If you were a time traveler, what would you do to prove your powers were real?
Tweet about it, of course.
At least that's what astrophysicist Robert Nemiroff and physics graduate student Teresa Wilson at Michigan Technological University think you'd end up doing. That's why they tried to search for time travelers on Facebook and Twitter.
The pair searched the two social networks' backlogs for any mention of two events, the discovery of Comet ISON in September 2012 and the election of Pope Francis in March 2013, before they happened. Their theory, as presented in a paper published last month, was that if there were any postings containing "Comet ISON," "#cometison," "Pope Francis" or "#popefrancis" from before those dates, they may very well be from a time traveler.
Nemiroff and Wilson wrote that when they looked on Facebook for time-denying posts, they found "searches on Facebook turned up results that were clearly not comprehensive." Perhaps, like many present-bound humans, time travelers preferred to keep their Facebook statuses unsearchable.
But unfortunately for humanity and Hollywood, the researchers had no better luck on Twitter, where a majority of people keep their tweets public. But don't lose hope. As they explain in their paper, just because the two didn't see any time travelers doesn't mean they don't exist.
It might not be possible for time travelers to leave any evidence of their journey behind, Nemiroff and Wilson argue. Or "it may be physically impossible for us to find such information as that would violate some yet-unknown law of physics," they write. Or, "time travelers may not want to be found, and may be good at covering their tracks."