Changes

Predictions of general relativity turn out to be obscure and difficult to test.  The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.

Predictions of general relativity turn out to be obscure and difficult to test.  The two most famous predictions were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.

*The first of these was famously tested during a total eclipse in 1919.  That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used.<ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>  The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome.  His analysis techniques would not pass muster today.  The announcement of this test, flawed though it was, popularized Einstein and he was awarded the [[Nobel Prize]] within a few years, but not for this.<ref>[http://einstein.stanford.edu/Library/images/lightsAllAskewBig.jpg The New York Times, Nov. 10, 1919]</ref><ref>[https://www.worldbooklearning.com/how-did-an-eclipse-help-make-albert-einstein-famous/ How did an eclipse help make Albert Einstein famous]</ref><ref>[https://blog.supplysideliberal.com/post/44934715350/how-albert-einstein-became-a-celebrity How Albert Einstein became a celebrity]</ref><ref>[https://www.sciencealert.com/general-relativity-experiment-confirms-accuracy-for-galaxies "The public's mind was blown by the results, effectively turning Albert Einstein into a household name and cementing the concept of general relativity into physics books."]</ref>

*The first of these was famously tested during a total eclipse in 1919.  That test was somewhat muddled by an incorrect initial calculation, by several people including Einstein himself, of what the effect would be, and some "cherry picking" of the data to be used.<ref>''Einstein's Luck'', John Waller, Oxford University Press, ISBN 0-19-860719-9</ref>  The data selection could be considered "manipulation" or "fudging", by a person (Arthur Eddington) who had a personal stake in the outcome.  His analysis techniques would not pass muster today.  The announcement of this test, flawed though it was, made Einstein world-famous.<ref>[http://einstein.stanford.edu/Library/images/lightsAllAskewBig.jpg The New York Times, Nov. 10, 1919]</ref><ref>[https://www.worldbooklearning.com/how-did-an-eclipse-help-make-albert-einstein-famous/ How did an eclipse help make Albert Einstein famous]</ref><ref>[https://blog.supplysideliberal.com/post/44934715350/how-albert-einstein-became-a-celebrity How Albert Einstein became a celebrity]</ref><ref>[https://www.sciencealert.com/general-relativity-experiment-confirms-accuracy-for-galaxies "The public's mind was blown by the results, effectively turning Albert Einstein into a household name and cementing the concept of general relativity into physics books."]</ref>

:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17th century "corpuscular" formulation or the 19th century "wave" formulation.

:It should be noted that pre-relativistic (Newtonian) physics may also predict a bending, of half the observed value, depending on whether one uses the 17th century "corpuscular" formulation or the 19th century "wave" formulation.

:Relying on circular assumptions, relativists assert that subsequent eclipses and the observations of quasar 3C273 confirm predictions of the theory, but no [[Nobel Prize]] has been awarded for this apparently due to the lack of rigorous science behind the claims.

:Relying on the usual assumptions (Newtonian mechanics, Galilean relativity, conservation of energy and momentum, the universality of the speed of light (that is, special relativity), the Equivalence Principle, and the geodesic equation in empty space (that is, general relativity), and the proper calibration of the instruments, observations of later eclipses, and the observations of quasar 3C273, confirm predictions of the theory.

 

:No [[Nobel Prize]] was was awarded for this.  A few years later Einstein won the Nobel Prize for the (unrelated) [[Photoelectric effect]].

*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury.  There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun.  These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century.  This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.

*The second "classical" test of general relativity was the advance of the perihelion of the orbit of Mercury.  There are many complex effects contributing to this, including gravitational perturbations from other planets and the effect of the oblateness of the Sun.  These are hard to calculate accurately, but, by 1900 it was known quite accurately that there was an "anomalous" precession, that is, a precession beyond all other known effects, of 43 arc seconds per century.  This is a very tiny effect, but astronomical measurements were sufficiently accurate by that time to show it clearly.

:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light.  A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref>  The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.

:Increasingly precise measurements of the precession demonstrate that it conflicts with General Relativity, despite claims of relativists for decades that it predicted the precession accurately in the amount of <math>3{}v^2/c^2</math> revolutions per planet's "year", where <math>v</math> is the planet's average orbital speed.<ref>That is a simple approximation, designed to relate the precession to the planet's speed relative to the speed of light.  A more accurate approximation is <math>\frac{3GM}{c^2 a(1-e^2)}</math>, where a is the semi-major axis and e is the eccentricity.</ref>  The conflict is greater than the margin of error, and many relativists avoid the discrepancy rather than address it.