Searching the Internet for evidence of time travel is a fun activity.
It all started over a poker game. Astrophysicist Robert Nemiroff and his students wondered if there were time travellers among us, would they be on social media? How would you find them? Could you Google them?
"The result was a serious-but-fun effort to tease out travellers from the future by sifting through the Internet. Unfortunately, we did not uncover any time machines but the search was nonetheless interesting," said Nemiroff, a professor at Michigan Technological University.
Nemiroff's team developed a search strategy based on what they call 'prescient knowledge' - If they could find a mention of something or someone on the Internet before people should have known about it, that could indicate that whoever wrote it had travelled from the future.
For this, the team selected search terms relating to two recent phenomena - Pope Francis and Comet ISON (a sun-grazing comet discovered in September 2012) - and began looking for references to them before they were known to exist.
The researchers used search engines like Google and Bing, and combed through facebook and twitter.
In the case of Comet ISON, there were no mentions before it was discovered by two amateur astronomers in Russia.
They discovered only one blog post referencing a Pope Francis before Jorge Mario Bergoglio was elected head of the Catholic Church March 16, but it seemed more accidental that prescient, claimed the study shared recently at the American Astronomical Society meeting in Washington.
In a last-ditch effort, the researchers created a post asking readers to email or tweet one of two messages - '#ICanChangeThePast2' or '#ICannotChangeThePast2'.
The invitation went unanswered too.
"I'm still not aware of anyone undertaking a search like this. The Internet is essentially a vast database and I thought that if time travellers were here, their existence would have already come out in some other way, maybe by posting winning lottery numbers before they were selected," chuckled Nemiroff.