It's excellent stuff, thanks again for the info. Mind you, that's an easy chapter as there's not an integral sign to be seen anywhere.But I note they're not forgotten, they reappear in great abundance in Chapter 9! :-) In fact, I'm already half way through Chapter 8, An Attempt to Build a Physical Picture of the Quantum Nature of Matter, as it's a breeze to read it's so well written - it's not only informative but also entertaining which is a rare quality for a physics textbook. From the little I've read so far I note the way he writes forces me to think laterally, in effect he's forcing me to perceive things from a different perspective. Had he used words like 'experience' or 'influence' it wouldn't have been nearly as effective writing. Here, 'suffer' conjures up the notion of imposition - of gravity imposing an acceleration on bodies which otherwise wouldn't be the 'natural' order of things. "Thus, the laws of gravitation can be expressed as follows: Two bodies suffer a mutual acceleration, in the direction of the line adjoining them, which is inversely proportional to the square of the distance between them." Further down the same page when discussing gravity he makes a very straightforward statement but with a twist: For instance, take the 2nd para on p151 wherein he's discussing Newton's Laws of Motion and force, it's pretty hard to stop reading a paragraph that begins "It is a curiously ironical development of history that.". Still not sure how I missed this given its prominent position amongst texts on the subject.Īnyway, glancing through the book pretty much at random I've seen many phrases that tickle my fancy and pique my interest. I already have a downloaded version and I like very much what I see. The problem of the diverging energy of an electric field around a point source has a mirror in the issue around renormalization in QFT. But interestingly, the fundamental problems that those physicists were grappling with didn't exactly disappear in the quantum picture, they just got transmuted into new problems in quantum electrodynamics. In the end these problems were "resolved" because the classical picture doesn't hold on these small length scales - you need a quantum mechanical description. They imply that due to its self-force an electron can spontaneously accelerate exponentially - or, even worse, act with retrocausality and start moving before you even touch it! But the results they got were paradoxical. Moreover, when the electron radiates an electromagnetic wave, that wave will in turn impart a force to the electron, resulting in a "self-force." Calculating these self-forces and internal stresses occupied many of the brightest physicists of the early 1900s, including Poincaré. To make matters worse, if you accelerate an electron, the electromagnetic waves generated by one part of the electron will act on the other part. That means there has to be a new force acting like rubber bands to hold the thing together. If you assume that the electron is a little sphere packed with charge, what keeps it together? The self-repulsion from the electric field will try to make it explode apart. (Estimates of this size are how we get the notion of the "classical radius of the electron.") But now there was a new problem. To avoid this infinity physicists generally assumed that the electron had to have some finite radius. This works for a lot of practical problems, but by the 20th century it was known that this couldn't be the real story because if you integrate up the energy in the electric field around a point source you find that it's infinite! And with Einstein's discovery of relativity, that meant that it would be infinitely massive. In classical mechanics we approximate an electron as a point charge - an infinitesimally small source of electric charge. One of the big problems at the time was the problem of the self-force of electric fields and the structure of the electron. Physics in the early 20th century is fascinating because by this point physicists had pushed classical mechanics right to the limit of where classical physics could go and were starting to grapple with the contradictions that popped up when they went any further.
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