significant amounts of noble gases (other than helium, which may have lent the movie a really funny aspect). I forgot about that.
I believe so. It wasn't made very obvious (just like the fact that the "real" Na'Vi only have four digits per hand, while the avatars have five), but you could see it. I think Tsu'tey got punched once and had a little bit of blood on his face.
Anyway, fire does not prove any oxygen at all.
Correct. Hence, I only used the possibility of fire as one hint of what's in Pandoras atmosphere, and what's not.
It might even be flourine - occurs to me more easily because it is Oxygen's neighbour in the periodic table.
See my other observations about the absence of overly toxic or corrosive shit in the atmosphere. That rules out fluorine and chlorine (at least in quantities suitable to maintain a fire), or else Jake would have spent the last two minutes of the movie coughing the bloody remains of his lungs out, and everyone would have had to wear full body protection equipment outside (Quaritchs quick trip outside to shoot at the helicopter would have been out, too). Also, both chlorine and fluorine have a characteristic color, while the atmosphere on Pandora was pretty much colorless.
If I were to guess, then the atmospheric composition of Pandora is 50% N2, 30% O2 and 19% CO2, and 1% other stuff. I might be wrong about the ratio of nitrogen to oxygen, since I believe the higher CO2 content leads to higher oxygen requirements to support combustion.
Uh, I don't recall seeing any mention of any of this in the movie.
Well, the flight was obviously sub-lightspeed, or else they wouldn't have needed the whole cryosleep thing (I believe in the beginning Jake talks about the flight not feeling like years, but rather like a fifth of tequila and a good asskicking). Pandora is in orbit around a gas giant in the Alpha Centauri system, which means it's "only" four light-years or so away. So, 4 years to send a message back to earth, and then the package you ordered takes another six to eight years to arrive.
It also looks like they never check back with the management on Earth, which would indicate that they don't have FTL communications, either. The technology in the movie is wonderfully "low tech" in this regard.
Sure, if the corporation were under those kinds of constraints, they should have given a lot more careful thought to their tactics.
From the improvised bombs (made from mining explosives - that's not really military-grade hardware) at the end, it can be gleaned that these constraints do exist. They couldn't just phone home and order a bigger bomb.
I got the impression that their atmosphere is very different, because humans had to hide behind the transparent mask to breathe properly.
Okay, here are my observations:
1. The atmosphere isn't overly toxic or caustic, since humans "only" need a breathing mask and not full body protection equipment. Also, humans can take a few breaths of the stuff and be just fine if they're brought back to a breathable atmosphere, which rules out really toxic shit like carbon monoxide or hydrogen cyanide.
2. The Na'Vi have red blood, so their respiration is probably based on oxygen. Also, fire is possible on Pandora, which also indicates that the atmosphere contains significant amounts of oxygen.
3. Humans show obvious behavior of suffocation when exposed to the atmosphere, which indicates that they cannot get rid of CO2 through their lungs. Which means that the partial pressure of CO2 in the atmosphere is too high.
Even on earth, we have 70-75% inert gas (for our breathing purpose) and we breathe quite fine.
Carbon dioxide isn't an inert gas for the human body. It's a crucial element in blood acidity regulation, and your body needs to get rid of all the excess CO2 it produces, which it can only do if the partial pressure of CO2 in the air in your lungs is lower than the partial pressure of dissolved CO2 in your blood. If the air you breathe (at atmospheric pressure) contains more than 8% CO2, you're in trouble, regardless of how much oxygen there is. (Respiratory physiology 101).
In enclosed spaces, CO2 also tends to collect at the bottom (since it's heavier than N2 or O2) and displace the other gases there, which is also dangerous, but a different mechanic altogether.
Humans hear well in only a particular frequency range.
Evolution probably limited this range to what's useful for us. If the Na'Vi have a similar hunter/gatherer lifestyle, the probably went through a similar process.
elephants, dogs, bats, snakes all have vastly different audio frequency sensing ability despite living in the same atmosphere.
Because hearing higher or lower frequencies was useful to them (and in case of elephants and bats - that they were able to produce those ultra-low or ultra-high frequencies themselves). Even if the Na'Vi had a slightly different range of hearing (say, 40-40000 Hz instead of our 20-20000 Hz), it wouldn't have a big effect on the plot.
