Time travelers…..is there anybody out there?
Astrophysicists Robert Nemiroff and Teresa Wilson have undertaken what they consider to be the most sensitive and comprehensive search yet for time travelers from the future. The negative results they reported indicate that time travelers from the future may not amongst us.
Time travel has captured the public imagination for much of the past century. Modern fictional stories involving time travel to both the past and the future are not uncommon. Prominent examples are H G Well’s The Time Machine (1895), the Doctor Who television series (BBC, 1963 – present), Time Enough for Love (Robert Heinlein, 1974), The Flight of the Horse (Larry Niven, 1974) and the Back to the Future film trilogy (Steven Speilberg, 1985, 1989, 1990). These various stories present time travel as a technological problem to be solved – in the main ignoring, or skating over, the scientific and philosophic conundrums inherent in the concept of time travel.
Time travel at first seems reasonably plausible. Einstein’s theory of general relativity holds that we live in a 4-D world with time being just another dimension – like the other 3 familiar spatial ones. Then surely traveling in time is just technical matter – just like the other 3 dimensions?
Time travel to the future has a firm scientific footing – albeit an impractical one from the perspective of personally zipping to the future to check out how it will be. For example Special Relativity has clear sub-luminal solutions that correspond to time travel to the future. A famous example of this is Paul Langevin’s 1911 Twin Paradox. This was exploited fictionally by Robert Heinlein in his 1956 novel Time for the Stars, involving identical twins, one of whom makes a journey into space in a high-speed rocket aging far slower than the twin who remained on Earth. This twin paradox has been experimentally verified, for example, using precise measurements of atomic clocks flown on aircraft and satellites.
The science of time travel into the past however is far more controversial. The philosophy of time travel, when studied at anything greater than superficial level, is guaranteed to do your head in . This simple idea enthralls first-year undergraduate philosophy students as they grapple with time travel, freedom and deliberation. I will leave that comment for another time and instead will be challenging and suggest you read Ray Bradbury’s 1953 short story A Sound of Thunder, and answer, “How did they lay the path?”, then read Robert Heinlein’s 1959 short story By His Bootstraps, and answer “How did he start this causal loop?”, and finally be enthralled by Gregory Benford’s 1980 novel Timescape, which challenges the whole idea of determinism and time travel – brilliant reading.
Little, however, has been attempted to actually search for time travelers or evidence of them. I for one have always wondered why contemporary commentators of iconic historical events don’t include incredulous reports of unexpectedly large numbers of spectators or even participants. The Texas School Book Depository in Dallas, Texas, on November 22, 1963 would surely have been over run with time traveling tourists. As for the hill of Golgotha on April 7, 30AD – the crowds would be unimaginable.
However Michigan Technological University astrophysicist, Robert Nemiroff and physics graduate student, Teresa Wilson, have made a “fun-but-serious effort” to find travelers from the future by searching through internet records. They didn’t search for evidence of time travelers from the past; they couldn’t think of a test that would distinguish such a person, if they existed, from someone who has a knowledge of the past, which is most people. The authors also said that “to the best of our knowledge, human technology to create a time machine does not exist in the past, so that time travelers from the past must originate in the future, assuming such technology is ever developed.”
A time-traveler from the future might have left once-prescient content on the internet that persists today, or such information might have been placed there by a third party discussing something unusual they had heard. So they picked two events of unique significance that would remain well known into the future. The two events were the discovery of Comet ISON and the choosing of the papal name of the newly pope of the Catholic Church, Jorge Mario Bergoglio.
Comet ISON was discovered by the International Scientific Optical Network (ISON) on September 21, 2012. Therefore it came into public usage on this date. Furthermore histories of bright comets like ISON are generally well kept by astronomical societies and journals around the world, therefore it would be expected to remain memorable well into the future. Any discussions or even mentions of “Comet ISON” before September 21, 2012 could be prescient evidence of time travelers from the future.
Similarly on March 16, 2013 the term “Pope Francis” came into the public awareness when Bergoglio became the first pope to choose the name “Francis”. As papal histories are well-recorded by all manner of persons and organisations, for all manner of reasons, it again would seem reasonable that the term “Pope Francis” would remain ‘memorable’ well into the future. Again discussions or mentions before March 16, 2013 of Pope Francis might indicate the presence of time travelers from the future.
The researchers searched using Google, Google+, Facebook and Twitter to search for the terms “Comet ISON” #cometison, “Pope Francis” and #popefrancis. The terms were only found to exist post the dates that they entered the public awareness. The researchers also used Google Trends to ascertain whether any searches were made for these terms prior the events – this also proved negative. This allows the conclusion that if there were time travelers from the future they did not passively leave evidence on the internet.
What about an active response? here the researchers were not interested in conversing with time travelers, rather allowing them to indicate that time travel has become possible in the future. They did this by creating a post on a publicly available online bulletin board in September 2013, asking for one of two hashtag responses on or before August 2013. A message containing the term #ICannotChangethePast2 would indicate that time travel to the past is possible but that the time traveler believes that they do not have the ability to alter their past. Conversely a message containing the term #ICanChangethePast2 would indicate that the time traveler could change the past. Nemiroff and Wilson in their paper wisely steer away from the philosophical importance of these two stances and instead just look for the experimental results. At the time of writing no prescient tweets or emails were received.
The authors conclude:
Although the negative results they reported may indicate that time travelers are not amongst us and cannot communicate over the internet, they are not proof. It may be physically impossible for time travelers to leave any lasting remnants of their stay in the past, including even non-corporeal information remnants on the internet, or it may be physically impossible for us to find such information as that would violate some yet-unknown law of physics.
This could explain why there are no reports of huge crowds of time travelers at such historical events as the crucifixion of Christ or the assassination of President Robert Kennedy. Furthermore: “Time travelers may not want to be found, or may be good at covering their tracks.” Finally “our searches were not comprehensive, so that even if time travelers left the exact event tags […] we might have missed them due to human error.”
This is certainly a sensitive and comprehensive experiment and I think encouraging to others to develop and extend this to look for time travelers from the future.