FAQ

During some of the shots outside their home, you can see quite a few solar panels lined up, indicating that most or all of their power is solar power.

Not necessarily; the creatures could be so biologically different from our planet's lifeforms that a pathogen would be unable to successfully multiply inside their bodies or interact with their cells. In fact, bacterias and viruses are generally quite specific in terms of hosts; for example, only a relatively limited number of diseases on Earth can spread from species to species, say from animal to man, and the creatures' physiology would logically be very different from a human's (or any random Earth animal's). Ironically, the aliens would be much more likely to contract a disease from pathogens evolved in their own native planet.

Newspapers clips and notes briefly seen in the movie reveal that there were actually multiple landings, including for example in Asia (Shangai is specifically mentioned in an article).

Lee cobbled devices together from multiple hearing aids and other components. They aren't "off the shelf" products.

The feedback from any hearing aid is super sensitive to anyone not deaf.

The creatures are from another planet that had very low amounts of sunlight, which is why they have become blind.

However, their planet was destroyed, and on several chunks of meteors, the aliens escaped and eventually crash landed on Earth. It can be assumed that they did not burn up in the atmosphere because of their extremely strong exoskeleton.

So, these creatures are merely animals, just trying to survive and prosper on Earth.

It does not matter how loud the sound is, what's important is the type of the sound itself. Most likely the creatures can hear all noises that come from the family's farm. It is possible that the creatures got accustomed to the ordinary innate sounds, thus attract immediately to a human voice or an unusual sound (sound of objects falling to the ground, for example).

Second, whispering would exclude Regan

There is not much information about the alien's fighting capability, including the solidity of its armor and the resistance of this armor against heavy bullets, explosives weapons, electric shock, and thermal radiation. This topic is left open to the public's hypothesis. In the first scene, inside the store there are posters of missing people, indicating that aliens didn't attack humans in public once they arrived, instead, they were secretly hunting people in forests and remote places. It was too late when the government realized what is happening, most of the regions were lost to the aliens, many of the important facilities such as military bases have fallen and numerous amount of the army's recruits were killed. Just adding something else here. In the beginning of the film I caught a quick glimpse, if a news paper headline that said, "Aliens impervious to missiles!" That would seem that they're bullet proof too. The husband however, does look for his wife, later with a shot gun. Maybe bullets sting them.

There are a good deal of methods that could be utilized to defend against the creatures; some of them will kill them also. The problem is there would not have been much length to the film so the director and writers can't allow them. The creatures main flaw is it is vulnerable when it opens its mouth; where the tissue is soft. Flamethrowers and shotguns are good to have in that situation. If we got so technically exact with every film made we would never have a creature feature horror flick! :)

Although there is no official answer to this in the special features of the Blu-Ray edition, the answer could be two-fold. One, it takes several seconds to lace up a pair of shoes, which could make the difference between life and death or just an emergency when every second counts (such as lighting the fireworks near the end). Loafers would be OK and velcro straps are faster, but alas, the latter will make quite a bit of noise if you undo the straps.

Second, since a lot of the movie occurs a little over a year after everyone had to go silent, perhaps the family has gotten accustomed to this new lifestyle and were used to not wearing shoes any more so they didn't bother.

Having a deaf character in the family explains why they already know sign language, or their family version of it.

From what little is shown, the area around the waterfall is forested and not well suited for permanent habitation

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