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Time dilatation in circular motion



 
 
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  #51  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
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Posts: 173
Default Time dilatation in circular motion


"Sam Wormley" escreveu na mensagem
news:tXtTj.96038$TT4.72561@attbi_s22...
El Enrrabadore-mor wrote:
It is said that a speeding clock shows less elapsed time than
the stay-at-home clock, because (if already speeding) it is
running at a slower rate. Or else, because it had run at a
slower rate when it was speeding, assuming now it is
stopped near the stay-at-home clock.


What I meant to say is... for satellite clocks in orbits
approximating circular motion, time dilation is dependent
on altitude in the gravity well as well as relative velocity.
See graph in second link.

Relativistic Effects on Satellite Clocks

http://relativity.livingreviews.org/...age=node5.html
http://relativity.livingreviews.org/...-1/frctfrq.png

Take some time to learn what really happens.



What really happens looks to be the following:
- 98% is Sagnac effect (a non relativistic effect that is said
to contradict SR on its most basic postulate about light)
- 2% is due to all other effects (relativity, excentricities, and so on).

References:
- A QUOTE (from your link):
"GPS can be used to compare times on two earth-fixed clocks when a single
satellite is in view from both locations. This is the "common-view" method
of comparison of Primary standards, whose locations on earth's surface are
usually known very accurately in advance from ground-based surveys. Signals
from a single GPS satellite in common view of receivers at the two locations
provide enough information to determine the time difference between the two
local clocks. The Sagnac effect is very important in making such
comparisons, as it can amount to hundreds of nanoseconds, depending on the
geometry. In 1984 GPS satellites 3, 4, 6, and 8 were used in simultaneous
common view between three pairs of earth timing centers, to accomplish
closure in performing an around-the-world Sagnac experiment. The centers
were the National Bureau of Standards (NBS) in Boulder, CO,
Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, West Germany,
and Tokyo Astronomical Observatory (TAO). The size of the Sagnac correction
varied from 240 to 350 ns. Enough data were collected to perform 90
independent circumnavigations. The actual mean value of the residual
obtained after adding the three pairs of time differences was 5 ns, which
was less than 2 percent of the magnitude of the calculated total Sagnac
effect [4]."




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  #52  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
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Posts: 173
Default Time dilatation in circular motion


"N:dlzc D:aol T:com (dlzc)" escreveu na mensagem
...
Dear El Enrrabadore-mor:

"El Enrrabadore-mor" wrote in message
...
...
Nevertheless, there are two pillar stones in
Physics:
1 - Conservation of Angular Momentum.
(No matter if it is circular motion or linear
motion. For circular motion the conservation
only exists relative to the center of rotation, but
for linear motion conservation exists relative to
every point in space);
2 - Conservation of Energy.

Now, energy is the time derivative of the
angular momentum, and that time is an
absolute time.


No, energy is the path integral of momentum. The energy is a function of
the observer's frame, so it clearly involves *nothing* absolute.


You are right. My mistake, sorry.
It is the other way around:
Momentum is the derivative of energy, or like you
said: "energy is the path integral of momentum".

For linear motion:
Momentum = d/dt Energy
m v = d/dt (1/2 m v^2)

For circular motion:
Angular momentum = d/dt Energy
I w = d/dt (1/2 I w^2)

You're also right about energy being frame dependent.
Nevertheless, for circular motion, in the given example,
I've clearly implied that the center of rotation is a
fixed point in space and it's the origin of the coordinates.
Hence, relative to the center of rotation, my argument
holds 100% :
"Angular momentum is the time derivative of energy
and that time is an absolute time."


How can the above two pillar stones of
Physics survive in view of time dilatation
(and time not being absolute after all)?


Because "absolute" is something artificially impressed by *human*
expectation.


Unfortunately for you, you cannot solve any Physical
problem without that "absolute fixed frame of reference".
You simply cannot solve problems in thin air.
You need a paper for that, where you place an
absolute fixed frame of reference.


