I have a feature article in this month's issue of Physics World magazine, "The 10 greatest predictions in physics." The version in the magazine has a better design, but here's the free version they offer.
David Appell highlights theoretical physics predictions that have rocked our understanding of how the world works @davidappell @PhysicsWorld #geekingOut https://t.co/YZ14rTctsi— Michael Njenga (@michaelnjenga) January 21, 2021
David Appell highlights theoretical physics predictions that have rocked our understanding of how the world works @davidappell @PhysicsWorld #geekingOut https://t.co/YZ14rTctsi
I enjoyed that because I learnt something new. Thank you.
The Poisson and Hoyle predictions are especially interesting. The first because it's such a school book example on how science is supposed to work with finding unexpected consequences of a new theory, making a prediction and then rapidly making an experiment to verify it. The fact that Poisson didn't believe his own prediction is icing on the cake. The second because it was such a backwards and creative way to reason.
Thanks Thomas. Though it wasn't really Poisson's prediction, it was Fresnel's, which Poisson doubted -- which just made the story better.
Thanks Ian, I really appreciate your comment.
David, Fresnel made the theory, but the prediction of a bright spot in the middle of the shadow was from Poisson, a failed attempt at reductio ad absurdum.
Thomas: I think Fresnel made the prediction, but Poisson noted it explicitly and then doubted it....
Very nice article!cheers
Great article David! In particular, I liked the Hoyle story. I was wondering what other predictions you were considering that didn't quite make it into the top ten?
Thanks for all the comments, everyone, I appreciate it.JoeT, really appreciate yours. I originally wrote a "Second 10" Honorable Mentions, which my editor cut because of space. I think Physics World is going to do a podcast about this article, and I hope to talk more about other predictions then. Here were my honorable mentions -- what do you think?11. Urbain Le Verrier, prediction of Neptune (1846)12. James Clerk Maxwell, prediction that the rings of Saturn could not be solid (1856)13. Albert Einstein, equivalence of mass and energy, E=mc2 (1905)14. Albert Einstein, gravitational waves (1915)15. Wolfgang Pauli, existence of the neutrino, ν (1930) 16. Subrahmanyan Chandrasekhar, Chandrasekhar limit (1930)17. Paul A.M. Dirac, existence of the positron, e+ (1931)18. Hideki Yukawa, existence of pions, π0, π± (1935)19. John Stuart Bell, Bell’s Theorem (1964)20. John Bardeen, Leon Cooper, and John Robert Schrieffer, BCS theory -- predictions of known and new phenomena in superconductivity (1957)
BTW, a long time ago I wrote a feature for New Scientist about the Fred Hoyle story"Of Dumbbells and Doughnuts," New Scientist, May 1, 1999, p. 35.but I can't find a copy online anywhere, or in their archives. Maybe I have a hardcopy in a box somewhere, and if I find it (I'm cleaning out some old boxes now) I'll post it.
What I like about these lists is that some of them I'm not even familiar with -- such as Maxwell and Saturn. Nice one! I was also thinking of time dilation by Einstein. It shows up even in GPS satellites.Another one is CMB, for which Penzias and Wilson got the Nobel in '78. I was trying to remember if the theory was by Dicke or Gamow. It turns out maybe the answer is neither. Victor Alpher claims his father Ralph Halper together with Robert Herman, both were Gamow's graduate students, deserve the credit: https://physicstoday.scitation.org/doi/10.1063/PT.3.2859I always liked the story of how pissed Halper was that Gamow put Bethe on a paper just so he could have fun with Greek letters. Halper figured Bethe (and Gamow) would get all the credit.Finally, back in the day when I first thought I needed to learn some climate science, I was amazed that I had never heard of Milankovitch before. I was impressed that Hays, Imbrie and Shackleton published in 1976 (Figure 4, if I remember) their FFT that showed Milankovitch's prediction of some 50 years earlier was correct.
