Changes

Unlike special relativity, predictions of general relativity turn out to be obscure and difficult to test.  The two most famous predictions in the early days were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.  Several other phenomena have arisen more recently.

Unlike special relativity, predictions of general relativity turn out to be obscure and difficult to test.  The two most famous predictions in the early days were the bending of light in a gravitational field and the precession of the perihelia of orbiting planets.  Several other phenomena have arisen more recently.

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>

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 observed result was about 1.5 arc seconds. 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, depending on whether one uses the 17th century "corpuscular" formulation or the 19th century "wave" formulation.  The former would give a value of 0.875 arc seconds, while the latter would give a value of zero.

:Relying on the usual assumptions&mdash;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.

:Relying on the usual assumptions&mdash;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, which is that the bending is 1.75 arc seconds.

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

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