In the early years of the last decade 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.
In August 2013, Nemiroff and Wilson searched for posts made between January 2006 and September 2013 that mentioned either or both of two terms: “Pope Francis” and “Comet ISON”. These were chosen because they’re very unique terms - Jorge Mario Bergoglio is the first pope to take the name Francis, and Comet ISON is the only comet to have that particular name - and are therefore unlikely to have been mentioned by chance before they were coined (in March 2013 and September 2012, respectively).
There were three ways to see if anyone had let slip those terms before they should have. The first was a simple search using Google, Bing, Google+, Facebook, and Twitter, and it actually turned up a result - a blog post where someone talked about a future “Pope Francis”. “Butbut upon close inspection and consideration,” the authors wrote, “that blog post was deemed overtly speculative and not prescient.”
Second was to dig into what people had been searching for on search engines like Google during that time period. “A time traveller might have been trying to collect historical information that did not survive into the future, or might have searched for a prescient term because they erroneously thought that a given event had already occurred, or searched to see whether a given event was yet to occur,” Nemiroff and Wilson write. Google Trends doesn’t show anything for either search term, and neither Bing nor Yahoo! offer that kind of detail.
The researchers even get access to Nasa’s Astronomy Picture of the Day website stats, and have a dig around to see if anyone ended up landing on the homepage thanks to searching for Comet ISON. Still nothing.
The third (and final) method was interactive, asking time travellers to go back in time and reveal themselves by tweeting or emailing one of two phrases - #ICanChangeThePast2 or #ICannotChangeThePast2 - on or before August 2013. The two phrases were chosen because neither hashtag had ever been used before this study, and the researchers hoped that any time traveller who obliged would clear up a fundamental question about how time travel works.
But, of course, they did a search for the hashtags before revealing the request in September 2013, and inevitably nobody seemed to have travelled back in time to tweet or email.
What can we conclude from this? “Although the negative results reported here may indicate that time travelers from the future are not among us and cannot communicate with us over the modern day Internet,” the researchers write, “they are by no means proof.” There are all kinds of reasons why there might not be evidence left behind by time travellers, from the physical impossibility of changing the past to them simply being very good at covering their tracks. It wasn’t a comprehensive search either - all we know is that time travellers don’t use Twitter or Google Plus if they come back.
“This search might be considered the most sensitive and comprehensive search yet for time travel from the future,” the researchers write. The truth may be out there, but requires further investigation.