Aside from lower cost, the big advantage of locally produced ammunition would be
optimization for local conditions. Since game laws or Geneva
convention restrictions would not apply, rifle bullets could contain
neurotoxins, explosives, or any other feature needed to deal with
either the local blue guys or big beasts.
To an elephant hunter in the early 1900s an AK-47 assault rifle cartridge
(2,000 joules of muzzle energy) would seem dangerously inadequate compared
to the premier elephant rifle cartridge of the era, the .600 nitro express (10,300
joules of muzzle energy). Yet in modern times, the AK-47, most likely fired
in fully automatic mode, seems to be the firearm of choice for
elephant poachers. Poachers have used such weapons to kill entire
families of elephants at the same time. It's hard to believe that the miniguns,
automatic cannons, and assault rifles of even 2009 would be incapable of taking out a dinosaur-like beast the size
of an elephant.
Strangely, the Avatar militia doesn't seem all that better
equipped than conventional 2009 military. Where are the super-capable drone
aircraft and robots? Why are the infantrymen not wearing invisible
camouflage? Why don't they seem to have any mature versions of the
smart bullets or
extreme accuracy guided bullets currently under development? In the
future, accuracy and kill rates for individual bullets will likely be much
higher. Hence, it may not be necessary to spray the jungle with dozens of
bullets for each attacker killed. With nanobot technology and
magnetorheological fluid body armor along with fibers such as
m5 polymer that's
superior to the Kevlar currently used in body armor, it seems like infantry
would be essentially immune to arrows, even Navi ones.
On Pandora, we once again see military guys tromping around in Amplified
Mobility Platform suits (AMP) apparently borrowed from Matrix movies.
However, at least these suits have enclosed cockpits, offering some
protection to their operators. Against modern weapons, AMPs with their high
profile and lack of heavy armor plating would be easily detected and knocked out,
but on Pandora, they make tactical sense. They could be designed to be arrow
resistant and used to transport heavy
weapons into places where normal vehicles would bog down.
While such suits might be conceivable, it's unlikely that they could move
with the agility depicted in the movie just from a mass to strength ratio
(see the chapter on scaling factors in our book). Make a device 2 times
taller than a human out of the same material with the same proportions and
it will take 8 times as much energy for the device to jump as high as a
human can. Make the device 3 or more times wider with metal construction and
the energy requirements of jumping get unmanageably high--the same reason
sumo wrestlers don't play basketball. Such a device could greatly exceed
human capacity for
picking up heavy objects but would be ponderous in a fist
fight or wrestling match.
Still, the main plot device in the movie is not the now stereotypical AMPs, it's the Avatars. These are remotely controlled 10 ft tall
artificial blue guys
grown using a combination of human and Navi DNA. The human controlling the
Avatar resides in a special chamber located some distance away but has the
illusion of actually occupying the Avatar's body. Aside from the
complexities of mixing DNA and creating an Avatar, there's going to be a
major wireless communication challenge not to mention bandwidth problem. The Avatar is going to have to transmit super high
resolution video from two eyes, stereo audio, smell, taste, and balance data
not to mention the touch, pain, and hot/cold sensations from thousands of
sensors in the Avatar's skin. In return the Avatar is going to have to
receive perfectly coordinated control signals for hundreds of different
muscles along with audio output.
imagine what would happen if service were interrupted even
briefly during a fight or when an avatar was leaping from vine to vine
across a chasm. Imagine what it would be like to converse with an avatar
while having even slight transmission delays or breakups.
The senor data and control signals would need to be transmitted at a real
time rates with enough redundancy and error correction to insure almost 100%
In an environment largely free of other electromagnetic (EM) noise and
transmissions, the communications might be possible if facilitated by the equivalent
of a cell-phone-like network of hidden towers and orbiting satellites to
relay the signals and prevent them from being blocked by things like
mountains. If an Avatar went in a cave he would need to spread
along the way to form a bread crumb-like ad hock wireless network capable of
relaying the Avatar's required control and sensor information. In fact,
marking territory with smart dust would likely become a regular Avatar
ritual. But, what about communication in the floating mountains?