Sorry, I meant Alpher of course. Not Halper ....
Joe, you're right, the CMB prediction belongs in the top 20. I originally had it on my list of the top X, but somehow, I'm not sure how, it slid off. My editor wanted me to include a few women in the top 10 -- I didn't consider that at first, but then I'm an old white guy, and she has her own concerns -- hence I choose Mayer and Rubin, which I was fine with. Rubin wasn't exactly a prediction in the same sense as the others, more of a deduction, but so important it was hard to overlook. So somewhere in all this the CMB prediction slipped out of the top 20. My mistake.For some reason Maxwell's prediction about the rings of Saturn has always been a favorite of mine. I even have a 75-page book or so containing the proof, available from Amazon, which someday I hope to completely work through. Time dilation is definitely important, yes. Also, part of the GPS problem relies on gravitational redshift from general relativity, I think. That is, getting GPS right involves both special relativity and general relativity.Einstein was just such a genius, it's difficult to fully grasp.BTW, the podcast I mentioned isn't going to happen, alas.
PS: Love the story about the Alpher, Bethe, Gamov paper.
Joe, I didn't know about the 1976 Hays, Imbrie and Shackleton paper. Thanks!https://science.sciencemag.org/content/194/4270/1121/tab-pdf
Thanks for the comments, David. I was trying to find your New Scientist article about Fred Hoyle, but was unsuccessful. If you do find it, post it. I'd like to read it.I find the story behind the ice ages very intriguing with regard to both the prediction and the subsequent confirmation from the data. Milankovitch was arrested as a Serbian national during WWI, sits in his prison cell and calculates solar insolation at different times of the year. And the singular contribution of Harold Urey in obtaining paleotemperatures. The world's expert on isotopes, received the Nobel for discovering deuterium, developed isotope separation techniques to develop a bomb during WWII and finally understood that the relative abundances of oxygen isotopes could yield a clue about the temperature in the past. A great story. I think it should rank up there with the top 20 at least.
The story about when Einstein proved that gravitational waves couldn't exist is more fun, especially his reaction to getting the paper refused for publication, propbably a first for him.Maybe Alfred Wegener should fit in somewhere for his prediction of continental drift.
Hey Thomas, great comment about Einstein and gravitational waves. I never heard of this before, but found that Physics Today had a nice article on it with a guess as to who the anonymous reviewer was that rejected the Einstein paper.https://physicstoday.scitation.org/doi/10.1063/1.2117822And I've been corrected by the great climatologist Rand Paul as to who actually predicted the cause of the ice age cycles. Turns out it these are the 'Milosevic' cycles. No doubt this was work done by Slobodan in his spare time while on trial at the Hague. After all, as Rand puts it, "I really worry about our freedoms".https://twitter.com/i/status/1354229248907763714
Thomas, what story about Einstein proving gravitational waves couldn't exist?
Rand Paul strikes me as one of those dumb educated people. Same for Ben Carson. Seems to think that because he knows a little he therefore knows everything.
David, JoeT just gave a nice link. Even a genius makes the occasional mistake. Every scientist has bloopers like that, it's just more spectacular when it's Einstein or one of the other superstars. At least Einstein quickly realized his mistake, there are other scientists like Hoyle with steady-state or Lindzen with his iris hypothesis who never give up, even when they are wrong.
I see now, thanks. That's a good story.I wonder if anyone has ever proved that the full Einstein's equations have a plane wave solution, that is, not the linearized version of his equations. I've only ever seen the proof for the linearized version, to first order in the strain parameter h. We know now that gravitational waves exist, but what is really known is that what's observed matches what the linearized equations predict. If LIGO found something the linearized equations didn't predict they may disregard it as noise and not recognize it's a gravitational wave. Such a wave could arise from something in the very strong gravitational regime, like at the very last millisecond or less of two massive objects colliding as they spiral in to one another. Just wondering.
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