What is gravity? Part 3: The equivalence principle revisited
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CORRECTION: As an example of the above NOTE, after publication of the previous issue the last sentence of the second paragraph, critical to the piece, was revised to:
A possibly novel, if academic, application could be to remove sufficient heat from an object (small delta?E) such that the interval between ticks of a clock close by increases enough (large delta t) to form a black hole.**
To be clear, the "small delta E" arises because of proximity to absolute zero temperature.
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From Part 2 of this sequence:
"...?the question was asked, "What is gravity?" but not explicitly answered. Actually, the explicit answer, or sufficient information for one, is in the article. Regarding the theme, which is not the current consensus view, here is the completed final sentence:?It might be that dark matter is dark energy at smaller scales, dark energy is accelerated expanding space, and?accelerated expanding space is gravity. Or: Gravity is fundamentally repulsive and identical to accelerated expanding space. Either sentence preserves the equivalence principle of general relativity ... This goes beyond the equivalence principle, suggesting the identity of acceleration and gravity; "equivalence" is less restrictive, allowing for certain, possibly unknown, conditions to void the equivalence."
The following discusses this "certain, possibly unknown, conditions to void the equivalence."
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The equivalence of acceleration and gravity was noticed by Einstein under humble circumstances. As mentioned, a person fell from a height onto something that broke the fall, so that it was noted the victim felt no forces on the way down. Since he was accelerating, and the Earth was close by, it was hypothesized that acceleration and gravity were equivalent, i.e., two things (acceleration and gravity) equal to the same thing (no forces) are equal to each other. Various scenes and tests verify the hypothesis that these two very different physical concepts have not yet been distinguished. This insight is the foundation of general relativity, so that the monumental mathematical superstructure is based on this observation. Yet the equivalence principle is not taken at face value in one key instance. The acceleration of the Universe.
Why? Because gravity is "always attractive," and never repulsive like this universal acceleration. Recall, though, that general relativity was devised to seamlessly coincide with Newtonian gravity in the limit, and this classic form had this "always attractive" character imprinted by Newton in the publication. This is the view of a Seventeenth Century scientist, who did not have the benefit of present day technology; Einstein as well had this prejudice; scale was not taken into account on developing the mathematics of general relativity. To this day gravity is considered universally attractive, even with the paradigm of curved space. It is assumed that negative mass is implied with repulsive gravity. But clusters of galaxies have positive mass, and they accelerate away from one another. Repulsive gravity is not necessarily about negative mass, and it is imprudent to discount it out of hand, replacing it without a second thought with the label of "dark energy." (An approach to reconciling attractive and repulsive gravitational effects has been previously discussed.)
Then possibly at the large scale -- according to the equivalence principle of general relativity -- gravity is repulsive. But then the apparent contradiction. Gravity appears attractive at scales below galactic superclusters. Is this really a contradiction, or a clue for an opportunity -- to make the cosmological constant implicit to general relativity instead of it remaining a placeholder to make the equation conform to observation.
The equivalence principle was composed from an observation in a small corner of a galaxy on a small planet. Why should it be universal? The universal case is repulsive, suggesting the identity of acceleration and gravity. The special case results in the need for an unknown placeholder in the equation.
Assuming the mathematical superstructure of general relativity is exact, the foundation -- the equivalence principle -- must be inexact, and a possible impediment to unification with quantum theory.
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* credit: How Einstein Became the First Science ... nytimes.com
** https://www.dhirubhai.net/pulse/can-black-hole-form-from-too-little-well-much-warren-frisina/?trackingId=1w6cV%2FZQQIix8YqS9Ww7kQ%3D%3D
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3 年Gravity and acceleration are not the same thing. The two-way interaction between the curvature of spacetime and energy is a better definition for gravity. An object's acceleration refers to changes in velocity, one of which may be caused by gravity. Using Einstein's 'equivalence' principle has created confusion I think. Examine a small area in spacetime, where special relativity reigns. That little place appear flat, so therefore there is no gravity? (Since gravity is curved spacetime). A modest local measurement will not yield the source or cause of acceleration, whether gravity or something other than gravity. The equivalence principle is not saying gravity and acceleration is tautological, it is saying you simply cannot see past your little box being examined to whether: 1) the box is accelerating from the surface of the earth DUE to gravity, or out in space (no gravity) some other perhaps unknown exogenous force is the source of the acceleration.
