“If aliens visit us, I think the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.”
The theory is that if Earth were to be visited by a particular race of aliens, it’d be because they would have used up all the resources on their own planet and they’d take what they needed from us. They would essentially be living as “nomads,” according to Hawking. The idea is presented in a clip from the show found here.
I’m not here to argue against what Hawking said. He’s a famous scientist, I’m just a guy with a keyboard. But let’s run through some possible scenarios.
Scenario #1: There’s No Such Thing As Aliens
Pretty boring, but that belief is out there. If the only intelligent life in the entire universe is found on Earth, which is basically located quite a stretch off the beaten path as far as our knowledge of the universe goes, then we can all just get back to our spreadsheets.
Scenario #2: Aliens Have Been Here Before
This is a more interesting scenario, in my opinion. Who’s to say that aliens haven’t been here yet? The Earth is 4.6 billion years old. If you subscribe to the idea that “Homo sapiens first arose in the Earth between 400 and 250 thousand years ago,” that still leaves a whole lot of time that hasn’t been accounted for yet.
Ancient Astronaut Theory posits that we’ve indeed been visited by aliens in the distant past and that these visitations accounted for such mysteries as megalithic structures like Stonehenge, Easter Island, and the Great Pyramids as well as “the sudden appearance of a technologically advanced human civilization,” according to author William Saylor.
So we’ve got the possibility that aliens came here long before we were around, took what they needed, and left, or the possibility that they came here while we were already around, gave us a bunch of advanced technology and built a lot of cool stuff, then left. Or maybe they stayed…