Stephen Hawking famously said, “If time travel is possible, where are the tourists from the future?” It was his way of saying that time travel can’t really exist. At least, not in the way we conceive it, which is  fluid movement from the past to the future and vice versa. In fact, time travel to the future is fairly firm in its scientific standing. The other way, well… Where are all the time travelers?

While Hawking’s quote has a lot of understandable merit, there is one problem. Have we actually tested it?

Robert J Nemiroff and Teresa Wilson from the Department of Physics at Michigan Technological University have. They searched the internet far and wide for time travelers focusing on prescient tweets, and search engine searches. Basically, they “search[ed] for content that should not have been known at the time it was posted.”

Their logic? Well, “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.” So, Time Travelers may be on the internet accidentally predicting our future because they can’t remember what year something actually happened.

The period they searched was from 2006 to 2013, and the topics focused on were Comet ISON and Pope Francis, as they are both unique events with unique names that are not likely to be repeated without there being an actual intent.

Despite sampling Twitter, Facebook, and search engine results, the search for time travelers on the internet was not fruitful. The last attempt was to ask people to retroactively tag a post as #ICanChangeThePast2. Unfortunately, no one was able to do so.

It’s important to note that the absence of evidence is not in fact evidence of absence, and the two researchers reason that the lack of informational artifacts from time travelers could stem from:

    1. It may be physically impossible for time travelers to leave lasting physical evidence in the past;
    2. Finding such information may violate the some yet unknown law of physics;
    3. Time Travelers may not wish to be found and know how to cover their tracks;
    4. Time Travelers may not have left the event tags they were searching for;

and evidence may not have been found due to human error.The paper ends stating that the search for time travelers on the internet may be our best and most comprehensive way to find them yet (that is, if they exist), and that the internet is still our best way to make a comprehensive and time sensitive search for time travelers. So we may see more of this research in the future. Should be fun!

For those of you who are interested in reading more, you can find the paper here.