* Why did the "advance scout" declare humans purely destructive and in need of being killed off, then insist that they have a good side to them?
** The advance scout reached his conclusion very quickly, after calculating how long it would take before the [[GreenAesop Terran ecosystem was irreparably damaged]], but was slowly influenced by his own new human emotions, effectively deciding "anything that feels this good can't be all bad".
* Why does Gort open his visor only when he's attacking things in the arrival scene, shutting it down when he's standing still, and then proceed to spend half the movie using it to glare menacingly at people? For that matter, why does giant-robot-Gort exist at all if it's cloud-of-nanobugs Gort that's going to do all the work?
** Gort's visor serves the same purpose as his robot form: intimidation. He stays a giant robot most of the time because it's more impressive, then disassembles into the swarm when he doesn't need to be scary anymore.
** Why does Gort need to be intimidating I thought the point was to destroy humanity as quickly and painlessly as possible. Which to be fair a cloud of nanobugs probably isn't but that's a completely diffrent issue.
* Why can Klaatu barricade off a small area from the nanobugs, but not create a safe zone around himself to approach the sphere? For that matter, if the aliens want life to survive on Earth, shouldn't they have an OFF SWITCH for the nanobugs? And so on.
** Klaatu's barricade may have been merely taking advantage of the swarm's behavior: they're programmed to eat easily accessible things before attempting to fly through small spaces to reach less accessible things. That, combined with a signal such as "this area has already been cleaned" could have kept them away at least until they had finished eating everything else nearby. However, he couldn't use such a signal to designate an otherwise unobstructed area as off-limits. Likewise, the swarm was most likely programmed to stop once it had eaten enough to to remove the danger to the ecosystem, but leave enough for the planet to regenerate eventually. This may have consisted of eating all animals, all animals above a certain weight threshold, anything with a notocord, etc. Alternatively, it could be programmed to eat all the biomass, then use most of that to restart the biosphere (presumably in a way that would allow eventually colonization but wouldn't lead to the native development of sentience.
* If inhabitable planets are so rare, wouldn't thousands if not millions of aliens be studying us around the clock for at least several years, not one advance scout for 40 years to be interviewed by one later scout for 5 minutes, who then unilaterally decides to destroy everything?
** This is pretty much explained in the movie. Pretty much every space faring race (at least near enough to know of Earth's existence) is part of this collection of Civilisations that Klaatu refers to. And as stated by him, they've been observing humanity's progress for a very long time watching and waiting for us to 'clear up our act'. It was only those few (perhaps more than the one Chinese man) that chose to live among us who felt the depth and breadth of Human emotion. But from those only observing from the afar, it was our aggression and selfish nature that defined us, and could no longer wait, action had to be taken.
* What's a biologist doing figuring out advanced relativistic physics equations?
** OmnidisciplinaryScientist.
* Why does Jacob, a ''child'' who constantly goes on about how the aliens should be wiped out because they ''might'' be a threat, draw nary a notice by his mother or Klaatu for what he's saying?
** I was thinking about this as well, she could've told Jacob something along the lines of "There's no reason to fight someone if they don't want to hurt you" or something. But I figured she mostly stayed quiet because she didn't want Jacob to realize that Klaatu was the alien, which he eventually does anyway.
* These aliens, who clearly are using their own advanced technology, demand that Earth stop using its electricity. Hypocrites
** Even worse, when the scientist asks why can't the aliens just give us clean technology, Klaatu says that technology isn't the issue and it's because we refuse to change. Uh, we haven't changed because ''we don't have a clear alternative to change to''. It's not like the solution to all our problems is sitting in our laps and we're just being stubborn assholes; it's because we see the need to change but have yet to figure out how and manage the turbulence in doing so. Even Klaatu handing us the technology on a silver platter will severely screw our economy as oil and coal become obsolete. Do these aliens even understand the concepts of 'economy' and 'infrastructure'?
