Do Alien Exist? I do remember once the famous physician, Stephen Hawking said that there are a possibility of alien invasion of the Earth. He said it would be a bizarre if they are happened to invade us and spreading diseases, because we will never have the immunity to resist the diseases. But, the question is, do Alien exist? In my opinion, no. I don't think that there will be other living things exist outside the Earth. Extraterrestrial being is something that would never be a logic, as far as the biological environment is concerned. I mean, is there any other planet is as good as Earth in terms of supplying the needs of living things? Scientists have already begun their search of extraterrestrial life years ago, but still in this very day, nothing found. They are not talking about the of possibility of a complex bionic creature like human would exist, they are talking about a simple microorganism like bacteria or algae but yet, false hope. Nothing exists out there, and believe me, they will never be. Do you think alien do exist? Give your say.