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Theory of relativity (view source)
Revision as of 18:14, September 7, 2018
, 18:14, September 7, 2018→Experimental and Observational Evidence Confirming Relativity: Explain what we mean by "validate". I'll do the assumptions next.
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.
Because the effects of relativity are so tiny, scientists have been devising sophisticated and sensitive tests ever since the theory was formulated in 1905.
It is important to be aware that it is fairly rare for an experiment to '''prove''' a theory. In general, experiments can only '''refute''' a theory. They can also '''be consistent with''' a theory. When enough experiments, especially experiments that investigate a wide variety of phenomena, are shown to be consistent with a theory, it lends credence to that theory. When no other plausible theory can explain those observations, we can say that they '''validate''' the theory. The Mercury observations are just one phenomenon. By themselves they couldn't validate or prove GR. And there was at one time another competing theory—the Newcomb-Hall exponent-fudging theory. That one didn't hold up for things other than Mercury. No other theory has come up explaining the phenomenon; GR has withstood the test of time. That goes a long way toward validating GR. There are many other observations and experiments, covering a wide variety of phenomena, described below—bending of light, gravitational time dilation, gravitational waves, geodetic precession, Shapiro effect, etc. It is these widely disparate observations, and the lack of any alternative theories explaining any of them, that lead people to say that GR is "experimentally validated".
The most famous experiment, and the one that is commonly cited in textbooks as the experiment that established the case for relativity,<ref>Though relativity did not actually originate from this experiment</ref> was the [[Michelson-Morley experiment]]. This showed that all observers will obtain the same measured value for the speed of light (3x10<sup>8</sup> meters per second) no matter what their state of motion. This is the first of the two fundamental principles:
The most famous experiment, and the one that is commonly cited in textbooks as the experiment that established the case for relativity,<ref>Though relativity did not actually originate from this experiment</ref> was the [[Michelson-Morley experiment]]. This showed that all observers will obtain the same measured value for the speed of light (3x10<sup>8</sup> meters per second) no matter what their state of motion. This is the first of the two fundamental principles: