GRAVITATIONAL WAVES---joke or swindle?
Updated: Apr 23, 2020
--to paraphrase Louis Essen's opinion of "relativity" which was a combination of Rutherford treating it as a joke and Soddy's view that it was a swindle.
On the 14th of September 2015, the LIGO team reported the coalescence of two black holes (BH) of 36 and 29 solar-masses into a final BH of 62 solar-mass with 3 solar rest energy radiated as gravitational waves (GW). According to the letter in Phys. Rev. Lett. [ 116 061102 (2016)] "[t]hese observations demonstrate the existence of binary stellar-mass systems. This is the first direct observation of a black hole merger."....And all this from an extremely faint signal that lasted for 0.2 seconds!
However, all this was foreseen long ago, as reported in Kip Thorne's book Black Holes and Time Warps: Einstein's Outrageous Legacy that was published in 1994. Describing an imaginary space mission, Thorne writes" at the time you left Earth, there was a binary stellar star system composed of two 30-solar-mass stars orbiting each other." These stars imploded to form two 24-solar mass holes with 6 solar-mass ejected during implosion. The two new 24-solar mass holes should "now be circling around each other as a black-hole binary, and as they circle, they should emit ripples of tidal force (ripples of "space-time curvature") called gravitational waves." These gravitational waves should push back on the gun that fires it, and this gravitational wave recoil should drive the holes into a slow inexorable inward spiral.
A pictorial description was even provided by LIGO
What has changed since then. Later on in the book Thorne realizes that "Since spacetime curvature is the same as gravity, these ripples of curvature are actually waves of gravity, or gravitational waves. Einstein's general theory of relativity predicts, unequivocally, that such gravitational waves must be produced whenever two black holes orbit each other--and also whenever two stars orbit each other." Thus, there is no reason why the initial pair of orbiting black holes should not have already emitted gravitational waves. And the spacetime curvature is there even when there is no mass!
Continuing, Thorne writes that "[a]s they depart for outer space, the gravitational waves push back on the holes in much the same way as a bullet kicks back on the gun that fires it. The waves' push drives the holes closer together and up to higher speeds; that is, it makes them slowly spiral inward toward each other. The inspiraling gradually releases gravitational energy, with half of the released energy going into the waves and the other half into increasing the holes' orbital speeds."
The original size of the holes are surprisingly (?) close to what was supposedly observed by the LIGO team. The radiated energy was half the predicted amount, probably taking into account the statement that "half of the released energy going into the waves...." But what about the energy that was supposedly released upon the initial ejection of gravitational waves that provided the mechanism of kick-back that sends the binary pair into an orbital whirlwind?
And finally, when do tidal forces create ripples in spacetime? The entire notion of a force is foreign to Einstein's theory of general relativity so ascribing forces that create effects is equally foreign to the theory. So the mechanism of a back-reaction was deleted from the scenario.