Computers

Paul Gilster: Taking time to contemplate the nature of time

CorrespondentJanuary 12, 2014 

What better time to speculate about the nature of time itself than early January? Most of us feel the year past has somehow flown, and it’s always a bit of an adjustment to add a different digit to the calendar. Just how mutable is time, and can we change the way we move through it?

Science fiction loves to play with time travel as a vehicle for paradoxes and social commentary. Physicists sometimes look at the idea and construct arcane ways of manipulating time that would require a universe worth of energy and demand technologies we can barely imagine. They’re just trying to figure out if there’s any way to do it that doesn’t violate known physics.

I like Stephen Hawking’s comment that if time travel were possible, we’d be seeing time travelers from the future popping up at all kinds of events. But who knows what people a million years from now might figure out how to do? Surely that thought was what propelled Robert Nemiroff to come up with a way to search for time travelers using the Internet. Nemiroff, a professor at Michigan Technological University, figured people in our time are obsessed with social media, so it made sense to scout these sites for evidence of future joyriders.

Looking for time travelers

What a wonderful jeu d’esprit! We haven’t a clue if going into the past will ever be possible, though we do know how to go into the future by moving fast, which is something Einstein explained a century ago. Move close enough to the speed of light, and you stay your normal self while people left behind on Earth age for hundreds or thousands of years. A classic “Twilight Zone” episode explored this, but so did many short stories in science fiction’s “golden age.”

Nemiroff knows about relativity, but he’s thinking about a far future sightseer coming back in time to take a look at the world of his ancestors. We don’t know how to do it, but why not look? Twitter and Facebook were the tools of choice. Working with students at the university, Nemiroff chose two news items from 2013 that were given wide coverage – the approach of Comet ISON to the sun, which didn’t turn out to be as spectacular as some had hoped, and Pope Francis, who in many ways did. But remember, we’re looking for time travelers. So Nemiroff’s crew scanned the social media sites looking for evidence that someone knew about them early.

Find Comet ISON mentioned before its 2012 discovery announcement, for example, and you’ve got a very peculiar post indeed, and a possible clue to someone out of sync with time. A final effort, published in September of 2013, asked readers to email or tweet in August of 2013 either “#ICanChangeThePast2” or “#ICannotChangeThePast2.” Nemiroff threw in Google and Bing as well as his social media sites. Nothing showed up that was even remotely suspicious.

Troubling paradoxes

This result could be described as an anti-climax except that Nemiroff didn’t expect to find time travelers in the first place. But no one has ever looked for time travelers on the Internet before, and Nemiroff knows that a genuine time traveler might run into paradox, making it impossible to leave any evidence even if he or she had somehow found a way to make it back to our time.

Paradoxes are trouble – you’d better not go back in time and shoot your ancestors, because if you did, how would you have been born in the first place? Some physicists play with this one, too, finding alternate realities springing from quantum mechanics that might at least give a good science fiction writer something to work with. As for Nemiroff, he presented a poster of his work at the American Astronomical Society last week, and his paper is now in wide circulation. Find a mention of that on Twitter a year ago, and you’re guaranteed to get his attention.

Paul A. Gilster is the author of several books on technology. Reach him at gilster@mindspring.com.

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