Although they were visually stunning the floating mountains were arguably
the most ridiculous features in the entire movie. They were gigantic chunks
of real-estate floating in the sky apparently suspended by some form
of magnetic field. We surmised this from the fact that electronic
instruments on all aircraft in the vicinity are driven crazy by the area's
"high flux level", presumably a high magnetic flux level. Magnetic fields
are also about the only available explanation. Other possibilities such as
buoyancy, wind, and electrostatic forces are even more easily ruled out.
Unfortunately, the magnetic field strength needed to levitate mountains
would have numerous disastrous side effects on the movie's story line, that
is if the movie stuck to real physics. First
such a field would rip magnetic materials out of aircraft if they flew into it, but
that's just the beginning. Even if the aircraft had no magnetic materials in
them, moving a conductive material of any type--magnetic or
otherwise--through the field would create a large voltage difference across
it. All electronic systems or controls, not just the navigation systems
would be seriously disrupted. It's doubtful that an aircraft could fly in
Since both the human brain and heart are conductive, both would have
voltage differences generated across them by the motion of riding in an
aircraft. Any variation in direction or magnitude of the magnetic field,
even subtle changes from vibrations or body movements would induce random
currents in the brain with an endless list of possible results including
memory loss, hallucinations, psychotic events, and seizures. Randomly
induced currents in the heart could result in fibrillation and death.
Strong carefully controlled magnetic fields are used for inducing
currents in the brain as a treatment for
By comparison, the currents induce by flying around in a magnetic field strong enough
to levitate mountains would be orders of magnitude larger and more random in
nature. However, the floating mountains aren't the only questionable
features on Pandora.
To its credit, the movie lets us know that gravity conditions are lower
on Pandora than on Earth. This helps make the 10 ft height of the blue guys
a little more feasible. Otherwise their ability to jump around would be
reduced. Their hearts and circulatory systems would also need to be much
more robust just to overcome the blood pressure differences between their
head and feet, a problem that might otherwise limit their life spans.
However, the effects of reduced gravity apparently don't apply to humans. We
don't see them gaining any increased mobility.
The blue guy's slender build helps reduce their inertia,
again a critical factor in the ability to make quick movements. Inertia
comes in two forms: linear inertia, directly proportional to mass and
rotational inertia, directly proportional to mass and the square of the
distance of the mass from the center of rotation. Creatures with high
inertia will have difficulty moving fast. Since inertia is independent of
gravity, reducing gravity does not help
reduce the effects of high inertia.
An arm twice as long as normal will have
8 times as much linear inertia but 32 times as much rotational inertia
assuming it has the same proportions and is made from the same materials.
Making the longer arm thinner would definitely help. Slender 10 ft high blue guys would be able to move faster than heavy-set
Of course the blue guys have oversized eyes with large pupils because the
moviemakers know that audiences respond favorably to large eyes with dilated
pupils. Such large eyes and pupil dilatations would work quite well in a
dimly lit nighttime environment where practically all the vegetation
phosphoresces but would be over-designed in bright daylight. Blue guys would
probably not want to look directly at the sun for risk of frying their
retina. On the other hand, maybe the daytime star light is not so intense on Pandora.
The prevalence of six-legged beasts on Pandora is hard to explain from a
natural selection standpoint. How would an extra set of legs impart a
survival advantage? How would multiple nostrils at the base of their necks
be helpful? It seems like rain water would run down their necks and collect
in the nostrils.
Why would the blue guys be bipedal, have only four limbs, and human type
nostrils if evolved from six-legged neck-nostrilled ancestors? Furthermore,
why would a diversity of Pandorian life-forms including the Navi have a
tentacle-like appendage designed for directly connecting to and sharing
information with the brains of other life-forms? How could all these
neurological connector organs be compatible, unless the diversity of
life-forms had the remarkably similar DNA structures required to produce
such organs and the brain structure needed to use them? Again, such
connectivity implies common ancestry that doesn't otherwise seem to be
reflected in the Navi.
We also find it puzzling that a race of sentient beings like the Navi,
who supposedly live in perfect harmony with nature would have warriors. In
fact, if they were so harmonious and interconnected, why would they even know
Nevertheless, after a particularly egregious incident, the
blue guys, whipped into a frenzy by ex-marine Jake Sully (Sam Worthington)
in an Avatar's body, have had it with the humans and prepare to drive them off Pandora. There's no
lengthy discussion or thought given to a workable strategy. It's just let's
round up all the tribes and make a single decisive frontal attack.
Considering his military training, Sully should know better.
