# An untold tale about Richard Fyneman

When I was at Caltech, Richard Fyneman, the renowned physicist, gave a one-hour seminar each week entitled Physics X. It was not in the catalogue. There was no college credit. You just showed up in the lecture hall and Fyneman would ask, “OK, what shall we discuss today?”

He was a great lecturer. With no preparation ahead of time, he would explain some hard to understand aspect of physics that was wonderfully clear. You took notes furiously, because a half-hour or so after leaving the hall, the brilliant insight that you thought you now grasped would begin to fade.

I remember to this day that one time on of us sitting in the audience said something like the following:

“Professor Fyneman, suppose you are in a spaceship going very nearly the speed of light. You are flying parallel to a long mirror extending far into space alongside you. You look out and see your reflection in the mirror.

“Now it take some time, not much, but some time for the light from your spaceship to travel to the mirror and then bounce back to you. This means that the reflection will not be exactly aligned but lag behind slightly. Since you, yourself, are going so swiftly, the angle would be noticable. You would have to crane your neck to see your reflection.

“So by measuring the angle of the lag, you could then figure out how fast you are going, and that would violate Special Relativity.”

“An interesting problem,” Fyneman said and retreated to the long blackboard behind him. He drew a chalk line from left to right and turned to smile at us, “That is the mirror,” he said. Then somewhere in the middle of the board, he drew a little crude spaceship, a beam of light exiting from it and the reflection coming back.

Then he calculated for a few minutes and presented the results of his calculation, an equation for what the angle would be as a function of how fast the spaceship was moving.

“Very good, young man, you are right. You can tell how fast you are going. Special Relativity is wrong.”

There was a stunned silence. How could this possibly be? Special Relativity was a fundamental cornerstone of physics. It had been around for almost sixty years. Validated by scores if not hundreds of independent experiments by the greatest minds in the world. How could an undergrad, a freshman no less, come up with a thought experiment that crashed everything down?

For a few moments, no one dared speak. Then Fyneman cocked his head to the side and returned to the board. He corrected one of his intermediate equations, fixed up the results and turned back to address us. I made a simple error. The angle is independent of the spacecraft’s speed. Special Relativity is saved.”

Everyone laughed at what had just transpired. Of course, no freshman was going to bring all of physics crashing down. If I or anyone else in the room had come up with the formula for what the lag angle would be, we would have checked our work probably a dozen times before making any pronouncements to a room filled with other (aspiring) physicists.

On further thought, what had happened was pure Richard Fyneman. The utter unlikelihood of a freshman coming up with something that would completely upset all of physics must have never entered his mind. Instinctively, he just followed where the equations were leading him. And to me, that was an example of what it took to make true breakthroughs, to be a Nobel Prize winner – ignore the shackles that constrain our thinking onto paths that have been traveled many times before. Who knows what wondrous thoughts might then result.

© 2016 Lyndon M. Hardy

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## 2 thoughts on “An untold tale about Richard Fyneman”

1. Excellent thought and excellent example, I’m a 47 year old engineer and have always questioned the known rules.

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