Why would aliens kill us?

STEPHEN Hawking has warned aliens could kill humans if we ever try to contact them as he spoke out about his fears that alien life could conquer Earth. read more

But your depiction that sci-fi says aliens want to kill us is a pretty broad statement. Clearly that's not the case Star Wars, Star Trek, and many, many books. Perhaps you are talking about alien creatures, like the movie Alien. These monsters are not trying to kill us because they are aliens. read more

4) They kill us with the extraterrestrial equivalent of smallpox blankets While we often think of alien invasion as a deliberate destruction of humanity, there is a chance that they could hurt us completely unintentionally by bringing unknown diseases to our planet for which our immune systems have no defense. read more