This piece first appeared on newstatesman.com.

In the early years of the last millenium there was a trend of people posting on internet forums claiming to be time travellers from the future. The most famous of these was John Titor, a name used by someone through 2000 and 2001, claiming that they were visiting from the year 2036.

Titor’s predictions ranged from the geopolitical to the scientific. He would share scans of the schematics for his time machine—installed inside a 1967 Chevrolet Corvette, no less—and claimed that 2004 would see a worldwide nuclear war that would reduce the United States to civil war.

We can be pretty sure Titor wasn’t a time traveller. His claim that the many-worlds interpretation of quantum physics was correct (and that, therefore, if something doesn’t happen in one timeline, it has to have happened in at least one other) is a convenient get-out clause for his incorrect predictions, many of which reflect the major events and scandals of the time like mad cow disease. He completely misses 9/11 and the war on terror, too, which is a pretty big omission.

How, though, can we be sure that there wasn’t a real John Titor out there, leaving a trail of predictive crumbs on some small message board in a corner of the web?

Physicists Robert Nemiroff and Teresa Wilson from Michigan Technological University have a neat paper called, suitably enough, “Searching the Internet for evidence of time travelers”, and it proposes three methods for seeking out evidence of of time travellers on the web. Spoiler: they don’t find anything. But it’s still an interesting idea to consider.