Barack Obama clarifies he's seen 'no evidence' of aliens

Are aliens real. >> Uh, they're real, but I haven't seen them. And and and uh they're not being kept in uh what is it.>> Area 51. >> Area 51. There there's no underground uh facility unless there's this enormous conspiracy and they they hid it from the president of the United States.>> That answer quickly generating 26 million views online and lots of follow-up questions. >> Is this something that we should be concerned about. Back in 2007, candidate Obama sounded far less certain about life beyond Earth.>> ...