Mgr. ve spole?nosti Physics, Astronomy, Nuclear Physics, Elementary particles, High energy physics
3 年Warren Frisina You wrote: "Assuming the mathematical superstructure of general relativity is exact...." It's a bad assumption. Why? Nobel laureates in physics are mostly physicists, who mainly create and defend physics. Einstein never received a Nobel prize for relativity... For nearly 100 years ago have been Nobel Prize winners said: "- The theory of relativity is a mathematical and not a physical theory." FACTS (1919 - 1920) : Professionally non educated EDITORS ( non physicists ) and private owners of newspapers perpetrate really serious?immoral act in science by that it hinders its natural development and creating?an??deceitful picture of Albert Einstein by his glorification: ?12 In 1919 it had carried an article [13?autor Alexander Moszkowski (1851-1934), 15 editor-in-chief was Arnold Berliner (1862-1942)]?announcing the results of the British solar eclipse expedition that rose to laudatory hyperbole, not shying away from declaring that “a highest truth, beyond Galileo and Newton, beyond Kant” had been unveiled by “an oracular saying from the depth of the skies.” 16 on December 14, 1919, the front page of the Berliner Illustrirte Zeitung [17 This newspaper had been founded by Leopold Ullstein (1826-1899)]?carried a large close-up portrait of Einstein whose caption read: “A new eminence in the history of the world: Albert Einstein, whose researches signify a complete revolution of our understanding of Nature and whose insights equal in importance those of a Copernicus, Kepler, and Newton.”? 2 The huge public acclaim that was accorded Einstein.?It also vexed conservative academics (e.g. the Nobel Laureate Philipp Lenard have felt that the theoretical physicist Einstein had captured too much of the limelight, while other, experimental physicists?were not appreciated enough.) FACTS Then followed (1920): Reactionaries and Einstein's Fame: “German Scientists for the Preservation of Pure Science,” Relativity, and the Bad Nauheim Meeting? Jeroen van Dongen Einstein Papers Project California Institute of Technology Pasadena CA 91125, USA Institute for History and Foundations of Science Utrecht University P.O. Box 80.000 3508 TA Utrecht, the Netherlands Two important and unpleasant events occurred in Albert Einstein’s life in 1920: That August an antirelativity rally was held in the large auditorium of the Berlin Philharmonic, and a few weeks later Einstein was drawn into a tense and highly publicized debate with Philipp Lenard on the merits of relativity at a meeting in Bad Nauheim, Germany. 73 Nonetheless, tensions had been mounting. Max Planck was firmly in the chair, but prior to the debate--because he was still not certain whether Einstein would remain in Berlin--he appeared to be quite agitated. 74 Paul Weyland also was present at the debate--but this time he kept a low profile. Einstein and his wife Elsa were strongly affected by the exchange: Elsa suffered a nervous breakdown. ? ?75 The Viennese experimental physicist Felix Ehrenhaft (1879- 1952) recalled that he had to take a highly upset Einstein out for a calming stroll in the park after the debate. Later that evening they avoided the uneasy company of their fellow physicists. 76 Both Lenard and Einstein left the conference deeply distressed. Lenard renounced his membership in the DPG--and even denied admittance to his office at the University of Heidelberg to any of its members. ? Albert Einstein und Philipp Lenard? Dr. Charlotte Sch?nbeck P?dagogische Hochschule Heidelberg Fakult?t für Mathematik und Naturwisse Change QUALITY ? Einstein′s theory Tkin =mc^2 – mo c^2 ? 1996: Tkin id =mc^2 [ln |1-v/c|+ (v/c) / (1-v/c) ]?NEWTON′S ? Tkin ad = mc^2 [ln |1+v/c|- (v/c) / (1+v/c) ]?MAXWELL′S ? Einstein's works?only for v < 0.1c. ? https://www.trendsinphysics.info/data/New-Trends-in-Physics-Extraordinary-proofs.pdf ? ? https://www.researchgate.net/search?q=Lubomir%20Vlcek and https://tuke.academia.edu/LubomirVlcek or https://vixra.org/author/lubomir_vlcek ? https://www.trendsinphysics.info/ ORCID:?https://orcid.org/0000-0002-0699-0012
