I like science fiction movies. I love how it inspired scientists to speed up the breakthrough process. I love how it primed the leading research bodies to come up with a sensible products that are first deemed to be existing only in the aspect of fictional thought, things like teleportation, light saber, space travel, time travel etc. And while I'm weltering with fondness over it, I can't help but point some factual inaccuracies which is a given factor in a science fiction movies since writers are not physicists and scientists. But that is the whole point of fiction, I should say. Lately, I watched Battlefield(I am a sucker for Liam Neeson movies. He is good as he is tough). And here's are some enlightening truth as far as scientific perspective is concerned:
1) NASA discovered a "golidlocks" planet - True enough, there are already few of them found, but the golidlocks principle only assumes right proximity to the star system, which is neither too cold nor too hot to be able to possibly sustain life. The operative word here is "possible". It doesn't guarantee that it harbors life. If the planet is too large, it may have a densely gaseous region that it wouldn't be able to process building blocks of life in the ground. If it is small, it may have an extreme level of volcanic activity, lunar effects, and the entire landscape is maybe a shroud of radiation. Even if it has the same size as Earth, without the right moon to stabilize its axis, it would have suffered erratic seasonal condition.
2) NASA transmits beacon of signal into the goldilocks planet in 2005. By 2012, aliens responded and came into the Earth - We have a lot of exosolar planets found and the current database suggests a figure close to 600. But the closest goldilocks planet we have so far is the Gliese 581c which is 20light years away. If we send out a radio signal(electromagnetic wave) traveling a speed of light, it would take 20years to reach. But you can't do it in one perfect instance. It has to be sent repetitively in several succession because of the signal degradation. Remember that a vacuum is not absolutely vacuum, it has Hydrogen atom per cubic centimeter of space, and photons, a highly interactive particle of any light source, will have a high probability to hit these.
3) Aliens are sensitive to light - This is a question on evolutionary process. I mean how are they able to evolve into a highly complex biomechanical beings but unable to acquire gemmules, a hereditary particle secreted by cells necessary for environmental adaptations. Ok, a colleague of mine, a biologist, suggested that maybe they live in a dimmer place where the Sun is 30-40% darker than our own. Well, a star to that luminosity and temperature wouldn't be able to fuel energies necessary for life to consume. Vegetations wouldn't flourish, flora and fauna will have an extremely difficult time to withstand.
All in all, the movie is great and I would like to end my point by the statement being hurled in the movie, that during the alien invasion, especially those with highly developed technological advancement, it would be like the Columbus and the Indians, except this time, we are the Indians.