But having said all that, still the amount of similarity with an independently evolved species is too uncanny for me to digest.
Well, it's improbable, but not impossible by our current knowledge. If the humans had FTL space ships, now that's something I'd file under "impossible".
Then again, the whole symmetry thing evolved independently several times on Earth, as far as I know. And a "double" symmetry is probably the easiest to come up with while still gaining whatever evolutionary advantage symmetric shapes bring.
can hear/see similar audio/electromagnetic frequencies
That's pretty much inevitable if life on Pandora started in water (which it probably did) and their sun has a similar spectrum as ours (looks close enough in the movie). Hearing also depends on the atmosphere there, and it doesn't seem to be too different from Earths to make a difference (apart from the large helping of CO2).
I was simply stating that a couple of bows, arrows, and charging animals wouldn't stop a corporation that truly did have permission to do whatever they wanted on the planet.
Problem is, they lost most of their military assets on the planet because they made a bad decision, and everything has to be shipped in from five light-years away. Whatever they may have really needed, they didn't have it at that point and they had no way of ordering it (remember that it takes four years for the message to get to Earth, and then another six or seven for the ship with the stuff you ordered to arrive).
The movie was a contrived situation so that we could depict noble natives overthrowing an evil corporation bent on domination.
Well, I don't think the situation was all that contrived, given the obvious disadvantage the humans had (limited transport capabilities, I believe there are only nine of those interstellar ships available, and one heck of a latency (one decade ore more) when ordering stuff).
Had the humans even suspected that what they were going to do was equivalent to poking a beehive with a stick, they might have considered less profitable, more diplomatic solutions. The movie missed a good opportunity for the corporation to make a cold, money-based analysis and come to the conclusion that the possible losses don't outweigh the gain.
In a real-life situation there would be governments involved, and the corporation wouldn't be wholly evil,
Well, the corporation wasn't even wholly evil. See my comments about not gunning down the Na'Vi. And the government doesn't own any interstellar spacecraft.
and the natives wouldn't be noble, and regardless of what happened the natives would lose unless the invaders decided to go easy on them.
Supposedly there will be two more movies. I suspect that in one of them, however, Earth will go down the drain permanently and completely, so that packing up and going back isn't an option for the humans - nor calling for more reinforcements.
I mean, what evolutionary pressure could possibly drive an animal to having a built-in "make me your mind-slave" link?
Being slaughtered and eaten immediately if the link is not present or not working well.
Humans have this technology too, by the way. Just bit more primitive (doesn't use direct connection between nerve cells), and it's kind of hard-linked to the reproductive system.
Since the whole planet was toxic anyway, if they REALLY needed the ore that much they'd just nerve gas the entire area.
The crooks in the government are not handing out WMDs to their crooked corporate buddies. No way. That'd be like screaming "Get rid of me, and hit me with this stick I give you.".
Besides, the point was to get the Na'Vi to move away without killing every single one of them. Remember how Quaritch did _not_ give an order to gun down the Na'Vi on the ground, even when they undoubtedly attacked the Dragon? I'm sure the defensive systems of the Dragon would have eradicated the entire tribe even faster than a load of nerve gas, at the touch of a button.
They'd also not do their bombing runs at 25mph and 100 feet of altitude.
Since their "bombs" were improvised devices built with mining explosives, I doubt that they'd make a very effective weapon when dropped from 30000 feet moving at close to mach 1.
Are space shuttles nature's technology replicated in a crude form on a human scale?
Try taking away everything that appeared millions of years ago in nature (wings, locomotion by recoil, aerodynamic body, etc), and see how well the thing flies.
The science of Pandora is very well thought out. You want to know how the planet can keep cool? Well we don't know how much heat it receives from its suns. If it were less than Earth, then you might as well ask how it keeps warm?
Pandoras atmosphere is 18-something percent CO2. It wouldn't be surprising if the temperature difference between the poles and the equator would be much less pronounced than on Earth. See Venus, for example, where the temperature distribution is pretty much uniform.
