Physicists Robert Nemiroff and Teresa Wilson have written an article on their research searching for time travelers on the internet. This could turn out to be the scientific paper of the year! But, sadly, no evidence of time travelers was found. Slate summarizes the study here:
In a paper pre-published on arXiv, a pair of actual physics professors detail their exhaustive efforts to canvass the Internet for evidence of time travelers. Drs. Robert J. Nemiroff and Teresa Wilson of Michigan Technological University had me at the first line of the abstract: “Time travel has captured the public imagination for much of the past century, but little has been done to actually search for time travelers.” Say, that’s a good point!
They go on to explain that they approached the problem by scouring the Web for tweets, Google searches, and other online postings about events—such as a comet or the naming of a new pope—that hadn’t happened yet at the time they were posted. “Given practical verifiability concerns,” the researchers note, “only time travelers from the future were investigated.” That’s understandable: Time travelers from the past presumably wouldn’t have had prescient insights to offer.
Sadly, it seems, neither did any time travelers from the future. “No time travelers were discovered,” the researchers report, in what must rank as an early front-runner for most disappointing sentence of 2014. They conclude: “Although these negative results do not disprove time travel, given the great reach of the Internet, this search is perhaps the most comprehensive to date.”
Either time travelers don’t exist, or Star Fleet’s Department of Temporal Investigations is doing a bangup job of covering up their presence, so as not to contaminate the timeline.
Here is a link to the full paper.
On a (slightly) more serious note, the authors themselves distinguish between time travelers who want announce their presence and those who prefer to conceal it. The former type of time traveler, if they were present, could easily find ways to make themselves known. The latter type, if reasonably competent, could probably avoid detection by the sorts of relatively crude methods used by Nemiroff and Wilson. As with intelligent extraterrestrials, absence of evidence isn’t definitive evidence of absence, though it surely is relevant.
UPDATE: It is perhaps worth noting that many leading physicists believe time travel is possible, so research on the subject is not quite as silly as many people might assume. That doesn’t prove that it really is possible, or that anyone has actually done or it will do it in the future. I don’t have anywhere near enough expertise to have an informed opinion on either question.