Einstein's Relativity and Everyday Life -- Clifford M. Will

Discussion in 'General GPS Discussion' started by Sam Wormley, Jun 5, 2006.

  1. Sam Wormley

    Phil Wheeler Guest

    Perhaps his neurons operate at the speed of sound, making it a good
    analogy to *him* ;)
     
    Phil Wheeler, Jun 12, 2006
  2. Sam Wormley

    Bhanwara Guest

    Phew! That's quite a compliment, though I am sure you
    didn't mean to make it a compliment.

    Contrary to your underlying assumption, neural signals
    do NOT propagate at the speed of light, the typical
    speed is in tens of meters per second. (There is
    a lot of stuff involved beyond just electrical
    transmission, don't ask.)

    Speed of sound in air is around 340 meters per second.

    I am very fast, but not quite that fast! But you may
    have a point in that this is a good analogy to *me*
    because my neural speed is closer to the speed of
    sound than my opponents', thus I understand
    the issues much better and much faster :)
     
    Bhanwara, Jun 12, 2006
  3. One can construe a solar collector as one-half of an energy transducer
    (the other half is the Sun, a gigantic fusion power plant).

    One can also construe a radiotelescope in a similar fashion. The
    energies, of course, are far smaller, but an antenna can be construed as
    one half of a gigantic open-space transformer, methinks.

    Even the eye is a transducer, if one wants to go that far; the energy of
    the light beam wiggles chemicals therein, causing nerves to fire and the
    brain to get notified that something interesting is nearby. (Most of the
    light reaching our eyes is from passive reflection, with one relatively
    interesting exception: the glowing of a monitor screen.)

    The other half is more complicated but one suggestion making the rounds on
    occasion is the boosting into orbit of gigantic solar collector units of
    some sort which convert the Sun's energy into microwaves, then beam these
    microwaves to ground-based collectors. Since these space-borne collectors
    would have to coexist with a lot of other satellites in an already crowded
    geosynchronous band or orbit, I for one am not all that hopeful regarding
    success of this particular notion. Plus, there is a suggestion that
    space-borne solar collectors will degrade because of the solar wind -- a
    reasonable suggestion, as far as I know, especially since rad-hard
    electronics are an attempt to combat the solar wind and extrasolar cosmic
    rays.

    Now, did you want something a little more specific, such as equations,
    drafting sheets, and parts lists? Or what?

    [rest snipped]

    [followups to sci.physics.relativity exclusively]
     
    The Ghost In The Machine, Jun 12, 2006
  4. NST-2 was built with a flip-switch of some sort. The flip-switch was used
    to switch between 10.24 MHz, and 10.239999995428 MHz or some such.
    Presumably this was in addition to other clock-steering logic, which for
    some reason I can't seem to get a description of the range thereof.
    (Note: 10.239999995428 MHz = 10.24 MHz - 0.00457 Hz. It's not a big
    correction but it does add up; various other things will affect the
    satellite clock such as gravitational anomalies from oil fields and other
    planets. These are extremely minute compared to this one.)

    The rest of the constellation was built and launched with this correction
    factored in.

    I don't know if there was an NST-1 but GR does darned well in predicting
    the correction. Other theories might do equally well, of course. I've
    not done the computation myself, though; I'm not competent in tensors.
     
    The Ghost In The Machine, Jun 12, 2006
  5. Sam Wormley

    Bhanwara Guest

    Not quite -- apparently it took the actual builders
    over eight years to find and build the actual
    corrections into the GPS.

    While there are many claims that SR and/or GR
    predicted the corrections, and certainly there
    are papers that postdict the corrections very well,
    an actual reference to a published paper that
    predicted the correction accurately before it
    was known, and that was published before
    any of the experimental data was available, would
    be interesting.
     
    Bhanwara, Jun 12, 2006
  6. Considering the equations that give the actual corrections predate the
    GPS, I would say that this argument is pretty futile.
     
    Phineas T Puddleduck, Jun 12, 2006
  7. http://math.ucr.edu/home/baez/RelWWW/wrong.html#gps

    http://hermes.aei.mpg.de/2003/1/article.xhtml
     
    Phineas T Puddleduck, Jun 12, 2006
  8. Sam Wormley

    Bhanwara Guest

    I was just requesting a reference. The equations and
    there interpretations are very malleable, and the
    said malleability does predate GPS by a lot, but
    can someone point out a reference to a paper that
    was published and that accurately predicted the
    correction before it was learned experimentally?
     
    Bhanwara, Jun 12, 2006
  9. Sam Wormley

    Bhanwara Guest

    The first one is just a general diatribe between some
    personalities, and my browser wants to save
    the second one instead of opening it.

    If these somehow contain a reference to a prediction that was
    published before the corrections were known experimentally,
    and that accurately predicted the correction, could you please post
    the actual reference?
     
    Bhanwara, Jun 12, 2006
  10. http://www.rand.org/pubs/monograph_reports/MR614/MR614.appb.pdf

    Is a historical background to GPS.
     
    Phineas T Puddleduck, Jun 12, 2006
  11. The second one is a paper by Ashby all about the mathematical framework
    of GPS. What browser are you using that cannot open xHtml?
     
    Phineas T Puddleduck, Jun 12, 2006
  12. Phineas T Puddleduck, Jun 12, 2006
  13. Sam Wormley

    dda1 Guest

    Here motherfucker:

    http://www.phys.lsu.edu/mog/mog9/node9.html

    and here old ****:

    http://hermes.aei.mpg.de/2003/1/article.xhtml

    If you continue your daily dose of shit eating you will grow dumb and
    blind. Oh wait, you are already dumb!
     
    dda1, Jun 12, 2006
  14. Phineas T Puddleduck, Jun 12, 2006
  15. Sam Wormley

    Sam Wormley Guest

    Sam Wormley, Jun 12, 2006
  16. Sam Wormley

    Bhanwara Guest

    I did take it as a joke! And a witty one at that.

    And the witticism was much appreciated. It was
    refreshing, given some posters in the relativity ngs
    have a habit of degenerating into raw rudeness (it
    was putting me into a foul mood until I realized
    it was just a couple of posters. Once I stopped
    reading those posters, I noticed the other posters
    have mostly responded like educated people.)

    But sci.geo.satellite-nav surely is a relevant
    ng for discussing GPS?
     
    Bhanwara, Jun 12, 2006
  17. No problem Sam..

    I've also found http://darwin.nap.edu/books/NI000187/html which isn't
    exactly deep, but is free to read online and a good springboard to
    further research!
     
    Phineas T Puddleduck, Jun 12, 2006
  18. Sam Wormley

    Bhanwara Guest

    Thanks. It says the publication acceptance
    date is 2003. But in reading through the list of
    references, I couldn't tell if there was an early
    one that did the original prediction before the
    data was known.
     
    Bhanwara, Jun 12, 2006
  19. Considering a lot of the design was by the US military, perhaps some
    emails asking for papers.

    Not being rude, but I found all the above through simple googling. A
    quick couple of emails should help.
     
    Phineas T Puddleduck, Jun 12, 2006
  20. <120620061517023902%_NOSPAM>, Phineas T
    Simple explanation here. As the US military designed and built the
    system, I would find it difficult to see whether anyone would have
    academically done all the calculations before hand. The research which
    lead to it was probably internal to the military, and any academic
    research would have come after.

    Still doesn't invalidate the fact that all the equations were there
    well before its launch, it just means you may need to do some emailling
    to ask.
     
    Phineas T Puddleduck, Jun 12, 2006
Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Similar Threads
There are no similar threads yet.
Loading...