You don’t need to fly a spaceship at nearly the speed of light to demonstrate what Albert Einstein’s theory of relativity is about. All you need is a pen.
“Is the pen between my fingers?” says Steven Gimbel, holding a pen with the thumb and pinkie of his right hand. Well, of course it is.
Gimbel is the author of the recently published Einstein: His Space and Times, and he turned his talk last month at the Jewish Community Center of Greater Washington’s Lessans Family Annual Book Festival into a love fest for the 100th anniversary of Einstein’s General Theory of Relativity.
“Now,” Gimbel says, as he grips the pen between the thumb and forefinger of his right hand and points it to the left. “Am I pointing it to the left?”
Yes. Well, no. From the audience’s point of view, the pen is pointing to the right.
There are two kinds of truth, explains Gimbel, who chairs the philosophy department at Gettysburg College in Gettysburg, Pa., and whose work focuses on the history and philosophy of science. Like many people, he has a soft spot for Einstein.
One sort of truth is called invariant truth — it’s true no matter where you’re looking from. The other — covariant truth — varies depending on the point of view of the observer, he explains.
Einstein demonstrated that properties that had been thought were invariant were not: length, mass and time all change with the point of reference. Only the speed of light remains constant.
Like the demonstration with his pen, Gimbel has another low-tech way to show how time changes as a moving object nears the speed of light. He strides down the aisle between his JCCGW lunchtime audience — a routine he likely perfected in the classroom — snapping his fingers to count off the seconds. As the audience’s watches tick off the seconds, Gimbel’s strides become slower and the time between his finger snaps steadily increases. Had it been a real demonstration, the audience would be long gone by the time Gimbel made it to the back of the room and out to the book signing.
Einstein showed that the universe has four dimensions, he says. But people are equipped for only three of them.
Why do Jews love Einstein so much?
“Everyone likes Einstein,” he says. “But Jews, we really love Einstein. Why is it that we hold him up as the pinnacle of our people, when for most of his life he denied the fact that he was Jewish?”
Gimbel points to 1915 and the reception in Germany to the theory of relativity as the beginning of Einstein’s identification with Judaism. His groundbreaking work, done in the spirit of rational inquiry, was denounced by anti-Semites as “Jewish science,” says Gimbel, whose book Einstein’s Jewish Science was published in 2012.
He describes a conversation Einstein had with the Jewish philosopher Martin Buber on “what makes us Jewish.” The two prewar giants of thought — one a rational physicist, the other a student of Chasidism — said it is Judaism’s “ethic based on empathy” and its sense of “awe, joy and wonder when discovering the universe” that makes them Jewish.
Says Gimbel, “That’s how he came to readopt and reassume his Judaism.”