Headscratchers / After Earth

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• How does the Ursa sensing their prey by fear make any sense? When you look at predators in the wild, they often try to catch their prey unaware. When a human is afraid of a nearby Ursa, they are probably going to try to either flee or fight. On the other hand, a bunch of blissfully unaware humans who do not know to be afraid are going to pass right by an Ursa's attention when they would in fact be more vulnerable then. Why not just have the Ursa sense humans regardless of emotional state?
  • I'm more surprised by the fact that a space faring species that can create monsters that see fear, doesn't add another sense of sight once the first one has proved to fail.
  • I'm even more surprised that the Ursa can smell subtle scent of pheromones secreted by fear, but can't smell the horrible stench of a boy who has been running, jumping and fighting for days without a shower.
  • Or a civilization which doesn't bother building a full-body fear-masking suit or a robot that would make fighting Ursa easier.
  • I'm more surprised at the fact that Ursas apparently ignore every other sense in favor of the fear smell. I mean, in Cypher's story of his first ghosting, he mentions removing an Ursa's pincer from his shoulder, but that it still doesn't see him; can't it sense a human touching its arm, or remember where he was before ghosting?
    • To be fair, Cypher never actually stated that the pincer in question was still attached to the Ursa. Bladed weapons are standard human equipment in this 'verse, after all.
  • On a related note, if the Ursa can so easily sense humans by smelling their fear-based pheromones, how come Kitai stopped smelling afraid when he calmed down after having been terrified? Does calming down magically make the already-secreted molecules in his bodily secretions instantly disappear? Also, how the heck could the thing track him underwater in the caves?
    • Or race up a mountainside full of molten lava pools without getting roasted, for that matter? Kitai himself had to jump or scramble past several of those on his way up the volcano, yet a creature that can't sense light or heat evidently sidestepped them all.
• Why don't humans just wear sealed suits instead of learning to mask their emotions? Would allow everybody to be a "ghost" winning the war with little effort.
• "Everything on this planet is evolved to kill humans." How does this make any sense at all? Why and how would animals adapt to kill something that hasn't been there for centuries?
  • Furthermore, for a planet where everything has evolved to kill humans, there aren't many creatures that try to outright kill Kitai. Sure, the river parasite, the giant bird, the panthers, and the monkeys try to kill him, but aside from the Ursa, those are all that go after him here. Not to mention that the monkeys only attack after Kitai angers them by throwing a rock at one.
    • The giant bird doesn't bother to incapacitate Kitai all that much to feed to her young, the panther is more interested in the baby birds than Kitai, and the monkey only really gets going after Kitai throws rocks at it. Honestly, "Everything evolved to kill humans" rings pretty hollow when the only creature that goes out of its way to attack Kitai on it's own is the river parasite and even after poisoning him it's non-fatal.
  • Actually, I thought it was supposed to be that "Everything on Earth has evolved to kill anything not of its ecosystem" and or, alternatively, unfamiliar, which case that would mean humans, seeing as they are no longer of its ecosystem, in which case unfamiliar. At the same time, the future humans have little knowledge of the creatures and ecosystems
    • So...the animals adapted to stimuli they have no experience with? Evolution does not work that way, that's why invasive species are so hazardous.
  • I think he was exaggerating to make his son more alert.
    • To scare him, so he won't let something like an Ursa sneak up on him, let's say.
    • Great, scare him to protect him from a monster that smell fear!
    • To be fair, he didn't discover that the Ursa had survived the crash or escaped containment until after he gave Kitai that warning and sent him on his way.
  • Radical idea: Maybe Cypher just doesn't know that Earth's organisms aren't inherently hostile to humans, due to having been indoctrinated with all the propaganda developed to discourage human soldiers from deserting the war against the Ursa and trying to re-colonize their old homeworld. Presumably it's easier to get people to stay on a planet where one species is trying to kill you if they believe everything will do so if you return to the only other life-bearing planet around.
    • But that planet's atmosphere is apparently toxic to humans... somehow, see the next point below. Regardless, if it's an unsolvable problem then why would they need any other deterrent? And if it was solvable then why wouldn't any of the humans want to resettle their home planet?
• What's the deal with the air? It can kill a human within minutes, because it's toxic or deoxygenated or whatever, and presumably one of the reasons for the exodus in the first place. So if it was bad enough for humans to abandon and quarantine the planet, how did the other animals manage to survive, adapt, and thrive? Evolution doesn't work that fast...
  • No, the air is clearly oxygenated, otherwise, the animals wouldn't be able to live on it but, maybe there is something in the air that only animals could tolerate.
    • That makes no sense. Animals don't have a universal poison resistance that humans lack.
    • Perhaps there was a toxic level of Carbon Dioxide (playing to the whole "save the planet" aesop) that the other animals and plants evolved to tolerate. How they could do this in such a short time is still confusing.
  • To be that human-specific, it'd have to be an omnipresent contaminant in the air that selectively targets biochemical processes unique to humans, like maybe a human-specific antigen in erythrocytes; the contaminant would adhere to them each time it's inhaled, and gradually shut down their oxygen-delivery. Non-human animals' erythrocytes, lacking the antigen, would be unaffected. So it's theoretically possible to achieve, just so wildly-unlikely that it would pretty well guarantee the contaminant was engineered, not random.