It might also explain why things can fly on Pandora that would only fall on Earth - the atmosphere is denser, so there's more buoyancy. That, and the gravity is lower than on Earth (but not by much, apparently).
Slashdot Mirror
Here? It's the same everywhere. People who have never been affected by mental illness (directly or indirectly) don't "get it" since it's not a visible impairment (like having no arms or legs) or even one that's easy to understand (being blind or deaf). They just think "Hey, my brain's working within its normal operating parameters, and so must be everyone elses."
In nature it's called survival of the fittest.
For that, you need to let nature run its course. Literally. And that doesn't need require interference by someone who "knows" who's fit and who's not.
I once made the mistake of stating in public how I felt about a severely disabled couple having children(who would be also be severely disabled themelves) and was labelled all sorts of terrible things that are so far from my true nature it isn't funny.
So? If they were really "not fit", then this would manifest itself in a generation or two anyway. Absofrickinlutely no need to decide for yourself and hurry things up.
And this year, the choco ration is rising from 20 grams to 25 grams!
Don't forget that this years gram was increased to 75% of last years gram.
The viperwolves, thanator, banshee and great leonopteryx appear to have only two eyes.
It's something the marketing department came up with.
Hey, wouldn't _you_ want to buy one kilogram of pure unobtainium for $21M? It's an offer you just can't refuse.
What's magical and spiritual about a bunch of frickin' trees forming some sort of neural network?
Those trees failed at performing actual magic any time given half a chance. Heal the wounded? Nope. Raise the dead? Nope. Smite the invaders with lightning bolts, earthquakes and fire from the sky? Nope, just a bunch of aggressive animals.
If you want magic, watch Star Wars. You can't poke a probe into the Force. You can poke a probe into the trees and investigate them.
and a collective thought borg of trees and animals.. and those that .. died?
So it's magic to remember the dead, or leave some records for the time after your death? Duh, we must be living in a very magical world then.
Durr, yeah. I have a degree in engineering cybernetics. Good enough for you?
However, in a self-sustaining chain reaction, the feedback loop must only be negative for certain operating conditions, or you won't get a self-sustaining chain reaction in the first place. You'll need positive feedback for starting the reactor, for example, and as soon as you have positive feedback loops anywhere, you're basically playing with fire. If you break that nice negative feedback loop that keeps your reactor from behaving nicely in any way (that could be the aforementioned idiot, bugs in the controlling software, simple mechanical problems, small design flaws, or, as in most previous cases, a wild combination of seemingly harmless flaws and errors), you're going to get the next TMI (not the next Chernobyl, as long as you don't fill the reactor with highly flammable materials).
i think you need to reread the article and some of the posts again. Decent design of failsafes requires no switch flipping, and cannot be overridden by a switch That was a figure of speech. Instead of flipping a switch, it could be a small design error, a bunch of flaws that each by itself would be harmless, or someone _trying_ really hard out of either sheer stupidity or even malice.
They'd probably say that Star Trek is anti-technology too, huh?
The only way to have no chance of an uncontrolled chain reaction is not having a chain reaction in the first place, e.g. like in a fusion reactor, or using the neutrons from a fusion reactor to split fission fuel. No chain reaction, so just stop the neutron source and you only have decay heat to deal with.
Odd. They lost the HP way a long time ago.
He was wearing an exopack then. Remember how Neytiri takes it off his (human) face in the final scene of the movie, just before his avatar body opens its eyes?
Jake didn't turn deep blue/purple (cyanosis) after taking a few breaths of it. That means his blood was being oxygenated by breathing the Pandoran atmosphere. _No_ oxygen at all in his lungs would mean that his blood would actually become deoxygenated while passing through his lungs, quickly leading to visible cyanosis.
There are a few other, more subtle hints, like the exopacks not containing an oxygen tank (ok, they could contain soda lime and generate oxygen from carbon dioxide in the atmosphere).
Where did you get the idea that compounds must be corrosive/toxic?
There are some that aren't, but as far as I'm aware, the list of harmful compounds is much longer than the one of compounds that are harmless on skin contact.
True. However, if the Pandoran atmosphere contained a (strong) reducing agent, then any contact of it with human-breathable (i.e. oxygen-containing) atmosphere would produce truly spectacular (exothermic, explosive) results. And this contact happens a couple of time in the movie, with the results being not really all that notable.
