Dear Wonderfest friend,
Einstein has shown us that time travel is possible. In fact, special relativity theory* reveals that time travel is not just possible, it’s unavoidable! The relativity of time guarantees that my every motion “through space” causes a complementary slowing in my motion “through time” (relative to everyone who doesn’t move with me).
Physicists put it this way: “The moving clock runs slowly.” Always.
Fortunately, everyday motions cause a negligible amount of clock slowing. So, as I cruise down the highway, the clock in my car stays synchronized (synchronized enough for me not to notice the discrepancy) with the world’s other clocks.
But if I were to flout the posted limit, and cruise near the speed of light**, my clock would run so slowly (as others measure it) that I would time travel into the future. When my trip was over, the short time registered on my car’s clock (and in my body), would be at odds with the long time registered on others’ clocks (and in their bodies). My four-wheeled time machine would have catapulted me forward in time.
Such time travel into the future would be a kick. But it is time travel into the past that seems to spark most people’s imagination. This “backwards” time travel is not a feature of special relativity; we have no idea how it might be done. … Or do we?!
2012’s Safety Not Guaranteed is a wonderful movie that toys with this question gleefully. In it, not only do we wonder whether backwards time travel is possible, we wonder whether the movie’s two central characters really even believe it is possible!
The late Roger Ebert wrote: “Few descrip- tions of Safety Not Guaranteed will do it justice. It’s a more ambitious and touching movie than seems possible.” Other critics tend to agree; Safety Not Guaranteed is 91% “Fresh” at RottenTomatoes.
This Saturday, June 8, you are cordially invited to a special screening of Safety Not Guaranteed followed by an even more special half-hour discussion of time travel with physicist and sci-fi author Ken Wharton. Dr. Wharton is professor of physics and astronomy at San Jose State University.
As with other Wonderfest “Cinema Science” events, this one will take place at the terrific little Variety Preview Theater, within a few paces of the Montgomery Street BART station in San Francisco.
I dearly hope you will express your curiosity — and your affection for science popularization and children’s welfare — by joining the fun this Saturday evening.
* Einstein’s special relativity is called a theory only in the scientific sense of that term; it’s not just an educated guess! Like the theory of evolution and quantum theory, the special theory of relativity is supported by overwhelming evidence.
** It would take me about a year to reach such speeds — unless I didn’t mind getting squished by the “g-force” of extreme acceleration.