Discussion:
Light Tangent to Earth's Surface Curves as per Einstein or as per Newton?
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Pentcho Valev
2021-04-07 22:50:48 UTC
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Question: "If a light beam is sent tangent across earth would it curve at 9.8 m/s^2?" https://physics.stackexchange.com/questions/627464/if-a-light-beam-is-sent-tangent-across-earth-would-it-curve-at-9-8-rm-m-s2/627496

MY ANSWER: "Yes the light beam would curve at 9.8 m/s^2, as per Newton's theory":
"To see why a deflection of light would be expected, consider Figure 2-17, which shows a beam of light entering an accelerating compartment. Successive positions of the compartment are shown at equal time intervals. Because the compartment is accelerating, the distance it moves in each time interval increases with time. The path of the beam of light, as observed from inside the compartment, is therefore a parabola. But according to the equivalence principle, there is no way to distinguish between an accelerating compartment and one with uniform velocity in a uniform gravitational field. We conclude, therefore, that A BEAM OF LIGHT WILL ACCELERATE IN A GRAVITATIONAL FIELD AS DO OBJECTS WITH REST MASS. For example, near the surface of Earth light will fall with acceleration 9.8 m/s^2." http://web.pdx.edu/~pmoeck/books/Tipler_Llewellyn.pdf

AN EINSTEINIAN'S ANSWER: "Yes it will curve, but not at 9.8 m/s^2 as predicted by Newton's theory. Its curvature will be twice that value as predicted by General Relativity."

Who is right?

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Pentcho Valev
mitchr...@gmail.com
2021-04-07 23:01:16 UTC
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Post by Pentcho Valev
Question: "If a light beam is sent tangent across earth would it curve at 9.8 m/s^2?
Light is too close to straight as by it's parabola open curve motion...

Mitchell Raemsch
JanPB
2021-04-08 02:43:43 UTC
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Post by Pentcho Valev
Question: "If a light beam is sent tangent across earth would it curve at 9.8 m/s^2?" https://physics.stackexchange.com/questions/627464/if-a-light-beam-is-sent-tangent-across-earth-would-it-curve-at-9-8-rm-m-s2/627496
"To see why a deflection of light would be expected, consider Figure 2-17, which shows a beam of light entering an accelerating compartment. Successive positions of the compartment are shown at equal time intervals. Because the compartment is accelerating, the distance it moves in each time interval increases with time. The path of the beam of light, as observed from inside the compartment, is therefore a parabola. But according to the equivalence principle, there is no way to distinguish between an accelerating compartment and one with uniform velocity in a uniform gravitational field. We conclude, therefore, that A BEAM OF LIGHT WILL ACCELERATE IN A GRAVITATIONAL FIELD AS DO OBJECTS WITH REST MASS. For example, near the surface of Earth light will fall with acceleration 9.8 m/s^2." http://web.pdx.edu/~pmoeck/books/Tipler_Llewellyn.pdf
AN EINSTEINIAN'S ANSWER: "Yes it will curve, but not at 9.8 m/s^2 as predicted by Newton's theory. Its curvature will be twice that value as predicted by General Relativity."
Who is right?
See more here: https://twitter.com/pentcho_valev
Pentcho Valev
Junk posts.

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Jan
Lee Aecca
2021-04-08 10:42:16 UTC
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See more here: https://twitter.com/pentcho_valev Pentcho Valev
Junk posts.
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Fauci, not italian, is saying covid *_ass_masks_* are needed, mandated
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That's why lying is exponentially worse than killing.

Type "who is the most powerful doctor" in google, then read which
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Cliff Hallston
2021-04-08 02:48:28 UTC
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Post by Pentcho Valev
Question: "If a light beam is sent tangent across earth would it curve at 9.8 m/s^2?"
Acceleration is not the same thing as "curvature" (of the path), and neither of those is the same as the total angular deflection between the incoming and outgoing asymptotes, which is what we observe. Also, the values of acceleration and angular "curvature" of the path (not to be confused with intrinsic curvature of the manifold) are both coordinate-dependent, so we need to specify our coordinates when answering a question like this.

In terms of Schwarzschild coordinates, the rate of deflection at the tangent point does indeed correspond to a radial acceleration of 9.8 m/sec^2, in both the 1911 calculation and the final 1915 theory of general relativity. The doubling of the overall angular deflection between the asymptotes in the 1915 theory arises from a greater deflection rate as the ray gets further from the tangent point and acquires some radial velocity. In terms of isotropic coordinates, which are conformal, the distribution of angular deflection is different, due to the different radial coordinate, but of course the equivalence principle is still satisfied and the net asymptotic deflection is the same.
Pentcho Valev
2021-04-08 12:11:47 UTC
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"Any sign that general relativity is wrong...would revolutionize physics." https://science.sciencemag.org/content/371/6525/116

It is OBVIOUSLY WRONG. The speed of light falling in gravity varies as per Newton (proved by the Pound-Rebka-Snider experiment), which implies that gravitational time dilation does not exist:

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." https://courses.physics.illinois.edu/phys419/sp2011/lectures/Lecture13/L13r.html

Albert Einstein Institute: "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..." http://www.einstein-online.info/spotlights/redshift_white_dwarfs.html

"We conclude, therefore, that A BEAM OF LIGHT WILL ACCELERATE IN A GRAVITATIONAL FIELD AS DO OBJECTS WITH REST MASS. For example, near the surface of Earth light will fall with acceleration 9.8 m/s^2." http://web.pdx.edu/~pmoeck/books/Tipler_Llewellyn.pdf

R. V. Pound and J. L. Snider, Effect of Gravity on Gamma Radiation: "It is not our purpose here to enter into the many-sided discussion of the relationship between the effect under study and general relativity or energy conservation. It is to be noted that no strictly relativistic concepts are involved and the description of the effect as an "apparent weight" of photons is suggestive. The velocity difference predicted is identical to that which a material object would acquire in free fall for a time equal to the time of flight." http://virgo.lal.in2p3.fr/NPAC/relativite_fichiers/pound.pdf

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