TheSecondCreation

The Second Creation (Robert Crease and Charles Mann)

  • Decent overall, a little to popular for my taste. Good backstories I haven't heard elsewhere.
  • Few general readers have absorbed the news that within living memory, physicists have written equations that can accurately predict the outcome of every fundamental process in nature. It is as if the average citizen of Renaissance Florence had never seen a ceiling fresco.
  • When the SM fell into place, it did so all at once, after much disorder. Physicists who had expected to spend their careers straightening up a small corner of the immense arena of their incomprehension found themselves closer to their goal than they had ever dreamed.
  • Rutherford thought that the constituents of the atom would not be found "in this generation or the next and probably not completely for many years, if at all, or for many hundreds of years."
  • The SM was pieced together by three distinct intellectual generations of 20C physicists.
    • QM mid 20s: Heisenberg, Pauli, Oppenheimer, Rabi, Schrodinger and Jordan
    • 40-50s: predominantly American
    • 70s:
  • Mathematics can lead us in a direction we would not take if we only followed up physical ideas by themselves.
  • The magnetic moment of the electron, from Dirac's relativistic theory, was something that no non-relativistic theory could describe. It was a fundamentally relativistic phenomenon, and to be told that a) the physical answer was not what Dirac's theory gave and b) that there was no simpleminded way of thinking about it, that was the real challenge.
  • Electroscope: a device consisting of two little strips of metal foil hanging like two stiff flags from a central rod. When the electroscope is charged up near some uranium, the conductivity of the air around the two strips causes them to discharge, and their ends fall back together. Scientists realized that this effect made it possible to press electroscopes into service to measure radioactivity. Early radioactivity buffs had found, however, that their instruments "leaked" slowly discharging even when no uranium was around.
  • Hess's ideas were greeted with derision. The idea that interstellar rays were continually bombarding the earth with enough strength to shoot through several feet of lead was too wild for many scientists.
  • The trick of using Geiger counters to trigger cameras was invented in 1932 by Blackett and Occhialini.
  • Japanese Army command asked Nishina, Yukawa's mentor, to tour Hiroshima to decide if Truman's claim that there was an atom bomb was correct.
  • The whole infinity cancellation would only work if the theory was limited to be just the original, simplest possible QED. If you tried to muck around with QED, then the whole application of renormalization would break down. You just couldnt do it.
  • Symmetry plays two roles:
    • often it is the thing to thing about b/c its the only way you can make progress.
    • it is the thing that drives the dynamics (eg: Yang-Mills and GR) It is the central problem.
  • If you have an elementary particle and you describe how it behaves under various symmetry transformations, then you've said everything there is to say about the particle. The identity of the particle is fixed by its symmetry properties.
  • The electric charge of an electron never changes. The reason the phase can shift and not affect the charge is b/c of the gauge symmetry, which compensates for such changes by creating virtual photons and hence and EM field whose actions ensure the conservation of electric charge.
  • "I do not believe that the Lord is a weak left-hander and I am ready to bet a very large sum that the experiments will give symmetric results." - Weisskopf
  • "America is the place you do things. Its important to get on with the job instead of setting up committees to study the best possible way."

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