Also, many (if not all) possible reducing agents would fall in the "toxic and/or corrosive shit" category that is absent from the atmosphere. Especially everything that's a strong reducing agent. They could be compounds too.
The "no toxic or corrosive shit" observation rules out many compounds, or at least high concentrations of them. The "nothing that reacts explosively in contact with oxygen" observation also rules out quite a few compounds.
The atmosphere _may_ contain significant amounts of noble gases (other than helium, which may have lent the movie a really funny aspect). I forgot about that.
I believe so. It wasn't made very obvious (just like the fact that the "real" Na'Vi only have four digits per hand, while the avatars have five), but you could see it. I think Tsu'tey got punched once and had a little bit of blood on his face.
Anyway, fire does not prove any oxygen at all.
Correct. Hence, I only used the possibility of fire as one hint of what's in Pandoras atmosphere, and what's not.
It might even be flourine - occurs to me more easily because it is Oxygen's neighbour in the periodic table.
See my other observations about the absence of overly toxic or corrosive shit in the atmosphere. That rules out fluorine and chlorine (at least in quantities suitable to maintain a fire), or else Jake would have spent the last two minutes of the movie coughing the bloody remains of his lungs out, and everyone would have had to wear full body protection equipment outside (Quaritchs quick trip outside to shoot at the helicopter would have been out, too). Also, both chlorine and fluorine have a characteristic color, while the atmosphere on Pandora was pretty much colorless.
If I were to guess, then the atmospheric composition of Pandora is 50% N2, 30% O2 and 19% CO2, and 1% other stuff. I might be wrong about the ratio of nitrogen to oxygen, since I believe the higher CO2 content leads to higher oxygen requirements to support combustion.
Well, the flight was obviously sub-lightspeed, or else they wouldn't have needed the whole cryosleep thing (I believe in the beginning Jake talks about the flight not feeling like years, but rather like a fifth of tequila and a good asskicking). Pandora is in orbit around a gas giant in the Alpha Centauri system, which means it's "only" four light-years or so away. So, 4 years to send a message back to earth, and then the package you ordered takes another six to eight years to arrive.
It also looks like they never check back with the management on Earth, which would indicate that they don't have FTL communications, either. The technology in the movie is wonderfully "low tech" in this regard.
Sure, if the corporation were under those kinds of constraints, they should have given a lot more careful thought to their tactics.
From the improvised bombs (made from mining explosives - that's not really military-grade hardware) at the end, it can be gleaned that these constraints do exist. They couldn't just phone home and order a bigger bomb.
Okay, here are my observations:
1. The atmosphere isn't overly toxic or caustic, since humans "only" need a breathing mask and not full body protection equipment. Also, humans can take a few breaths of the stuff and be just fine if they're brought back to a breathable atmosphere, which rules out really toxic shit like carbon monoxide or hydrogen cyanide.
2. The Na'Vi have red blood, so their respiration is probably based on oxygen. Also, fire is possible on Pandora, which also indicates that the atmosphere contains significant amounts of oxygen.
3. Humans show obvious behavior of suffocation when exposed to the atmosphere, which indicates that they cannot get rid of CO2 through their lungs. Which means that the partial pressure of CO2 in the atmosphere is too high.
Even on earth, we have 70-75% inert gas (for our breathing purpose) and we breathe quite fine.
Carbon dioxide isn't an inert gas for the human body. It's a crucial element in blood acidity regulation, and your body needs to get rid of all the excess CO2 it produces, which it can only do if the partial pressure of CO2 in the air in your lungs is lower than the partial pressure of dissolved CO2 in your blood. If the air you breathe (at atmospheric pressure) contains more than 8% CO2, you're in trouble, regardless of how much oxygen there is. (Respiratory physiology 101).
In enclosed spaces, CO2 also tends to collect at the bottom (since it's heavier than N2 or O2) and displace the other gases there, which is also dangerous, but a different mechanic altogether.
Humans hear well in only a particular frequency range.
