Time travel might seem like a work of science fiction, but some people are determined to prove that it is possible by turning to the internet.

This project was conducted by scientists from Michigan Technological University. The goal was to search for social media posts that mentioned events before they happened. 

The search was conducted in twitter, search engines, and the Astronomy Picture of the Day, and involved searching for terms based on the following criteria:

• They needed a search term that acquired a name between the period of January 2006 (because they were planning on using Twitter, and Twitter was established in 2006) and September 2013.
• They needed a search term with a unique label that wouldn't turn up lots of closely related results.
• They needed a search term that would remain important in the future that time travelers would still be likely to communicate about.

The researchers ended up picking two topics: "Comet ISON" and "Pope Francis". They then looked for any posts that existed about Comet ISON before it was discovered in September 2012, and any posts about Pope Francis before he was officially named the pope in March 2013.

In the end, their search turned up nothing. But while the experiment did not yield any time travelers, but the researchers outlined several possible reasons for this:

• It may be physically impossible for time travelers to leave any lasting remnants of their stay in the past.
• It may be physically impossible for us to find such information because it would violate some yet-unknown law of physics.
• Time travelers may simply not want to be found, and cover their tracks well.
• Time travelers might have not used those specific event tags.
• And of course, the researchers could have just missed them due to human error, non-comprehensive Internet searches, or inaccurate content time tags.

Either way, this is the most comprehensive search for time travelers ever conducted. You can check out the full results in the physics pre-publication database arXiv.