Ken S. Tucker wrote:
sal wrote:
Here's a (relatively) simple view of the Sagnac effect:

http://www.physicsinsights.org/sagnac_1.html

I tried to cut through the fog of algebra that often obscures web pages
that talk about the Sagnac effect: The math on the page includes nothing
harder than a Lorentz transform, and no messy integrals. In fact, the
Sagnac effect is pretty simple if one avoids getting bogged down in the
details of the rotation.

Unlike Eugene and Wittke I don't claim this page contains earth-shattering
new physics, nor that it displays such blinding brilliance on my part that
you should wear sunglasses while reading it, but none the less some might
find it worthwhile. If you don't understand the Sagnac effect, take a
look at it; maybe my point of view will help.

And the effect certainly seems to put paid to ballistic theory, as Paul
Andersen has been saying for ages and ages (though I never quite
understood what he meant until I worked it out for myself).

Comments welcome, of course!

http://www.paineless.id.au/missiles/Sprint.html

Look down and find laser gyro's for Hibrex,
Rocket scientists don't use relativity, it's
a straightforward classical thingy.
Ken



Sal and all...

Sal is one my favorite posters no flame intended.

I used (ref'd) the developement of the laser-gyro for the
Hibex/Sprint missiles for some practical background.

The sublte rates of rotation of the missiles do (IMO)
measure a v/c ratio - using Sagnet - but the (v/c)^2
ratio is a tiny correction.

For example if the classical Sagnet gives

v/c = 10^-10 then (v/c)^2 = 10^-20,

(c in vacuum), thats 1 part in 10^10 that's a
relativistic correction, rocket science wouldn't
use that to often.

The v/c is of the order of Doppler or Aberration
effects, and those are usually regarded as classical,
i.e. SR is not required to 1st order as I show above.

As Sal invited comments, I think, a classical
explanation is 1 order , followed by the relativistic
corrections in 2 order.
Ken S. Tucker

PS: We can get ourselves into some good GR by
comparing relatively rotating CS's and the metrics.

"Ken S. Tucker" wrote in message
oups.com...
|

| As Sal invited comments, I think, a classical
| explanation is 1 order , followed by the relativistic
| corrections in 2 order.
| Ken S. Tucker

Totally agree, the presentation given is prejudiced.

Androcles

Androcles wrote:
"Ken S. Tucker" wrote in message
oups.com...
|

| As Sal invited comments, I think, a classical
| explanation is 1 order , followed by the relativistic
| corrections in 2 order.
| Ken S. Tucker

Totally agree, the presentation given is prejudiced.
Androcles

Well Sal's a bit smarter and has studied the problem,
but IMO leaning too hard into SR is a push in terms
of theoretics, since an examination of the classics
is the way to at least start.
Ken

"Ken S. Tucker" wrote in message
oups.com...
|
| Androcles wrote:
| "Ken S. Tucker" wrote in message
| oups.com...
| |
|
| | As Sal invited comments, I think, a classical
| | explanation is 1 order , followed by the relativistic
| | corrections in 2 order.
| | Ken S. Tucker
|
| Totally agree, the presentation given is prejudiced.
| Androcles
|
| Well Sal's a bit smarter and has studied the problem,
| but IMO leaning too hard into SR is a push in terms
| of theoretics, since an examination of the classics
| is the way to at least start.
| Ken

Like you, sal makes the error of transforming the stationary parameters
of tau(x,0,0,t) to the moving frame instead of transforming the moving
parameters tau(x',0,0,t).
x' = x-vt,
xi = x'/sqrt(1-v^2/c^2),
but in the moving frame v = 0, unless you think you can walk faster
than yourself.
The cuckoo transforms Einstein blames Lorentz for but wrote himself
are meaningless drivel.
Androcles

Androcles wrote:
"Ken S. Tucker" wrote in message
oups.com...
|
| Androcles wrote:
| "Ken S. Tucker" wrote in message
| oups.com...
| |
|
| | As Sal invited comments, I think, a classical
| | explanation is 1 order , followed by the relativistic
| | corrections in 2 order.
| | Ken S. Tucker
|
| Totally agree, the presentation given is prejudiced.
| Androcles
|
| Well Sal's a bit smarter and has studied the problem,
| but IMO leaning too hard into SR is a push in terms
| of theoretics, since an examination of the classics
| is the way to at least start.
| Ken

Like you, sal makes the error of transforming the stationary parameters
of tau(x,0,0,t) to the moving frame instead of transforming the moving
parameters tau(x',0,0,t).
x' = x-vt,
xi = x'/sqrt(1-v^2/c^2),
but in the moving frame v = 0, unless you think you can walk faster
than yourself.
The cuckoo transforms Einstein blames Lorentz for but wrote himself
are meaningless drivel.
Androcles

You cannot condemn an entire progran just for
a single slip-up!