*** You kind of answered your own question at the end there. But I felt it was heavily inferred that if they do hand us say, a source of clean and infinite energy, what would we do with it? Privatize it? Weaponize it? As you said, giving us this technology will do more harm than good.
* Also, these aliens believe that we're destructive and warlike, and so decide to ''utterly wipe us out with flesh-eating nanomachines''. ''Damn'' hypocrites.
** Well, we're not meant to agree with them.
*** We're not? The impression I got was that we ''were'' meant to agree that we should probably die for our evil warlike polluting ways, but oh well, there's no superadvanced alien homicidal maniac ecoterrorists around to do it.
** The scientist even outright points this out in the very same "give us the technology" conversation, giving a NotSoDifferentRemark that Klaatu later ends up agreeing with. Klaatu's own people weren't any different from humans until things got so bad that they HAD to develop the technology to survive or go extinct. "Only at the precipice do we evolve" as the scientist put it. Klaatu's people have all the answers that would stop humanity from doing exactly what these aliens don't want them to do, but refuse because they're determined to use a genocidal solution regardless of the existence of other options.
* If you're trying to save the natural environment, why do you shut down all of humanity's advanced technology, forcing 3-4 billion humans to go out into the countryside and eat anything that moves and burn anything that burns in a desperate bid for survival?
** Not to mention that some things ''need'' power to keep running or otherwise very bad things will happen. Chemical processing plants? Nuclear reactors? Liquefied natural gas? Those ''need'' human maintenance and other sources of energy to keep running properly or they'll deteriorate. Hope the environment likes chlorine gas and nuclear radiation. ([[https://en.wikipedia.org/wiki/Aftermath:_Population_Zero See here]].)
* Why didn't the military once try nuclear attack on the swarm? Given the EMP ending, we could've had the same result with much less catastrophic effect on the planet.
** if the blast were low surface instead of high atmosphere, the EMP damage wouldn't have been that much.
** But what commander is going to order a nuclear attack on his own country?
** One who's aware that the alternative is to let the entire human species be eaten alive by killer nanobots?
* In the grand finale, Klaatu shows mercy on humanity but completely shuts down technology with an EMP blast that covers the entire planet (or at least a very large radius) presumably to prevent humanity's science from further harming the planet. How many deaths is everyone willing to wager emerged from downed airplanes, doctors currently performing operations and people with pace-makers at the time? And what's more, how much of a negative impact is everyone willing to bet effects humanity's future considering our major dependence on technology to keep our society going?
** Exactly. Yes, overuse of certain technology is bad (I think we can all agree it would be stupid to use high-tech nukes all willy-nilly). But, a '''huge''' percentage of technology today is necessary for human survival. Disabling all technology would cripple modern communication (Especially in cases where people need to pass on information to one another and as quickly as possible), medicine, and defense. Taking away all technology would set humanity back to the Stone Age and would cripple the species as a whole. There's a big difference between learning how to be responsible with technology and wiping out devices humans ''need'' to survive.
*** In the original film, the writers actually thought about this when deciding how Klaatu shutting down Earth’s power for half an hour would work, in that vulnerable people and critical institutions, such as people in planes, hospitals, and power stations, were exempt from the effects as it would result in people dying. Come 2008, it seems that this wasn't thought about very much by the new writers.
*** ''How does this plan of the ScaryDogmaticAliens even work?'' First of all, humanity has gone from being ignorant to extraterrestrial life, to '''outright hating them''' for crippling their civilization and sending everyone back to the Stone Age. What was Klaatu hoping to do? Does he not know or care that humans burned trees and hunted animals to survive before they burned coal?
* If inhabitable planets are so super rare that this alien federation of planets is going out of their way to observe Earth, judge humans, and then exterminate them to preserve it, why aren't they, you know, terraforming planets? With their nanobots and the ability to essentially lift off the various Earth species into space apparently on a whim they clearly possess the technology to do so. Let us wreck Earth if we want, in the few decades it'll take to do that these guys will have built 26 other inhabited planets.

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