GR is thriving despite newest guru Ferreira.
How curious that Pedro Ferreira views General Relativity (GR) as unchanged since the Einstein-Hilbert field equation of 1915 (New Scientist, 9 Oct. 2010, Relativity goes large). Einstein’s prediction of gravitational radiation (quadrupole formula) in 1919 and its validation by data from the double pulsar system in the 1970s were important advances in most physicists’ eyes.
The quadrupole formula depended on taking the far field as Newtonian, which removed ambiguity and showed that GR needs a supplementary relation. The orbital decay of the closely orbiting pulsars showed that energy-carrying gravitational waves are real, which had been doubted by many, including Einstein.
This Nobel-prize winning discovery has given confidence in the re-formulations of GR by Weinberg (1972), Logunov (1989) and Babak and Grishchuk (1990) that have a real energy-momentum tensor, unlike the pseudo-tensor of 1915.
Far from being unchanged, GR has been transformed into a coherent field description of gravitation, which Einstein sought in 1914 but never found because he took ‘gravity equates to bending of space-time’ too far. Let’s not deny the advance in understanding that gravitational waves are pulses of energy travelling through space, analogous to electromagnetic waves.
[New Scientist declined to publish this letter, submitted 23 Oct. 2010; cannot handle technical challenges to their chosen physics gurus]