After carrying out the first search for evidence of time travelers using social media networks, a pair of physicists have turned up empty handed. This search for "prescient" messages online has yet to be picked up by a peer-reviewed journal, but the media has jumped on the news nonetheless.
GALLERY: Top 5 Sci-Fi Time Travel Methods
Although I filed this research under "There's too much cool sciencey stuff coming from the American Astronomical Society meeting in Washington, D.C. this week for me to find the time to write about time travel," I've received a few emails pointing me to this work. So, as it's Wednesday,* here we go.
Prescience in the Search Engine The crux of the study by astrophysicist Robert Nemiroff and physics graduate student Teresa Wilson from Michigan Technological University is that they carried out an unprecedented search of the Internet for any signs of prescient knowledge of future events. Of particular interest was any mention of "Comet ISON" or "Pope Francis". The idea is that should time travelers travel back in time from the future and arrive before Comet ISON was discovered (in September 2012) or before Pope Francis was elected head of the Catholic Church (in March 2013), they might have accidentally (or otherwise) let slip about these future events on an Internet-based platform. Both search terms were considered unique enough for there to be a very low chance of false positives.
Searching for prescient information on the Internet proved to be a somewhat tricky affair, however.
For example, using Google Search to tease out prescient mentions of "Pope Francis" or "Comet ISON" turned out to be "unreliable." As did Google's competitor Bing.com. The researchers then turned to social media for help. They carried out searches of all the popular social sites including Facebook, Twitter and Google+. Facebook, however, was another unreliable source of prescient messages as the platform allows back-dated messages to be published.
Twitter, it seems, reigned supreme. Yay Twitter.
"Our most comprehensive search for potentially prescient Internet content was achieved using the microblogging Internet platform Twitter," they wrote.
ANALYSIS: Time Travel? Don't Forget to Pack Your Wormhole
Assuming our temporal travelers were social media savvy, Nemiroff and Wilson found that hashtags ("#") were an especially useful tool for their hunt. They therefore tried to weed-out any mention of #cometison or #popefrancis before the events themselves occurred.
"No clearly prescient content involving ‘Comet ISON', ‘#cometison', ‘Pope Francis', or ‘#popefrancis' was found from any Twitter tweet - ever," they concluded.
Interestingly, they also rummaged through search queries (i.e. queries typed into search engines by Internet users) to see if anyone was looking for information about "Comet ISON" or "Pope Francis" before the events occurred. This search also turned up zero definitive prescient candidates.
Come to my Party, Yesterday Finally, they also tried to actively engage time travelers on Twitter. In September 2013, the hypothetical time travelers were asked, via an Internet forum bulletin, to tweet one of two hashtags on August 2013 - one month before the bulletin was sent out. Time travelers were requested to tweet either #ICanChangeThePast2″ or "#ICannotChangeThePast2″ - the first would be tweeted if the author's past could be altered and the second would be tweeted if the author's past could not be altered. A similar strategy was used by Stephen Hawking in 2009 who advertised a "Time Travelers Party" but only advertised the event after the party had taken place. Nobody - no candidate time travelers or random party crashers - turned up. Good effort though, Stephen.
This is the very basis of the "Grandfather Paradox" that posits that if reverse time travel were possible, could you go back in time and kill your grandfather. In this scenario, would you cease to exist in that timeline or would you cease to exist in another timeline? You remember when Marty McFly's hand starts to disappear during The Enchantment Under The Sea dance in "Back To The Future"? That paradox.
ANALYSIS: Could Higgs Particle be a Time-Traveling Assassin?
Using both passive and active means to find evidence of time travelers, no strategy turned up evidence of time traveler activity. "No time travelers were discovered," they wrote. "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, they are by no means proof."
Time Travelers: Not So Smart?
Although this Internet search was fun, and it demonstrates a potential strategy for teasing out prescient knowledge of events using social media, its limited scope greatly reduced any hope of success even if time travelers are out there. The study assumes that, a) travelers from the future want to be discovered or, b) they are careless to let slip about two specific future events. Both options I find difficult to swallow.
If the first option is true, and they used their future knowledge to be discovered, one would have to question their motives and/or sanity - aren't they breaking some time traveling "code of ethics"? If b) is true, the intellect of our future selves could be called into question. If they can't keep quiet and avoid babbling on social media, how the heck did they had the smarts to build a time machine in the first place?
ANALYSIS: Turning a Hot Tub into a Time Machine
Also, why would time travelers just pop onto the social web and start tweeting? No doubt they'd have the ability, but it's hard to see what they'd get from it - apart from giggling at Justin Bieber's "I've retired at 19″ tweets and lamenting that even in the year 2082, Biebs is still singing his little heart out and peeing into mop buckets.
And, why now? Sure, we think we're important and our era is unbelievably epic, but in the grand scheme of things, over tens (or hundreds) of thousands of years of civilization (from the past to the undefined future) - not to mention all those billions of years when humans weren't roaming around and polluting the planet - the early 21st century may not be all that.
Perhaps all the "cool" time travelers travel back to see the dinosaurs to experience the gritty Jurassic era; or explore ancient Rome to find out if Julius Caesar really was a tyrant or just misunderstood; or hit up the rowdy pubs of London during the Industrial Revolution? The problem with humans is that we all think we're special, that this time in history is special and we are the specialest of all special entities in all of human history.
What if our future selves think we're all a bit "meh" and crossed off the 21st century as a snooze fest? Assuming that these time travelers are even human! So many questions.
ANALYSIS: Brian Cox: Time Travel is Easy! Kinda
Scouring the Internet for prescient knowledge probably isn't very reliable anyway. If we were to scale this up, research hundreds or even thousands of search terms that could have only been thought up right at the time of a specific event and devoted a supercomputer (or a distributed computer effort SETI@home style) to trawl the web for "prescient candidates," the sheer number of false positives would likely cause the system to unravel. (Although, looking at the rapid advancement of computing, it's not that inconceivable that we might build some form of artificial intelligence that can pick through the web, searching for messages from John Connor. Wait a minute.) The Internet is not infallible, after all, regardless on how full-proof the researchers think data from Twitter is.
Limitations of this study aside, traveling back in time isn't thought to be physically possible anyway; only forward time travel is possible (and, actually, surprisingly easy) - unless you do some fancy stuff with wormholes. Time travel is therefore likely to remain firmly in the realms of science fiction. Also, there's that inconvenient idea that even if reverse time travel were possible, you'd only be able to travel back as far as when the time machine was first constructed. Bummer.
All that said, if you are reading this and you're from the future, please send me an email with 1) next week's lotto numbers, 2) the next 10 years of Superbowl winners and, 3) blueprints for the warp drive, that would sure come in handy around about now. Thanks.
*Just kidding, it's Tuesday.
Publication (pre-print): "Searching the Internet for evidence of time travelers", Robert Nemiroff & Teresa Wilson, 2013. arXiv:1312.7128 [physics.pop-ph]
UPDATE 1 (Jan. 10): I've just received my first email from a time traveling candidate! (Hi, 'Eli') Not sure if he's the real deal, but let's put it this way, I'll be betting on the next ten Superbowls.