Scientists have revealed that they are searching the internet for evidence of time travellers.
The bad news? They haven't found any - yet.
Physicists Robert Nemiroff and Teresa Wilson from Michigan Tech university said in a paper released last month that their experiments were designed to root out anyone visiting our world from another age.
The aim was specifically to find "a prescient mention of information not previously available" - in other words, an accurate prediction which was verifiably not just a good guess.
Three methods were used to look for evidence of time travel, all involving looking for predictions or mentions of the arrival of Comet Ison and the election of Pope Francis before both events occurred.
The first method scoured traditional social media sites, including Twitter. The second method used data listing searches made on Google and other engines, to see whether particular terms trended before they had any reason to spike (the researchers actually used data from an astronomy website in this case). The third method looked at emails and other peer-to-peer data, which could pre-date the event in question.
"Were a time traveler from the future to access the Internet of the past few years, they might have left once-prescient content that persists today," they said.
"Alternatively, such information might have been placed on the Internet by a third party discussing something unusual they have heard."
The researchers did admit one other downside to their experiment (other than the fact that Stephen Hawking had got there first with his party for time-travellers, held before he sent out the invites) - they only allowed for time-travellers going backwards. And unfortunately this is the one direction of time-travel that we have no evidence for - time-travel forwards is a scientific fact, and already has a human world-champion.
Regardless, they pressed on, carried out the test and found no evidence that anyone from the future is currently active online. Still, they add that only a small percentage of all internet traffic was searched, and said it was still worthwhile carrying out the test on a bigger scale.
"No time travelers were discovered. Although these negative results do not disprove time travel, given the great reach of the Internet, this search is perhaps the most comprehensive to date."
However there may be another reason no evidence was found - it may be impossible to find anything that might contradict the laws of physics, even if it exists:
"It may be physically impossible for us to find such information as that would violate some yet-unknown law of physics," the researchers said.
Which means that even if time-travellers are here, we can't find them, because they shouldn't be here.