Mgr. ve spole?nosti Physics, Astronomy, Nuclear Physics, Elementary particles, High energy physics
3 年The equivalence of acceleration and gravity is bad idea. Why? Nobel laureates in physics are mostly physicists, who mainly create and defend physics. Einstein never received a Nobel prize for relativity... For nearly 100 years ago have been Nobel Prize winners said: "- The theory of relativity is a mathematical and not a physical theory." FACTS (1919 - 1920) : Professionally non educated EDITORS ( non physicists ) and private owners of newspapers perpetrate really serious?immoral act in science by that it hinders its natural development and creating?an??deceitful picture of Albert Einstein by his glorification: ?12 In 1919 it had carried an article [13?autor Alexander Moszkowski (1851-1934), 15 editor-in-chief was Arnold Berliner (1862-1942)]?announcing the results of the British solar eclipse expedition that rose to laudatory hyperbole, not shying away from declaring that “a highest truth, beyond Galileo and Newton, beyond Kant” had been unveiled by “an oracular saying from the depth of the skies.” 16 on December 14, 1919, the front page of the Berliner Illustrirte Zeitung [17 This newspaper had been founded by Leopold Ullstein (1826-1899)]?carried a large close-up portrait of Einstein whose caption read: “A new eminence in the history of the world: Albert Einstein, whose researches signify a complete revolution of our understanding of Nature and whose insights equal in importance those of a Copernicus, Kepler, and Newton.”? 2 The huge public acclaim that was accorded Einstein.?It also vexed conservative academics (e.g. the Nobel Laureate Philipp Lenard have felt that the theoretical physicist Einstein had captured too much of the limelight, while other, experimental physicists?were not appreciated enough.) FACTS Then followed (1920): Reactionaries and Einstein's Fame: “German Scientists for the Preservation of Pure Science,” Relativity, and the Bad Nauheim Meeting? Jeroen van Dongen Einstein Papers Project California Institute of Technology Pasadena CA 91125, USA Institute for History and Foundations of Science Utrecht University P.O. Box 80.000 3508 TA Utrecht, the Netherlands Two important and unpleasant events occurred in Albert Einstein’s life in 1920: That August an antirelativity rally was held in the large auditorium of the Berlin Philharmonic, and a few weeks later Einstein was drawn into a tense and highly publicized debate with Philipp Lenard on the merits of relativity at a meeting in Bad Nauheim, Germany. 73 Nonetheless, tensions had been mounting. Max Planck was firmly in the chair, but prior to the debate--because he was still not certain whether Einstein would remain in Berlin--he appeared to be quite agitated. 74 Paul Weyland also was present at the debate--but this time he kept a low profile. Einstein and his wife Elsa were strongly affected by the exchange: Elsa suffered a nervous breakdown. ? ?75 The Viennese experimental physicist Felix Ehrenhaft (1879- 1952) recalled that he had to take a highly upset Einstein out for a calming stroll in the park after the debate. Later that evening they avoided the uneasy company of their fellow physicists. 76 Both Lenard and Einstein left the conference deeply distressed. Lenard renounced his membership in the DPG--and even denied admittance to his office at the University of Heidelberg to any of its members. ? Albert Einstein und Philipp Lenard? Dr. Charlotte Sch?nbeck P?dagogische Hochschule Heidelberg Fakult?t für Mathematik und Naturwisse Change QUALITY ? Einstein′s theory Tkin =mc^2 – mo c^2 ? 1996: Tkin id =mc^2 [ln |1-v/c|+ (v/c) / (1-v/c) ]?NEWTON′S ? Tkin ad = mc^2 [ln |1+v/c|- (v/c) / (1+v/c) ]?MAXWELL′S ? Einstein's works?only for v < 0.1c. ? https://www.trendsinphysics.info/data/New-Trends-in-Physics-Extraordinary-proofs.pdf ? ? https://www.researchgate.net/search?q=Lubomir%20Vlcek and https://tuke.academia.edu/LubomirVlcek or https://vixra.org/author/lubomir_vlcek ? https://www.trendsinphysics.info/ ORCID: https://orcid.org/0000-0002-0699-0012