Astrophysicists disagree on this.

Stephen Hawking stated "I am more convinced than ever that we are not alone." Then warned us to stop looking for them before it's too late.

Neil Degrasse Tyson has gone on record to say that he doesn't believe there is intelligent life form (arms, legs etc) beyond our planet (although he has vacillated on this), and now says we are at least 50 years away from making contact with them.

Physicist Brian Cox thinks we won’t hear from intelligent aliens anytime soon (if ever) because life forms at that level tend to out-engineer themselves into extinction; destroying themselves by creating more technologies than they have the social and political expertise to manage (does that sound familiar?)

What are your thoughts? Do you think aliens exist? That they walk among us (insert joke here). Do you care?