Author: Richard P. Feynman
Quotes of Author: Richard P. Feynman
Another time somebody gave a talk about poetry. He talked about the structure of the poem and the emotions that come with it; he divided everything up into certain kinds of classes. In the discussion that came afterwards, he said, "Isn't that the same as in mathematics, Dr. Eisenhart?" Dr. Eisenhart was the dean of the graduate school and a great professor of mathematics. He was also very clever. He said, "I'd like to know what Dick Feynman thinks about it in reference to theoretical physics." He was always putting me on in this kind of situation. I got up and said, "Yes, it's very closely related. In theoretical physics, the analog of the word is the mathematical formula, the analog of the structure of the poem is the interrelationship of the theoretical bling-bling with the so-andso"–and I went through the whole thing, making a perfect analogy. The speaker's eyes were _beaming_ with happiness. Then I said, "It seems to me that no matter _what_ you say about poetry, I could find a way of making up an analog with _any_ subject, just as I did for theoretical physics. I don't consider such analogs meaningful. book-quoteWhat else can you do with the law of gravitation? If we look at the moons of Jupiter we can understand everything about the way they move around that planet. Incidentally, there was once a certain difficulty with the moons of Jupiter that is worth remarking on. These satellites were studied very carefully by Rømer, who noticed that the moons sometimes seemed to be ahead of schedule, and sometimes behind. {One can find their schedules by waiting a very long time and finding out how long it takes on the average for the moons to go around.} Now they were ahead when Jupiter was particularly close to the earth and they were behind when Jupiter was farther from the earth. This would have been a very difficult thing to explain according to the law of gravitation-it would have been, in fact, the death of this wonderful theory if there were no other explanation. If a law does not work even in one place where it ought to, it is just wrong. But the reason for this discrepancy was very simple and beautiful: it takes a little while to see the moons of Jupiter because of the time it takes light to travel from Jupiter to the earth. When Jupiter is closer to the earth the time is a little less, and when it is farther from the earth, the time is more. This is why moons appear to be, on the average, a little ahead or a little behind, depending on whether they are closer to or farther from the earth. This phenomenon showed that light does not travel instantaneously, and furnished the first estimate of the speed of light. This was done in 1676. book-quote
