Quote from: Space Flow
I would have appreciated a view on this paper but alas it was obviously not to be.I had a read of the paper, spread over 3 days...
The first thing to say is that I have never done a course on tensors, so I can't comment on the mathematics.
The second thing to ask is "What peer-reviewed physics journal did it appear in?". While I can't comment on the maths, the idea of a peer-reviewed physics journal is that they will find some experts who do understand it, to check it for me. (The http://philsci-archive.pitt.edu/ homepage describes it as a self-publishing site for papers on the philosophy of science).
As a layman, I think the crux of the article is this:
Quote from: Patrick M. Dürr
Slicing up such an approximation of the full metric into conservative and dissipative parts allows one to translate the resulting phenomena into a familiar Newtonian framework; the (heuristic or didactic) utility of such a translation, though, comes at the price of fundamentality.He says that dividing Einstein's gravity into a static (Newtonian) component, plus an oscillating/radiating gravitational wave component is valid, but it is arbitrary, unnecessary and he doesn't like it.
we restrict our discussion to interpreting the binary systems, modelled as point particlesThe modeling of the recent gravitational wave detection was not restricted to point particles. The transition from the inspiral phase to the ringdown phase involves the touching event horizons of the black holes, as extended objects.
Black holes won't experience the non-linear dissipation effects that could affect the orbit of neutron stars, like tidal bulges, tidal dissipation, tidal locking and tidal heating.
the onset of a scalar GW mode (propagating frequency dependently, subluminally and longitudinally)The author expects that if a gravitational wave existed, it would propagate:
- in a frequency-dependent manner: ie space would be a dispersive medium for gravitational waves. However, the chirp observed last September spanned almost an order of magnitude in frequency (50Hz to 400Hz), and arrived within a millisecond after an estimated billion years of travel. That appears to me that space is not a dispersive medium.
- at less than the speed of light: The 6ms delay between the two sites imply that it was traveling fairly close to c. The limits deduced for the mass of the graviton suggest that it was traveling extremely close to c.
- Longitudinally: the researchers analysed the phase differences between the two detectors, in an attempt to localize the source. They used the conventional model of gravitational wave propagation, but I expect they would have noticed some anomalies if it had been a longitudinal wave instead.
If energy is not conserved quite generally, there is no need to make up a story about where it has gone when a system loses it.The author is willing to make some significant changes to conventional physics (eg discarding conservation of energy) in order to justify his ignoring the possibility of gravitational waves.
I'm not sure I'm ready to "throw the baby out with the bathwater".
The following users thanked this post: Space Flow