On Tue, May 24, 2016 at 04:20:02PM +0000, Bruce Johnson wrote: > > > On May 23, 2016, at 7:31 PM, Tim <xxxxxx@little-possums.net> wrote: > > > > Not at all. Gravitational waves corresponding to highly nonlinear > > changes in the structure of spacetime (e.g. opening a connection from > > jumpspace) should be expected to be astronomically greater in > > magnitude than everything else. > > Why? I may be visualizing this completely wrong, but the analogy I’m > thinking is a rock placed (not thrown) halfway into a pond. That > sets up a ripple as displaced water pushes out. Spacetime behaves very differently from water. For example, an object moving at constant velocity does not radiate gravitational waves at all. An accelerating one does, but in most cases *extremely* weakly, with radiated power something like G (m v a)^2 / c^5. So for Traveller vehicles, typically 10^-18 watts or less. The scale of gravitational waves from jump emergence depends upon your assumptions. If you treat it like formation, transit, and collapse of a small wormhole endpoint over time t, then the radiated energy from a diameter d would be on the order of c^3 d^2 / (G t^2). So if jump emergence takes on the order of a few seconds, the gravitational radiation during that time would be typically on the order of 10^36 watts. Yes, this is a ridiculously large power, because folding, spindling, and mutilating spacetime involves ridiculously large energies. If you merely treat it as the appearance of mass-energy into an existing spacetime, then the changing monopole moment (which normally isn't possible!) yields power about G m^2 c / d^2, where d is the diameter of the body. For Traveller starships, that's going to be on the order of 10^10 watts. LIGO might detect it if a ship emerged at Earth's 100 D, but probably not at interplanetary ranges. It would be quite reasonable for more advanced detectors to do so, however. Obviously the first assumption for jumpspace emergence yields very much greater gravitational radiation than the second, but even the second one is 10^28 times the power of ordinary waves from acceleration. The ratio is comparable to the that between a candle and the Sun, and enormously greater than the ratio between a pin dropping and a magnitude 9 earthquake. To say "if you can detect one then you can detect the other" is an error of scale far beyond the normal range of such errors. > Yeah, but if you have an interferometer with, say 100Km, or 10,000km > arms? With TL12 or TL14 scale weapons-grade lasers? Obviously I don't know what higher TLs will bring, but I'd be quite surprised if a few extra TLs increased the sensitivity by a factor of a quadrillion. All I was saying is that the two cases of gravitational radiation that you were calling similar are actually radically different, and obviously the subsequent argument for universal tracking of non-jump movement does not follow. - Tim