  • I got the idea that it was lower on oxygen, and the respirator fluids just helped him breathe more efficiently.
    • Then the surviving animals should've adapted to oxygen deficiency by becoming smaller and slower, not bigger and fiercer.
    • Maybe it is the exact opposite; the planet has too much oxygen, after all they do live in a planet with maybe less oxygen and/or ships with limited oxygen so they get sick from so much oxygen. Silly, but the movie has many problems anyway...
    • If anything, the more logical explanation would be that it's Nova Prime that has more oxygen and over the centuries humans adapted to that level, it's like comparing people who live at sea level to those who spend all their time in the high mountains, swap places and until they adapt the former will be easily winded while the later has seemingly boundless energy. Kitai probably would have acclimated given enough time that they didn't have.
• Why did Kitai's dad make such a big deal about the jump being reckless? Under normal circumstances, I could understand a father's protective care for his son, but they were both going to die anyway if his son didn't make it in time.
  • My personal theory is that he was riling up his son on purpose so he could be at his physical peak and do the jump; if you notice in that scene he looks at Kitai's vitals twice and notices his heart rate going up.
• Where on Earth (literally) are these folks? Did they crash land in an old national park? According to the backstory we took over MORE of earth after the time this movie came out - where are all the ruined cities, etc.? Not even a little piece of junk sitting around!
  • The is one part where the film is mostly right: a thousand years with zero human occupation could conceivably convert even a city like New York to an unrecognizable forest, according to the scientists who actually get paid to sit around and think about these things. If you dig, there might be some things still preserved underground (think petroleum storage tanks, underground safes in a vault, etc.), but the surface would be entirely "natured over".
    • Actually books and TV shows about a world without us kind of go back and forth on that.
  • Going by the cave paintings in one scene and overall area, I would say somewhere in Europe, seeing as those particular cave paintings resembled the ones in either France or Spain.
  • The movie was filmed in Costa Rica, a place where 25% of the land are protected areas, if that worth something.
  • The wildlife has definite hints of Africa about it.
• The spaceship has a fully operational computer and is obviously able to send out drones, regulate the air and temperature for Cypher, and keep tabs on his medical conditions... but no internal homing beacon that could be activated?
  • Worse, those drones can scour the landscape for signs of the Ursa, yet they can't just fly over to the tail section and retrieve the beacon?
• Humanity royally screwed over Earth, left their planet and landed on another planet... that was already inhabited. They tried to claim the planet and the "aliens" who already lived there created the Ursa. We sure the humans are the good guys in this story?
• After Kitai falls down from the poison, Cypher has a visual of his face on the screen while he lays there. How'd he get that angle? Isn't he supposed to be monitoring his surroundings via things on him?
  • The monitoring device Kitai was wearing likely just fell off as he collapsed.
• So the explanation for the humans' ludicrously terrible weapons is that they're trying to use the least advanced technology we can for Green reasons. Fine. Why is the mother using an advanced tactile holographic display to design her buildings? In the battle of extinction against alien monsters we decided to regress to melee weapons, but when it comes to architecture we're too good for a T-square?
  • For that matter, why are we limiting the growth of technology for a Green Aesop? Humanity started guzzling resources after the industrial revolution, certainly, but more advanced technologies can often allow fuel to be consumed more efficiently. How many modern firearms could have been made using the energy and materials that went into that Morph Weapon?
  • That and there are plenty of green projectiles that evidently no one uses. If they're already going to regress to using sharp sticks, why not use bows too? With their technology it'd be pretty easy to make a sort of preloaded multi-shot crossbow side arm with toxic arrow heads.
  • Not to mention that space travel would require HUGE amount of energy/fuel. Where do they get that? And if they can make that much green energy, what's stopping them from using it in weapons?
• What are a bunch of baboons doing hanging around in dense rainforest? Baboons are savannah- and highland-dwelling monkeys; they avoid deep jungle.
• If the Ursa sense fear, and only fear, why not combat them with machines? Present-day Earth has all sorts of unmanned machines of war, including drones and aircraft that mean humans don't have to be anywhere near the battlefield. A thousand years into the future, this technology should be far more advanced...and yet all we see of the war is sparsely-armored infantry being tossed into the jaws of the Ursa. We even see later in the film that this society has access to advanced drone technology.
  • The Green Aesop unfortunately allows the writers to be lazy - it's likely for the same reason why you don't see them using more advanced weaponry. In-Universe, it's probably because they figured that the drones being destroyed would make things moot. Although this does raise the question of why they don't just have drones flying up high and launching incredibly sharp sticks of wood from a distance that would gain momentum, making them just as lethal as bullets.
• Regarding the Ursa being transported in the ship that Kitai and his father were on: Why was it stored out in the open on the ship? Wouldn't it make more sense to have a wall blocking it off so that no one is tempted to get close to it?
• I guess animal life could use the same geothermal hotspots that Kitai uses in the movie, but how do plants from a tropical forest survive being frozen solid every night?

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