And why wouldn’t they? The idea of extraterrestrial life isn’t far-fetched as we continue to find more planets, as Former President Bill Clinton stated in an appearance with Jimmy Kimmel.
“If we were visited someday, I wouldn’t be surprised, I just hope it’s not like Independence Day, the movie, that it’s a conflict. May be the only way to unite this increasingly divided world of ours. If they’re out there, think of how all the differences among people on earth would seem small if we felt threatened by a space invader…”
“We know now we live in an ever-expanding universe, we know that there are billions of stars and planets – literally – out there. And the universe is getting bigger. […] Just in the last two years more than 20 planets have been identified outside our solar system that seem to be far enough away from their suns and dense enough that they might be able to support some form of life. So it makes it increasingly less likely that we’re alone.”
That expansion does pose a challenge to interstellar travel among more distant stars for both future humans and hypothetical extraterrestrial travelers, making visitation from distant neighbors a doubtful proposition (though science fiction has plot devices around that), but it certainly does indeed appear less likely, from a numbers standpoint, that we are alone.
He discussed his own journey of discovery, which he embarked upon after becoming President: “First I had people go look at the records on Area 51, to make sure there was no alien down there…” and further, “had all the Roswell papers reviewed.”
For those interested, the United States National Archives does provide information concerning documents (actual and fabricated) associated with UFO research.