Occasionally, a force with a vast numerically superiority has wiped out a
much smaller but better armed force. Certainly, it happened to Custer
at the Little Big Horn, but such rare defeats have usually required
foolhardy behavior from the losing side's commander.
On Pandora the human commander Colonel Miles Quaritch (Stephen Lang) is no such fool. Realizing that the Navi
have started massing for an attack, he decides to blow up their sacred tree
of life in a preemptive airborne strike before they can reach overwhelming
numbers. He correctly determines that blowing up the tree of life would
demoralize his enemy and send them packing, permanently ending
the human/Navi conflict. According to the Colonel, his plan is the only way
to avoid being overrun and wiped out.
Maybe so, but we would point out that a dug in force armed
with modern automatic weapons, rapid fire cannons, and air support against a
mass attack of warriors armed bows and arrows is not the same thing as
Custer's disastrous cavalry charge. Custer's men were primarily armed with
single shot rifles and were caught in the open
Colonel Quaritch knows about the tree of life thanks to Jake Sully who
in Avatar form
has previously gained the confidence of the Navi only to act as a quisling
who passes vital information to the humans. Sully eventually discovers that
running around the forest as a blue guy is actually pretty cool. He finds romance, has a change of heart, and with a group of
human co-conspirators steals his Avatar along with the equipment needed to
drive it so that he can return to the Navi.
Here's the problem: Sully would also need to have control of the
cell-phone-like network required for maintaining the Avatar's control signals.
Even if the corporation didn't fully control the network, what's to prevent them
from wire-tapping into it and reading Sully's thought's as well as seeing
everything he sees. Yes, the information could be encrypted, by why
would an evil corporation spend billions on a system with encryption that it
couldn't decrypt? Even if that were the case, why couldn't they jam the
transmissions or simply destroy the
network? In fact, why would they even need Sully to gain information. Even in 2009 the U. S. military is already
developing insect sized crawling and flying robots capable of spying on
prototypes are already about 5 mm on a side and cost around a dollar to make. A corporation capable of
creating an Avatar could easily use advanced versions of these technologies
to spy at will on a primitive culture like the Navi.
For some reason, while preparing to blow up the
tree of life, Colonel Quaritch also to decides mount a land assault. The Navi meet the ground force head-on with a cavalry charge, a well known form
of suicide since at least 1914. And guess what? They get creamed. Meanwhile
other blue guys mounted atop flying critters swoop down on the aircraft from
Aircraft designed for ground assaults could indeed be
vulnerable from above. These aircraft used high speed counter-rotating
propellers contained in large circular shaped pods. Shooting one of the Navi's spear-like arrows or dropping big rocks into the rotor blades should
have severely damaged them and
disabled the aircraft. In addition to performing such attacks from the flying
critters, in at least some places, the Navi could have hidden archers atop
the floating mountains and rained arrows down on the aircraft attempting to
pass between them.
Instead, the Navi riding the flying critters mostly
shot arrows at the pilots sitting behind transparent canopies. Fortunately,
for the blue guys, the canopies proved to be strangely
under-designed for arrow resistance. In addition, the flying critters were
able in several instances to grasp and fling some of the smaller-sized
aircraft into nearby objects. The problem was that there just weren't enough
warriors on flying critters available to handle all the aircraft.
To the movie's credit, when the blue guys learned an attack was
they didn't use the usual
lets-build-a-cleverly-designed-fortress-in-twenty-minutes strategy so often
used in similar movie situations. The movie realistically portrayed the
situation: the blue guys didn't have a lot of options and would have been
crushed were it not for the fact that at just the right moment, when all was
about to be lost, the tree of life sent hoards of critters
to the rescue.
After the battle, the blue guys have a big celebration and send the
surviving remnant of evil humans back to Earth, but why? Do they really
think these people will be grateful and not bad mouth Sully as a terrorist or the Navi
as soulless assassins? Do they not think the survivors returning to Earth
will whip up popular support for a return invasion? And if an invasion force
does return would it again fool around with aircraft or ground assaults
when it could remain in orbit and rain warheads or herbicides down on the
tree of life while infecting the Navi with designer viruses? We'll have to
wait for the inevitable sequel to see if the invasion is deadly effective or just
another version of Custer's last Stand. Meanwhile, save your 3D glasses.
Judging from early box office numbers on Avatar, you're going to be using them a lot in the future.