Do you have an idea of what aliens from outer space look like or are you basing your ideas on pop culture representations?

On Neil deGrasse Tyson's science show "Star Talk," guest SETI Astronomer Seth Shostak and comedian Michael Ian Black discussed alien sightings and the way aliens are portrayed in the media.

"Most people who are into the UFO phenomena -- by the way, that's not a small percentage, that's one-third of the public," Shostak said in a video clip from the show. "There are 10,000-20,000 sighting reported per year in the US, so that's a lot."

While Tyson seems unconvinced, Black thinks this search for aliens is a deeper need for humans to believe there's more life in the universe than just us.

There's also an interesting side note about the common perception of what aliens look like. Instead of the familiar "X-Files" and "Close Encounters of the Third Kind" images of an alien with the tiny gray body, big head and bulging dark eyes, Shostak thinks they could be more machine-like in appearance.

"Think what we're going to do in this century... invent thinking machines," Shostak said. "The aliens have probably already done that. So the real aliens probably look like machines."