A popular thought among experts thinking about alien life is that any intelligent life we discover in space will be artificial. But how realistic is this notion?

A new paper about the bizarre interstellar visitor to our solar system says it may well be a lost alien spacecraft. But there's a big snag with that idea...

Some of this blog's readers would make really scary and really good alien invaders...

While we're trying to get aliens' attention with active SETI, we need to keep in mind that we talk to aliens at our own risk.

The more spread out an alien species is across the cosmos, the easier it would be to find and contact them. But how widespread could an alien civilization be?

Trying to figure out how smart alien life forms may be will involve jettisoning a lot of cliches about intelligence.

Dr. Jill Tarter of SETI weighs in on the Wow! Signal for Weird Things.

Could we have already been contacted by aliens and just don't know it yet?