“I’m in charge of Los Angeles.  And I come here; I feel like a little fat girl.”

We usually think of time travel as something that happens in science-fiction movies.  Images of “Back to the Future,” “The Time Machine,” or “The Time Traveler’s Wife” come to mind.  The reality, however, is that it’s really quite common.  In fact, many of us will time travel this summer.

The above quote is spoken by Jane Fonda’s character, Chelsea, in the movie On Golden Pond (1981 )...