Question

according to science are the aliens still existing?

Answer 1

Alien is a (extra terrestrial Creature) or foreigner from another planet, most of them believe that Aliens are real. So it might exist, but there are evidences found in some part of Mexico as well as Spain. 
i would say there is no answer for your question. even i also don t believe in Aliens.

Answer 2

many people think that aliens exist,some think they don't exist.It's all up in our minds that whether we want to prove that they exist or we want to prove that they don't exist.this is the same point that arises about mermaids and fairies,some people say they exist while some say they don't the ones who say yes searches and finds evidences about them but on the other hand the people who say they don't exist always try to find proof that they don't exist.I think this is all the game of mind if you want to prove that they exist i'm sure you'll surely grow up and become a astronaut and find a real alien and be the person who finds a alien or a whole planet where they live,but if you would like to believe that they don't exist you'll surely be sitting at your home and would be giving fake advises to people about their existence.