Re: I am Trying To Learn Relativity

On Wed, 08 Jul 2009 20:15:25 -0500, Tom Roberts <tjroberts137@xxxxxxxxxxxxx>
wrote:

Mike wrote:
On Jul 7, 10:18 pm, Tom Roberts <tjroberts...@xxxxxxxxxxxxx> wrote:
2+2=5 wrote:


Here's what that means: let each observer be moving inertially and have
a co-moving array of assistants that each has a clock synchronized to
the observer's (synchronized in the inertial frame of observer and
assistants). So when the flash reaches each assistant they write down
the time they saw the flash, and send it to the observer. The observer
then correlates the recorded time of flash and position of assistant,
and concludes the flash traveled outward with speed c in all directions
to all assistants. BOTH observers perform this whole rigmarole, and BOTH
get the same answer: c. Even though they are moving differently and were
both right next to the source when it flashed.

No way.

Yes way. This is how SR describes this.

It is how an idiot would describe it.
Obviously, by synching clocks with light, SR effectively uses the flash to
ensure that all the clocks read the same when the flash arrives.
What kind of logic is this?

The one way speed of light constance is a requirement fro
relative simultaneity. it is not a result of such convention.

These things are all related, and one cannot unambiguously say which is
"result" and which is "choice" (or "convention" or "postulate").

In SR, simultaneity is relative, and light travels with one-way speed c
wrt any inertial frame. Both are aspects of the model, and neither is
really a "result" of the other.


You are confusing conventions with models of physical reality.

No. SR is a model of physical reality. It applies even if one chooses to
synchronize clocks differently. Of course one must include the
synchronization method used when analyzing experiments. The coordinate
clocks of SR's inertial frames are indeed synchronized using light (or
equivalent), but you are free to synchronize the real clocks of your
experiment any way you like; you can still apply SR.

Clocks can be presynched whilst together then moved into any required position.
If their stability is known and it is good enough for whatever experiment they
wil perform, then there is no problem. They may be assumed to be in synch.

simultaneity and whether it is a matter of convention or
not, does not depend on speed.

No. But the set of events that are simultaneous in one inertial frame
are not simultaneous in another inertial frame moving with respect to
the first. Here "event" means a point in the 4-d spacetime denoted by
specific values of a set of inertial coordinates {x,y,z,t}.

Wrong. I showed you weeks ago how and why simultaneity is absolute. If both
observers use an array of presynched clocks to measure the event times, they
will both agree on simultaneity.
This is terribly simple really.

SR is perfectly inconsistent [...] Nice mathematical theory but defies not
only common sense but sense in general.

Not true. The geometry of SR has been proven to be as self-consistent as
is Euclidean geometry, and as is real analysis. As I said before your
common sense is not a valid evaluation, and your "sense in general" is
the same thing.


The fact that experiments confirm SR is because when it is projected
in a 3-D world, the inconsistencies cannot be measured and the
prediction sare indistinguishable from equivalent theories that do not
require the constancy of the speed of light. So those experiments
confirm also those other theories.

There is indeed a set of theories that are experimentally
indistinguishable from SR. But they ALL disagree with your personal
"common sense".

SR is an accurate and valid model of the world we inhabit, regardless of
what your "common sense" says -- your "common sense" is IRRELEVANT.

As I said before, YOU have no relevant experience from which
to obtain "common sense" in the regime where SR is important.
Those of us who do have such experience, at particle
accelerators and experiments, know SR is valid.

There is an alternative explanation for any experiment that supposedly supports
SR.


Henry Wilson...www.users.bigpond.com/hewn/index.htm

.........putting Physics back into Phairyland...
.

Relevant Pages

  • Re: I am Trying To Learn Relativity
    ... a co-moving array of assistants that each has a clock synchronized to ... In SR, simultaneity is relative, and light travels with one-way speed c wrt any inertial frame. ... It applies even if one chooses to synchronize clocks differently. ... The coordinate clocks of SR's inertial frames are indeed synchronized using light, but you are free to synchronize the real clocks of your experiment any way you like; ...
    (sci.physics.relativity)
  • Re: I am Trying To Learn Relativity
    ... let each observer be moving inertially and have ... a co-moving array of assistants that each has a clock synchronized to ... Obviously, by synching clocks with light, SR effectively uses the flash to ... wrt any inertial frame. ...
    (sci.physics.relativity)
  • Re: I am Trying To Learn Relativity
    ... synchronize clocks differently. ... but you are free to synchronize the real clocks of your ... opposite directions) in an inertial frame. ... at our disposal on earth being not-quite-inertial. ...
    (sci.physics.relativity)
  • Re: Are *observed* SR effects real?
    ... the motion of the observer does ... So if we use a light signal between the two clocks, ... in the frame in which they are at rest. ... clocks at rest relative to that frame, and we want to synchronize two ...
    (sci.physics.relativity)
  • Re: Are *observed* SR effects real?
    ... So if we use a light signal between the two clocks, ... in the frame in which they are at rest. ... clocks at rest relative to that frame, and we want to synchronize two ... and the observer in A says the other observer did NOT ...
    (sci.physics.relativity)