When it comes to the concept of time travel, there are many theories on whether it might be possible, and if it is, how it would work.

Many scientists have taken the time to think about this possibility, what it might mean for the world, how to accomplish it, and much more.

What isn’t nearly as popular, however, is having scientists actually perform tests to determine if time travelers have already visited our time period.

One notable example of this was when the well-known physicist, Stephen Hawking, sat in a room by himself on June 28th, 2009.

After that date, he sent out an invitation publicly to anyone who wants to join him.

The idea being that if time travelers from any point in the future see that invitation, they could travel back to 2009 and join Dr. Hawking in that room, thus proving that they are indeed traveling through time.

Disappointingly, nobody showed up to talk with Hawking.

Of course, there could be many reasons for this. Skeptics would say that they didn’t show up because time travel is impossible.

Others might suggest that nobody showed up because time travelers want to keep their existence a secret.

Still others would say it is because there is some universal law that we don’t yet know about that prevents time travelers from being revealed.

Whatever the case, it is always a good idea to run different tests to see if the results stay the same.

A group of physicists have decided to do that by searching the Internet for very specific things. Then, after they have completed their searches, they released details about what they would be looking for, allowing time travelers to see it, travel back in time, and leave traces online.

In the paper, they explain why this ongoing type of research is important:

“Even time travelers who want to advertise their presence may do so ineffectively. Those who want to hide their presence might make a revealing mistake, and those indifferent might or might not leave traceable Internet content.”

One of the tests they performed was to look for the presence of very commonly known information before it should have existed. In the paper released, they attempted to find anything online about Comet ISON (C/2012 S1).

In addition, they looked for information about Jorge Mario Bergoglio choosing the name Pope Frances upon his elevation to the head of the Catholic Church. If anyone wrote about either of these very specific, yet highly unusual, things prior to 2012, it would indicate that they were time travelers.

In the paper, they explain:

“Histories of bright comets like Comet ISON are generally well kept by societies and journals around the world, indicating that Comet ISON might remain memorable well into the future. Conversely, there is little reason for anyone without prescient information to be referring to something as ‘Comet ISON’ before 2012 September. Therefore, discussions or even mentions of ‘Comet ISON’ before 2012 September were searched for as potentially prescient evidence of time travelers from the future.”

They went on to ask time travelers to either email them at “home.nemiroff@yahoo.com” or post a hashtag of “#ICanChangeThePast2.”

Only after they looked for these thing did they tell anyone that they wanted time travelers to do these things.

Again, they found no indication that time travelers complied with their hopes.

The full paper, which has yet to be peer-reviewed, can be found on arXiv.

Just because this paper was unable to confirm time travelers doesn’t mean we never will.

If you thought that was interesting, you might like to read about a quantum computer simulation that has “reversed time” and physics may never be the same.