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

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Tom said:
Light simply does not behave that way.




Light is not sound, and sound is not a good analogy for the behavior of
light. <shrug>
Click to expand...

Perhaps his neurons operate at the speed of sound, making it a good
analogy to *him* ;)
 
Phil said:
Perhaps his neurons operate at the speed of sound, making it a good
analogy to *him* ;)
Click to expand...

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 :-)
 
As can be seen "Phineas T Puddleduck" does not have the intelligence,
and knowledge of calculus and physics to describe how one can design an
energy "transducer",
Click to expand...

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]
 
Tom said:
They put a bird in orbit with an oscillator, noted how much various
factors like gravity affected the oscillators, and then they adjusted
the frequency dividers to get the outputs in sync.
Click to expand...

In other words, you are saying the pre-built [frequency] correction was in
fact actually derived from the environment experimentally, and not
mathematically pre-computed? [Just like the daily corrections are
experimentally computed, and not mathematically?]

Is there a source for this information?
Click to expand...

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 said:
I'd say pedantically (2), mostly because satellites do not understand
theory. :-) However, it's quite clear from the below that the builders of
the satellite were very cognizant of the correction, and included it so
that the satellite will function properly while in orbit.
Click to expand...

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 said:
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.
Click to expand...

Considering the equations that give the actual corrections predate the
GPS, I would say that this argument is pretty futile.
 
Bhanwara said:
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.
Click to expand...

http://math.ucr.edu/home/baez/RelWWW/wrong.html#gps

http://hermes.aei.mpg.de/2003/1/article.xhtml
 
Phineas said:
Considering the equations that give the actual corrections predate the
GPS, I would say that this argument is pretty futile.
Click to expand...

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 said:
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?
Click to expand...

The second one is a paper by Ashby all about the mathematical framework
of GPS. What browser are you using that cannot open xHtml?
 
**** said:
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?
Click to expand...

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!
 
Phil said:
I made no underlying assumptions. It was a joke. This thread is so far
off topic for sci.geo.satellite-nav (where I read it) that I would not
grace it with a serious response.
Click to expand...

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 said:
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.
Click to expand...

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.
 
<120620061517023902%[email protected]_NOSPAM>, Phineas T
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.
Click to expand...

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.
 

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