'HannesAlfven' on relativity, responding to Rob:
A classic example is Einstein’s theory of gravity, general relativity. The big idea was that matter and energy curved spacetime, and that this curved spacetime was the cause of all the effects we attribute to gravitational force.But it didn’t just explain all of the things that the old theory, Newton’s gravity, explained. It also predicted an anomaly in Mercury’s orbit, which had been observed but was hitherto unexplained. But additionally, it also made a brand new prediction: that near very massive objects, starlight would appear to bend!
This is unfortunately the textbook story of what happened. The more nuanced historical story which philosophers debate involves an additional photographic plate which was in conflict with Einstein's prediction.Does 'HannesAlfven' think this eclipse in 1919 was the ONLY time in history this experiment could be done?
He ignores the fact that while some additional photographic plates taken in 1919 did not agree with Einstein's prediction, the measurements being attempted were at the limit of 1919 technology and it's easy to make mistakes, as any competent experimentalist knows. 'HannesAlfven' blatantly ignores the fact that these observations have been repeated by others in the over 90 years since the original observation with better instruments and higher precision:
- The relativity shift at the 1952 February 25 eclipse of the Sun.
- The Measurement of the Light Deflection from Jupiter: Experimental Results
- Testing relativity from the 1919 eclipse—a question of bias
- Progress in Measurements of the Gravitational Bending of Radio Waves Using the VLBA
- A test of general relativity using radio links with the Cassini spacecraft
- Hipparcos tested the bending to one part in 1000 (Relativity and the 1919 eclipse).
- Wikipedia: Tests of General Relativity: Gravitational Lensing
'HannesAlfven' also ignores the reason of WHY scientists do this type of repetitive testing of existing theories as experimental precision improves. If discrepancies are found with improved precision, it could be the indicator of the next theory more precise than relativity - just as general relativity first appeared as a descrepancy in the predictions of Newtonian gravity (Wikipedia).