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andrew s

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Blog Comments posted by andrew s

  1. @Gina, I have been watching your heroic efforts but do wonder if the physical properties of your material is suitable for a clock escapement. I don't know what they are but I suspect they are quite different from traditional  material (brass ?).

    I would worry about Youngs modulus , creep, coefficient  of restitution and coefficient of friction for a start!

    Nevertheless I hope you succeed. 

    Regards Andrew 

  2. Nice job looking forward to seeing the results.

    Is the grating blazed? If it is it would be worth angling the camera to center the first order. 

    This is what I have done on my fiber fed low resolution spectrograph. It has extra lenses as the grating is in a collimated beam it also does not need to be attached to the telescope.

    Regards Andrew

     

    Very low res.jpg

  3. "Under certain conditions an observer in a stationary or moving reference frame may not have to apply the principle of addition of velocities from the Galilean or Lorentz transformation equations to the propagating sound wave. "

    Assuming you mean inertial reference frames:

        What conditions ?

        Stationary or moving with respect to what?

    The equivalence of physical laws in inertial frames has been verified by countless experiments do you have an experimental result that contradicts it? 

    Regards Andrew

  4. It is certainly true that light in a medium does not travel at the vacuum speed c and that the relative motion of the medium and the observer effects this. However, I don't think this invalidates special relativity and the use of flat Minkowski space-time. 

    General relativity is much more complex but even in GR nothing can out run light. (It is complex as in general you can't simply compare or add velocities of widely spaced points in strongly curved space-time.)

    On a cosmological scale simple ideas like distance and time between events is difficult to get to grips with due to the metric expansion of space-time. The best that can normally be done is to consider observers co-moving with the metric expansion (i.e. they see the CMB as homogeneous and isotropic - give or take the minute fluctuations) as a time base and ask how they would measure the distances when their CMB clocks align. Other than that you get (as in special relativity) observer dependent answers.

    Having said that SR and GR are the best tested theories we have in their domains and I see no reason to give them up.

    Regards Andrew

     

    • Like 1
  5. 39 minutes ago, acey said:

    It's empirically verified that the speed of light in a vacuum is a universal constant, independent of reference frame. There is no analogous principle for sound waves. Hence one cannot attempt to reframe special relativity using sound, or any other form of energy transfer apart from radiation.

    Absolutely right. In addition the speed of sound varies even within an inertial frame, it changes literally with the weather.

    Regards Andrew

    • Like 2
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