Discussion:
Is Light Particle or Wave in Einstein's Schizophrenic World?
(trop ancien pour répondre)
Pentcho Valev
2017-05-18 15:03:44 UTC
Permalink
Raw Message
Chad Orzel: "Another not-really historical parallel that gets cited a bunch is the idea of John Michell's "dark stars" as a precursor to black holes. Michell, working in the late 1700's with Newton's corpuscular theory of light as a stream of tiny particles, theorized that light leaving massive stars ought to be slowed down by the influence of gravity... [...] Of course, Michell's idea isn't really connected to the modern notion of black holes. His reasoning (and a similar argument from his contemporary Pierre-Simon Laplace) was based on the theory of light as a particle. At the end of the 1700's, though, experiments by Thomas Young, François Arago, and Augustin-Jean Fresnel, showed pretty conclusively that light is a wave..." https://www.forbes.com/sites/chadorzel/2017/05/18/why-do-we-invent-historical-roots-for-modern-science/

Richard Feynman says light behaves like particles - if that is correct, Michell was right and light IS slowed down by the influence of gravity (this explains the gravitational redshift):

http://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170
Richard Feynman, "QED: The strange theory of light and matter", p. 15: "I want to emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you probably learned something about light behaving like waves. I'm telling you the way it does behave - like particles. You might say that it's just the photomultiplier that detects light as particles, but no, every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering the same thing: light is made of particles."

The variable speed posited by the particle theory of light is directly compatible with the null result of the Michelson-Morley experiment. The constant speed of light posited by the ether theory was incompatible with the experiment - in order to make it compatible, FitzGerald, Lorentz, Poincaré and Einstein had to introduce miracles ("contracting lengths, local time, or Lorentz transformations"):

http://books.google.com/books?id=JokgnS1JtmMC
Banesh Hoffmann, Relativity and Its Roots, p.92: "There are various remarks to be made about this second principle. For instance, if it is so obvious, how could it turn out to be part of a revolution - especially when the first principle is also a natural one? Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether. If it was so obvious, though, why did he need to state it as a principle? Because, having taken from the idea of light waves in the ether the one aspect that he needed, he declared early in his paper, to quote his own words, that "the introduction of a 'luminiferous ether' will prove to be superfluous."

Pentcho Valev
Pentcho Valev
2017-05-19 06:54:23 UTC
Permalink
Raw Message
Insofar as its speed is concerned, light behaves like particles, not like waves, both in gravitation-free space and in a gravitational field. This was obvious in 1905 but Einstein found it profitable to introduce the false constancy of the speed of light. Physicists did not protest (except for Walther Ritz) because they were all etherists and the false constancy was a tenet of the ether theory:

http://www.pitt.edu/~jdnorton/papers/companion_final.pdf
"These efforts were long misled by an exaggeration of the importance of one experiment, the Michelson-Morley experiment, even though Einstein later had trouble recalling if he even knew of the experiment prior to his 1905 paper. This one experiment, in isolation, has little force. Its null result happened to be fully compatible with Newton's own emission theory of light. Located in the context of late 19th century electrodynamics when ether-based, wave theories of light predominated, however, it presented a serious problem that exercised the greatest theoretician of the day."

http://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170
Richard Feynman, "QED: The strange theory of light and matter", p. 15: "I want to emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you probably learned something about light behaving like waves. I'm telling you the way it does behave - like particles. You might say that it's just the photomultiplier that detects light as particles, but no, every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering the same thing: light is made of particles." x

http://books.google.com/books?id=JokgnS1JtmMC
Banesh Hoffmann, Relativity and Its Roots, p.92: "Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether."

http://sethi.lamar.edu/bahrim-cristian/Courses/PHYS4480/4480-PROBLEMS/optics-gravit-lens_PPT.pdf
"If we accept the principle of equivalence, we must also accept that light falls in a gravitational field with the same acceleration as material bodies."

https://courses.physics.illinois.edu/phys419/sp2011/lectures/Lecture13/L13r.html
University of Illinois at Urbana-Champaign: "Consider a falling object. ITS SPEED INCREASES AS IT IS FALLING. Hence, if we were to associate a frequency with that object the frequency should increase accordingly as it falls to earth. Because of the equivalence between gravitational and inertial mass, WE SHOULD OBSERVE THE SAME EFFECT FOR LIGHT. So lets shine a light beam from the top of a very tall building. If we can measure the frequency shift as the light beam descends the building, we should be able to discern how gravity affects a falling light beam. This was done by Pound and Rebka in 1960. They shone a light from the top of the Jefferson tower at Harvard and measured the frequency shift. The frequency shift was tiny but in agreement with the theoretical prediction. Consider a light beam that is travelling away from a gravitational field. Its frequency should shift to lower values. This is known as the gravitational red shift of light."

http://www.einstein-online.info/spotlights/redshift_white_dwarfs
Albert Einstein Institute: "One of the three classical tests for general relativity is the gravitational redshift of light or other forms of electromagnetic radiation. However, in contrast to the other two tests - the gravitational deflection of light and the relativistic perihelion shift -, you do not need general relativity to derive the correct prediction for the gravitational redshift. A combination of Newtonian gravity, a particle theory of light, and the weak equivalence principle (gravitating mass equals inertial mass) suffices. [...] The gravitational redshift was first measured on earth in 1960-65 by Pound, Rebka, and Snider at Harvard University..."

Pentcho Valev

Loading...