Feynman's The Character of Physical Law 1

The second half of June is often the season when administrators take what they can of their remaining vacation days, so I am relaxing a bit these next two weeks (though I am happily and gratefully continuing to work for the Seminary until the end of August).

1. So this morning I picked up an old book of interest to me by Richard Feynman, The Character of Physical Law. I make no promises to finish it, but I read the first chapter this morning.

Feynman was a curious soul. I blogged through the first eight chapters of a biography of him last summer, then stopped when the school year came on heavy. Perhaps I will try to finish working through it. I am cursed with too many interests, too little intellect, and too little time. I wish there was a chamber you could enter where time outside freezes but you can go in and study for a while.

Einstein-Dirac-Feynman-Hawking--that's my current list of the greatest geniuses of twentieth century physics. Feynman gave these lectures in 1965 at Cornell.

2. Chapter 1 is about the law of gravitation, first set down by Newton. I'm not sure what to expect from this book. I'm looking for some insight behind physical law. My hunch is that Feynman will not be able to tell me. My hunch is that he is going to muse about patterns, scientific development, and curious correspondences. But there are no real answers to why the laws of nature work the way they do.

He mentions some of these mysteries in this chapter. So the inverse square of distance seems to have some deep significance, but we don't know what it is (30). It shows up both in the law of universal gravitation and in the formula for electric charge. But the relationship between these two forces is unknown and different on the level of 10 to the 42nd power (a one with 42 zeros after it).

Newton's law of gravitation also had to be modified a little by Einstein, who with the help of David Hilbert set out a general theory of relativity that included gravity. Yet even here, Feynman noted that this theory could not yet account for gravity on the quantum level. This is one of the cutting edges of physics.

Feynman ends this first lecture with three observations.

a. The first is the correspondence between physical reality and mathematics. I've mentioned the inverse square feature.

A fun story in the chapter is when two individuals using only math and the observed movements of Uranus independently asked two different observatories to turn their satellites toward a part of the sky where they expected to find a planet, Neptune. The rationale was the hypothesis that Uranus' orbit was being affected by another large planet.

Feynman's account is different from others. He basically suggests that the British observatory thought it ridiculous that you could find a planet by math, while the German observatory dutifully looked and found. This is probably a better story but perhaps less true.

b. The second observation is that these discoveries are not exact, as in the need for modification by Einstein and still by someone in relation to quantum gravity.

c. The third, though, is the simplicity of Newton's basic equation and fourthly its universal character.

3. In the meantime, the chapter gives a lovely tale of how the law developed from Copernicus to Kepler and Galileo to Newton to Cavendish and several other scientists up till the twentieth century. A reassuring reminder is that it took some four centuries to unfold the content of this chapter and that these scientists worked a lifetime on them. They seem amazingly brilliant after the fact, and no doubt they were.

But they weren't brilliant every day. We tend to miss the trial and error of their probings and the long story of development.

P.S. I forgot to mention the old idea around the time of Galileo that angels pushed the planets around. (Feynman had a flair for the dramatic, so I probably should confirm this) He suggests that this is not entirely wrong, but that they were wrong on the direction in which the angels were pushing. The angels--gravity--were pushing inward toward the sun rather than pushing behind the planet. After all, a body in motion stays in motion all by itself... another mystery whose reasons we know not why.