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Honors for Uniqueness

Einstein’s Happiest Thought

“Humpty Dumpty sat on a wall,
Humpty Dumpty had a great fall;
All the lab’s physicists and every instrument
Couldn't find gravity during the plummet.”

In 1907, a clerk in the Swiss patent office named Albert Einstein had what he considered to be the happiest thought of his life. He daydreamed about an elevator falling with a person inside. From the outside, the person and the elevator fall at the same rate. But the person inside would feel he was floating as if he was in outer space. Einstein proposed that no local experiment inside could distinguish the falling elevator from one floating in space, far from any planet. This is the famous equivalence principle.

I built a cardboard dollhouse, which I moved up and down similar to the Vomit Comet, research aircraft that simulate weightlessness. Through over forty trials, I recorded at 240 fps to capture the perfect moment when the room became weightless. The left-most dot of the accelerometer on the miniature “TV screen” reads 0.036438, indicating gravity has been reduced to only 3.6% of g. My little Humpty Dumpty therefore cannot tell if he is in outer space.

The equivalence principle set Einstein on the path to incorporating gravity into relativity. The effects of gravity can be deduced using accelerating frames. His work eventually became General Relativity, a cornerstone of physics, and led to astounding discoveries such as the expansion of the universe, black holes, and gravitational waves (ripples in spacetime).