Whitehead's theory of gravitation
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In theoretical physics, Whitehead's theory of gravitation was an early competitor of Einstein's theory of general relativity. It was introduced by the distinguished mathematician and philosopher Alfred North Whitehead in 1922. It is now considered obsolete.
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[edit] Principle features of the theory
Whitehead's theory is said to feature a prior geometry. It has the curious feature that electromagnetic waves propagate along null geodesics of the physical spacetime (as defined by the metric determined from geometrical measurements and timing experiments), while gravitational waves propagate along null geodesics of a flat background represented by the metric tensor of Minkowski spacetime.
[edit] Tests of Whitehead's theory
Whitehead's theory makes the same predictions as general relativity regarding the four classical solar system tests (gravitational red shift, light bending, perihelion shift, Shapiro time delay), and was regarded as a viable competitor of general relativity for several decades. Eventually, Clifford M. Will noticed that the theory makes predictions concerning ordinary ocean tides on Earth which are in violent disagreement with observation, which immediately nullified this theory.[1]
In 1989, a new interpretation of Whitehead's theory was proposed that accorded with those observed tidal effects.[2] However, the new interpretation did not satisfy another observed effect, called the "Nordtvedt Effect."
[edit] Its philosophical significance
For the several decades in which Whitehead's theory was in principle a viable competitor to Einstein's General Relativity, the question may be asked: why was the theory not considered a true alternative? For clearly, if it had been, it would have been tested (and refuted) far sooner. As such, it demonstrates the interesting dynamic of the adoption or rejection of scientific theories: that the scientific community chooses theories not only according to their predictive powers, but also according to vague and mostly intuitive considerations of "elegance" and "plausibility".
[edit] Footnotes
- ^ Will, Clifford & Gibbons, Gary. "On the Multiple Deaths of Whitehead's Theory of Gravity", to be submitted to Studies In History And Philosophy Of Modern Physics (2006).
- ^ Hyman, Andrew. "A New Interpretation of Whitehead's Theory", 104B Il Nuovo Cimento 387 (1989).
[edit] See also
[edit] References
- Will, Clifford M. (1993). Was Einstein Right?: Putting General Relativity to the Test, 2nd ed.. Basic Books. ISBN 0-465-09086-9.
- Misner, Charles; Thorne, Kip S. & Wheeler, John Archibald (1973). Gravitation. San Francisco: W. H. Freeman. ISBN 0-7167-0344-0. discusses Whitehead's theory in various places.
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