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From: John Jones on 7 May 2010 17:29 glird wrote: > > This topic really should be discussed on the relativity group. - > fd > > Your message has been rejected because it is off topic of the > moderated group sci.physics.foundations. > > On Mar 20, 3:19 am, Tom Roberts wrote: > > glird wrote: > > > > > As of now, no gravitational waves have ever been detected. > > > Why, then, are most physicists sure they exist? > > > > This is not true. Hulse and Taylor received a Nobel Prize for the > detection of the emission of gravitational waves by a distant binary > pulsar. That is an indirect detection, and lends plausibility to their > existence, and implies that GR is a good model of them. > > > Although "an indirect 'detection'" did lend "plausibility to the > existence" of g-waves, my statement holds good. > > TR: We aren't "sure" they exist, we just think it is quite likely > and > merits the effort [= $$$$$] required to detect them directly. > > If, as you implied, the emission of gravitational waves has been > detected, then why aren't our physicists sure they exist? > > g: < As Lorentz pointed out, because the arms of an interferometer > shrink by Q, q, q in the X, Y, Z directions -- where Q = q^2 = c^2 - > v^2 and X is the direction of motion, a beam of light will take the > same amount of time to round-trip the arms even though the arms are > different lengths than each other AND the speed of light is similarly > different relative to each such leg. > Tom Roberts will disagree, of course. He believes that the length > contractions don't physically happen, but are due to rotations of > the X axis of a moving system, as Minkowski assumed. > > > TR: It's not just me, it's everybody who understand SR. That > includes tens of thousands of physicists. > > If you were right, then (as proved below) that EXcludes Albert > Einstein! > > g: Even so, we have a right to assume that the axes of any moving > system are and remain parallel to each other. > > TR: No, you have no such "right" -- you must follow the structure of > the model. > > You can follow Minkowski's model, but I will follow E's SR model. > E wrote, > "Now to the origin of one of the two systems (k) let a constant > velocity v be imparted in the direction of the increasing x of the > other stationary system (K), and let this velocity be communicated > to the axes of the co-ordinates, the relevant measuring-rod, and > the clocks. To any time of the stationary system K there then will > correspond a definite position of the axes of the moving system, > and ... we are entitled to assume that the motion of k may be such > that the axes of the moving system are [and remain] ... parallel to > the axes of the stationary system." > > TR: In SR, the rotation is in a space-time plane -- in 3-space they > remain parallel (for the usual simple situation of a moving ruler > aligned along the x and x' axes moving inertially along those same > axes).> > > In fantasy land there might be an xyz;t plane. In reality, a plane > is an imaginary mathematical construction with TWO dimensions, not > three or four. In normal space, as in Einstein's world -- in which > time was NOT a dimension -- all three spatial axes are and remain > parallel despite Minkowski's mythical delusions. > > glird |