"Ken S. Tucker" wrote in message
oups.com...
|
| Androcles wrote:
| "Ken S. Tucker" wrote in message
| oups.com...
| |
| | Androcles wrote:
| | "Ken S. Tucker" wrote in message
| | oups.com...
| | |
| |
| | | As Sal invited comments, I think, a classical
| | | explanation is 1 order , followed by the relativistic
| | | corrections in 2 order.
| | | Ken S. Tucker
| |
| | Totally agree, the presentation given is prejudiced.
| | Androcles
| |
| | Well Sal's a bit smarter and has studied the problem,
| | but IMO leaning too hard into SR is a push in terms
| | of theoretics, since an examination of the classics
| | is the way to at least start.
| | Ken
|
| Like you, sal makes the error of transforming the stationary
parameters
| of tau(x,0,0,t) to the moving frame instead of transforming the
moving
| parameters tau(x',0,0,t).
| x' = x-vt,
| xi = x'/sqrt(1-v^2/c^2),
| but in the moving frame v = 0, unless you think you can walk faster
| than yourself.
| The cuckoo transforms Einstein blames Lorentz for but wrote himself
| are meaningless drivel.
| Androcles
|
| You cannot condemn an entire progran just for
| a single slip-up!

Why not? I've done it to Henri Wilson and I can do it to Einstein.
Copernicus did it to Ptolemy, so there is precendent.

Androcles

Androcles wrote:
"Ken S. Tucker" wrote in message
oups.com...
|
| Androcles wrote:
| "Ken S. Tucker" wrote in message
| oups.com...
| |
| | Androcles wrote:
| | "Ken S. Tucker" wrote in message
| | oups.com...
| | |
| |
| | | As Sal invited comments, I think, a classical
| | | explanation is 1 order , followed by the relativistic
| | | corrections in 2 order.
| | | Ken S. Tucker
| |
| | Totally agree, the presentation given is prejudiced.
| | Androcles
| |
| | Well Sal's a bit smarter and has studied the problem,
| | but IMO leaning too hard into SR is a push in terms
| | of theoretics, since an examination of the classics
| | is the way to at least start.
| | Ken
|
| Like you, sal makes the error of transforming the stationary
parameters
| of tau(x,0,0,t) to the moving frame instead of transforming the
moving
| parameters tau(x',0,0,t).
| x' = x-vt,
| xi = x'/sqrt(1-v^2/c^2),
| but in the moving frame v = 0, unless you think you can walk faster
| than yourself.
| The cuckoo transforms Einstein blames Lorentz for but wrote himself
| are meaningless drivel.
| Androcles
|
| You cannot condemn an entire progran just for
| a single slip-up!

Why not? I've done it to Henri Wilson and I can do it to Einstein.
Copernicus did it to Ptolemy, so there is precendent.

Androcles

Sal ran a theoretical experiment, float a balloon
see where it goes...and he posted that question.
Ken

On Wed, 03 Aug 2005 08:03:49 -0700, Ken S. Tucker wrote:


Ken S. Tucker wrote:
sal wrote:
Here's a (relatively) simple view of the Sagnac effect:

http://www.physicsinsights.org/sagnac_1.html

[ ... ]


http://www.paineless.id.au/missiles/Sprint.html

Look down and find laser gyro's for Hibrex, Rocket scientists don't
use relativity, it's a straightforward classical thingy. Ken

Sal and all...

Sal is one my favorite posters no flame intended.

I used (ref'd) the developement of the laser-gyro for the Hibex/Sprint
missiles for some practical background.

And it's an extremely entertaining page. 400 gravities?? That's like
how fast you stop if you fall out of an airplane and land on cement.
But I didn't see that it had a lot to say about the classical or
otherwise nature of the Sagnac effect.


The subtle rates of rotation of the missiles do (IMO) measure a v/c
ratio - using Sagnac - but the (v/c)^2 ratio is a tiny correction.

For example if the classical Sagnet gives

v/c = 10^-10 then (v/c)^2 = 10^-20,

(c in vacuum), thats 1 part in 10^10 that's a relativistic
correction, rocket science wouldn't use that to often.

Yes, that's true ... but it's not what I was thinking of. I missed
the fact that one could predict it "classically" to first order.

I had forgotten completely about Fresnel/Fizeau and the notion of
"partial dragging" of the aether, which lets one predict the Sagnac
effect in glass using classical aether theory. (If I ever actually
knew about it to start with...) I was thinking in terms of either
ballistic theory, or aether theory with no dragging, or aether theory
with full dragging (which produces the same result as ballistic theory
in this case, of course). In the first and third cases you get no
Sagnac effect, in the second case you get the wrong amount (not sure
how far off it is -- for a high-index glass fiber where signal
velocity is k ~ c/2, it looks like it's first order in v, though: CofV
yields

u ~ k + v(1-k^2)

if rim speed is v unless I messed that up) but the second case is just
too weird an assumption to make, anyway.

Anyhow I've gotta rewrite parts of the page again; the effect is
indeed classically predictable so I shouldn't claim it isn't.


The v/c is of the order of Doppler or Aberration effects, and those
are usually regarded as classical, i.e. SR is not required to 1st
order as I show above.

Right -- but the sticky point is that you need to come up with some
explanation for why the velocity of light in a glass fiber is not C/N
relative to the fiber.