Evolution probably limited this range to what's useful for us. If the Na'Vi have a similar hunter/gatherer lifestyle, the probably went through a similar process.
elephants, dogs, bats, snakes all have vastly different audio frequency sensing ability despite living in the same atmosphere.
Because hearing higher or lower frequencies was useful to them (and in case of elephants and bats - that they were able to produce those ultra-low or ultra-high frequencies themselves). Even if the Na'Vi had a slightly different range of hearing (say, 40-40000 Hz instead of our 20-20000 Hz), it wouldn't have a big effect on the plot.
But having said all that, still the amount of similarity with an independently evolved species is too uncanny for me to digest.
Well, it's improbable, but not impossible by our current knowledge. If the humans had FTL space ships, now that's something I'd file under "impossible". Then again, the whole symmetry thing evolved independently several times on Earth, as far as I know. And a "double" symmetry is probably the easiest to come up with while still gaining whatever evolutionary advantage symmetric shapes bring.
That's pretty much inevitable if life on Pandora started in water (which it probably did) and their sun has a similar spectrum as ours (looks close enough in the movie). Hearing also depends on the atmosphere there, and it doesn't seem to be too different from Earths to make a difference (apart from the large helping of CO2).
Problem is, they lost most of their military assets on the planet because they made a bad decision, and everything has to be shipped in from five light-years away. Whatever they may have really needed, they didn't have it at that point and they had no way of ordering it (remember that it takes four years for the message to get to Earth, and then another six or seven for the ship with the stuff you ordered to arrive).
The movie was a contrived situation so that we could depict noble natives overthrowing an evil corporation bent on domination.
Well, I don't think the situation was all that contrived, given the obvious disadvantage the humans had (limited transport capabilities, I believe there are only nine of those interstellar ships available, and one heck of a latency (one decade ore more) when ordering stuff).
Had the humans even suspected that what they were going to do was equivalent to poking a beehive with a stick, they might have considered less profitable, more diplomatic solutions. The movie missed a good opportunity for the corporation to make a cold, money-based analysis and come to the conclusion that the possible losses don't outweigh the gain.
In a real-life situation there would be governments involved, and the corporation wouldn't be wholly evil,
Well, the corporation wasn't even wholly evil. See my comments about not gunning down the Na'Vi. And the government doesn't own any interstellar spacecraft. and the natives wouldn't be noble, and regardless of what happened the natives would lose unless the invaders decided to go easy on them.
Supposedly there will be two more movies. I suspect that in one of them, however, Earth will go down the drain permanently and completely, so that packing up and going back isn't an option for the humans - nor calling for more reinforcements.
Being slaughtered and eaten immediately if the link is not present or not working well.
Humans have this technology too, by the way. Just bit more primitive (doesn't use direct connection between nerve cells), and it's kind of hard-linked to the reproductive system.
The crooks in the government are not handing out WMDs to their crooked corporate buddies. No way. That'd be like screaming "Get rid of me, and hit me with this stick I give you.".
Besides, the point was to get the Na'Vi to move away without killing every single one of them. Remember how Quaritch did _not_ give an order to gun down the Na'Vi on the ground, even when they undoubtedly attacked the Dragon? I'm sure the defensive systems of the Dragon would have eradicated the entire tribe even faster than a load of nerve gas, at the touch of a button.
They'd also not do their bombing runs at 25mph and 100 feet of altitude.
Since their "bombs" were improvised devices built with mining explosives, I doubt that they'd make a very effective weapon when dropped from 30000 feet moving at close to mach 1.
Try taking away everything that appeared millions of years ago in nature (wings, locomotion by recoil, aerodynamic body, etc), and see how well the thing flies.
Pandoras atmosphere is 18-something percent CO2. It wouldn't be surprising if the temperature difference between the poles and the equator would be much less pronounced than on Earth. See Venus, for example, where the temperature distribution is pretty much uniform.
It might also explain why things can fly on Pandora that would only fall on Earth - the atmosphere is denser, so there's more buoyancy. That, and the gravity is lower than on Earth (but not by much, apparently).
Since the humans ultimately failed to obtain that rich deposit of unobtanium, it wasn't an oxymoron, just some subtle (unintended?) irony.
The unhealthy ones end up as snacks for the local fauna. Oh, and the careless, too.