Sunday, 13 May 2018

Feynman at 100.

This weekend marks what would be the 100th birthday of legendary American physicist Richard P. Feynman. In a world in which many people think of the socially awkward Sheldon Cooper in the television show The Big Bang Theory as being a typical scientist, Feynman was the quite the opposite. And he should be remembered as one of the most brilliant and impactful physicists of the 20th century.
The public met him in his 1985 book Surely You're Joking Mr. Feynman, in which he regaled the reader with anecdotes of a colorful and well-enjoyed life. Feynman was a bon vivant, with an affinity for samba music, art, strip clubs and playing the bongos. He was also a successful ladies' man.
There are those who have claimed that he was sexist, but the truth is subtler. He encouraged his sister to study physics, he advocated for both male and female students, and in the 1970s he supported a fellow female faculty member who he felt had been discriminated against due to gender. (She won her lawsuit in part due to his backing.) He certainly was a product of his time, but his attitudes towards women were not unusual for the era.
Feynman was certainly one of the most brilliant scientific minds of the 20th century, with an impact eclipsed perhaps only by Einstein. He was born in Queens, New York, to immigrant parents. His advanced academic life began when he attended college at Massachusetts Institute of Technology, followed by graduate study at Princeton University, where he achieved a perfect score on the physics entrance exams. The bulk of his career was spent at Cornell University and California Institute of Technology.
His incredibly fertile mind generated many innovative ideas in physics, but his most renowned work was in helping to craft the theory of Quantum Electro Dynamics, or QED. QED is an advanced theory of electromagnetism and it incorporates quantum mechanics and Einstein's theory of special relativity. This esoteric theory explains the behavior of subatomic particles under extreme conditions and is the fundamental underpinning of all modern physics theories. It was originally formulated in 1948 by a coterie of theoretical physicists.
Feynman made many important technical additions to the theory, but probably his most impactful contribution was what are now called Feynman diagrams. Feynman diagrams are just little cartoons that show how subatomic particles interact. Basically, they are little stick figures, the simplest of which show two particles approaching one another, then one of them shoots a third particle at the other, and then both particles recoil and move off in a different direction.
The brilliance behind Feynman diagrams is that each line in the stick figure comes with an associated mathematical equation. And now that means that anybody can draw a series of these cartoons for any imagined subatomic interaction and then a sufficiently trained scientist could convert the diagrams to equations and then solve them. Certainly, Feynman diagrams made it much easier to learn this very advanced physics for me and others of my generation.
Feynman's contribution to the development of QED led to the 1965 Nobel Prize in physics, shared with Julian Schwinger and Shinichiro Tomonaga.
Feynman's ability to simplify and clarify ideas are exemplified in what are now called the Feynman Lectures. These lectures were given in 1961 -- 1963 at Caltech and are perhaps the most famous set of pedagogical physics presentations ever given. The intended audience is physics students and not casual scholars, but they are fascinating reading and well worth your time if you want to learn physics from the master.
He also served on the Rogers Commission, which investigated the 1986 Space Shuttle Challenger disaster. The Challenger exploded shortly after it launched on a cold January day. Although seriously ill with cancer, Feynman wanted to get to the bottom of the tragedy. It was suggested to him by people with technical knowledge of the engineering of the space shuttle that O-ring gaskets used to seal joints between shuttle components were not tested at low temperatures. During a televised hearing, Feynman -- who always had a flair for the dramatic -- dipped a sample O-ring in ice water and then showed that it lost its ability to seal cracks. It was eventually concluded that O-ring failure was the root cause of the loss of the Space Shuttle Challenger, along with the entire crew.
Reading of Feynman's free-wheeling life can be fun, but that's not what he was really about. Instead, his true legacy can be found in his writings, both technical and those aimed at the community of non-scientists. It might be said that his guiding principle was to seek the truth, whatever it might be, and to be open to the idea that you might be wrong. Perhaps he said it most succinctly in his essay, Cargo Cult Science. He wrote that "The first principle is that you must not fool yourself - and you are the easiest person to fool." It's a good, timely reminder for all of us.

Till next time.
Big love. Mark X