Meet the Profs
Princeton Faculty and what they're working on: Astrophysicist Richard Gott

Gott Time?
Watch out: Heading into the future may be coming sooner than you think

By Argelio Dumenigo

Time travel is often thought of as just a far off concept born out of the post-H.G. Wells science fiction canon.

But astrophysics professor J. Richard Gott *73 has joined the ranks of scientists such as Kip Thorne *65 and Stephen Hawking in giving what was once thought of as the impossible more validity with help from Albert Einstein’s theories of special and general relativity. Gott, who has been teaching at Princeton since 1976, also employs pizza, string, miniature footballs, and just about any other object he can use that might make understanding the heady concepts involved with traveling through time easier for his students and others.

When he first arrived to teach at Princeton in 1976, Gott developed one of the nation's first courses in general relativity for undergraduates and continues to teach it. In one of his other classes, The Universe, which is geared towards non-science majors, he and his coprofessors draw about 240 students a semester. He won Princeton’s President’s Award for Distinguished Teaching in 1998.

“It’s a fun topic people are interested in and it gives you a window on Einstein’s work, on special relativity and general relativity,” says Gott, who authored Time Travel in Einstein’s Universe last year and has been tapped by mainstream publications such as Time magazine to discuss in plain English what he and his colleagues have discovered about the possibilities of time travel.

“Rather than taking out patents on time machines,” he jokes, “we’re basically trying to explore the laws of physics in extreme situations, which may provide some clues as to how the universe works.”

Gott says Einstein told us how you could visit Earth 1,000 years from now. All one would have to do is get in a spaceship, travel to a star a little less than 500 light years away at about 99.995 percent the speed of light, and return at the same speed. Upon arrival, Earth would be 1,000 years older, while the traveler would have only aged 10 years.

According to Gott, humans have already traveled through time. The greatest time traveler of all? Russian cosmonaut Sergei Avdeyev, who was in orbit for a total of 748 days during three space flights on Mir traveling 17,000 mph. He eventually aged 1/50 of a second less than he would have if he had stayed at home. Thus, when he returned to Earth he found it to be 1/50th of a second to the future of where he expected it to be.

It does not seem like much, but Gott points out that the Wright Brothers only traveled 120 feet in their initial flight.

While travel far into the future would require a great deal of effort and investment, Gott believes it is more likely than traveling into the past, which would require manipulating large masses. Using the “cosmic strings” theory Gott developed in 1991, which involves filaments of very dense material left over from the early universe, he says it would take a time machine with half the mass of our galaxy to travel one year into the past. Just understanding whether such possibilities may be realized may require us to develop a theory of quantum gravity (how gravity works on microscopic scales) — one reason the problem is so interesting.

Where would Gott go if he had a time machine? “I would like to see Earth 200,000 years in the future to see if the human race had survived and, if so, what people were up to,” says Gott.

You can email Argelio at dumenigo@princeton.edu