As Sal invited comments, I think, a classical explanation is 1
order, followed by the relativistic corrections in 2 order.
Ken S. Tucker

PS: We can get ourselves into some good GR by comparing relatively
rotating CS's and the metrics.


--
Nospam becomes physicsinsights to fix the email
I can be also contacted through http://www.physicsinsights.org

sal wrote:
On Wed, 03 Aug 2005 08:03:49 -0700, Ken S. Tucker wrote:


Ken S. Tucker wrote:
sal wrote:
Here's a (relatively) simple view of the Sagnac effect:

http://www.physicsinsights.org/sagnac_1.html

[ ... ]


http://www.paineless.id.au/missiles/Sprint.html

Look down and find laser gyro's for Hibrex, Rocket scientists don't
use relativity, it's a straightforward classical thingy. Ken

Sal and all...

Sal is one my favorite posters no flame intended.

I used (ref'd) the developement of the laser-gyro for the Hibex/Sprint
missiles for some practical background.

And it's an extremely entertaining page. 400 gravities?? That's like
how fast you stop if you fall out of an airplane and land on cement.
But I didn't see that it had a lot to say about the classical or
otherwise nature of the Sagnac effect.

Well at the bottom of the page, see HIBEX and the
rational to develope laser gyros to replace
mechanical gyros. I thought that was utlra coool...

The subtle rates of rotation of the missiles do (IMO) measure a v/c
ratio - using Sagnac - but the (v/c)^2 ratio is a tiny correction.

For example if the classical Sagnet gives

v/c = 10^-10 then (v/c)^2 = 10^-20,

(c in vacuum), thats 1 part in 10^10 that's a relativistic
correction, rocket science wouldn't use that to often.

Yes, that's true ... but it's not what I was thinking of. I missed
the fact that one could predict it "classically" to first order.

I had forgotten completely about Fresnel/Fizeau and the notion of
"partial dragging" of the aether, which lets one predict the Sagnac
effect in glass using classical aether theory. (If I ever actually
knew about it to start with...) I was thinking in terms of either
ballistic theory, or aether theory with no dragging, or aether theory
with full dragging (which produces the same result as ballistic theory
in this case, of course). In the first and third cases you get no
Sagnac effect, in the second case you get the wrong amount (not sure
how far off it is -- for a high-index glass fiber where signal
velocity is k ~ c/2, it looks like it's first order in v, though: CofV
yields

u ~ k + v(1-k^2)

if rim speed is v unless I messed that up) but the second case is just
too weird an assumption to make, anyway.

Beyond the 1 order the 2 order includes SR and GR.
If one examines Sagnet beyond classical 1 order
I think GR (relativity of rotating frames and
centifugals) becomes the prominent explanation.

We should expect GR accounts for 1,2...orders.

Anyhow I've gotta rewrite parts of the page again; the effect is
indeed classically predictable so I shouldn't claim it isn't.

I agree with most of the guys, you got a good
start. How many people even take the time to
try to explain something so complicated.

The v/c is of the order of Doppler or Aberration effects, and those
are usually regarded as classical, i.e. SR is not required to 1st
order as I show above.

Right -- but the sticky point is that you need to come up with some
explanation for why the velocity of light in a glass fiber is not C/N
relative to the fiber.

ok...

"Ken S. Tucker" wrote in message
oups.com...
|
| Androcles wrote:
| "Ken S. Tucker" wrote in message
| oups.com...
| |
| | Androcles wrote:
| | "Ken S. Tucker" wrote in message
| | oups.com...
| | |
| | | Androcles wrote:
| | | "Ken S. Tucker" wrote in message
| | |
oups.com...
| | | |
| | |
| | | | As Sal invited comments, I think, a classical
| | | | explanation is 1 order , followed by the relativistic
| | | | corrections in 2 order.
| | | | Ken S. Tucker
| | |
| | | Totally agree, the presentation given is prejudiced.
| | | Androcles
| | |
| | | Well Sal's a bit smarter and has studied the problem,
| | | but IMO leaning too hard into SR is a push in terms
| | | of theoretics, since an examination of the classics
| | | is the way to at least start.
| | | Ken
| |
| | Like you, sal makes the error of transforming the stationary
| parameters
| | of tau(x,0,0,t) to the moving frame instead of transforming the
| moving
| | parameters tau(x',0,0,t).
| | x' = x-vt,
| | xi = x'/sqrt(1-v^2/c^2),
| | but in the moving frame v = 0, unless you think you can walk
faster
| | than yourself.
| | The cuckoo transforms Einstein blames Lorentz for but wrote
himself
| | are meaningless drivel.
| | Androcles
| |
| | You cannot condemn an entire progran just for
| | a single slip-up!
|
| Why not? I've done it to Henri Wilson and I can do it to Einstein.
| Copernicus did it to Ptolemy, so there is precendent.
|
| Androcles
|
| Sal ran a theoretical experiment, float a balloon
| see where it goes...and he posted that question.
| Ken
|
And got a condemnation for his trouble shrug
Androcles.