Whether or not time travel is even physically possible remains to be seen. But researchers at Michigan Technological University have already started scouring the internet for evidence that we've been visited by tourists from the future. The theory is that anyone who has moved backwards through space-time may have left their mark by tweeting, updating Facebook or posting on Google+ (who knows, maybe it's super popular in the future). The team began looking for mentions of two particular terms, "comet ISON" and "Pope Francis" before they would have entered our lexicon on September 21, 2012 and March 16, 2013, respectively. The ability to backdate Facebook posts and the fact that Google Trends only picks up popular terms limited the effectiveness of those particular tools, but that did not deter the researchers.
They also performed a version of an experiment first conducted by Stephen Hawking in 2012, who sent out an invitation to a party after he'd already thrown it. Not surprisingly, no one traveled back in time to attend after they'd received the invitation. The Michigan Tech team decided to use Twitter hashtags instead. They asked people to tweet with #ICanChangeThePast2 and #ICannotChangeThePast2, then searched for messages including those tags that would have been sent before they put out the call to the would be time travelers. Unfortunately, none of their work turned up any evidence that there are currently people from the future in our midst. Of course, we already know they're here -- Nic Cage is the only evidence we need. The full academic paper awaits you at the source link.