David A. Smith




  #53  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
external usenet poster
 
Posts: 173
Default Time dilatation in circular motion


"Greg Neill" escreveu na mensagem
m...
"El Enrrabadore-mor" wrote in message


You've missed the fact that during a given amount
of time a torque T = dL/dt have moved the body a
given angle theta (which is a basic coordinate).


No, I didn't miss anything. A torque doesn't have to
be accompanied by an angular movement any more than
a static force does.


You did miss exactly what you're saying now, but
never mind.


You forget the fact that derivatives are of the form:
d/dt f(x(t)) = x df/dt
x - is an angular displacement

Energy = Torque . angular displacement (dot product)


No. Work is torque x displacement.


I understand if you blame the 'dot product' and replace
it by a simple multiplication sign.
Actually, I've the strong feeling that I've messed up something
about the derivative argument, because what I can get
is a power balance, not an energy balance. Hence,
it is a velocity that comes out, not an angular displacement.

For circular motion:
Work (Kg m^2 s^-2) = Torque (Kg m^2 s^-2) *
* angular displacement (rad)
(relative to the center of rotation).



  #54  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
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Posts: 173
Default Time dilatation in circular motion


"Darwin123" escreveu na mensagem
...
On May 4, 7:31 pm, "El Enrrabadore-mor"
wrote:
"Darwin123" escreveu na
...



On May 3, 2:25 pm, "El Enrrabadore-mor"
wrote:
It is said that a speeding clock shows less elapsed time than
the stay-at-home clock, because (if already speeding) it is
running at a slower rate. Or else, because it had run at a
slower rate when it was speeding, assuming now it is
stopped near the stay-at-home clock.


The funny thing about this is that time and length change
at the same time, but not the ratio between both (velocity).


If we keep length constant, the only possible solution is
uniform circular motion. That is a twin travelling in circles,
of constant radius r, around the first twin assumed to be
stopped at the center of rotation.


Let's say the radius r is a constant value of 100 light-seconds
(r = 100c).
The speeding twin goes on a spaceship at 0.999c.
Therefore, the angular speed 'omega' is v/r = 0.999c/100c
= 0.01 rad/s.
The speeding twin takes 628 seconds to have a complete turn
of 360 degrees.


For small values of t, the speeding twin is almost going in
a straight line, but is fact it has a centripetal force f = m c^2/r
= m c/100, being the centripetal acceleration c/100, towards
the first stopped twin in the center of rotation.


Both twins have powerful antennas that broadcast radio
spherically around the entire space. Both twins are tuned
to each other frequency/radio-station.


Since the distance r = 100c between the emitter and the
receptor is constant, obviously that both twin will hear
each other radio (music) in perfect conditions.


Nevertheless, relativity says that the clock synchronising
the emission of the speeding twin must be running at
a clock rate close to zero. Theoretically, the speeding
twin won't have any trouble receiving the stay-at-home
radio emission, but the stay-at-home twin cannot
receive the speeding twin radio emission, because
the speeding clock is running near zero.
The speeding twin radio emission will take infinite
time to broadcast one single spoken word. The
stay-at-home will be dead by the time the speeding
twin could say a single word.


The trouble seams to be the acceleration:
a = (0.999)^2 c/100 which is about c/100.
(Here the number 100 means 100 seconds).
That's a huge gravity field of 300,000g at
a radius of 100 light-seconds, just imagine
the value it will be at Earth radius based
on the inverse-square Law.)


I presume that such acceleration of 300,000g will
be responsible for a clock speed up rate that
should keep time unchanged after all.
Ys, Einstein proposed this as a thought experiment. However, his
analysis was done using the inertial frame as seen by an observer at
the center of the earth. The moving clock on the edge of the circle
will seem to be slowed down relative to the clock at the center of the
circle, the one that is not accelerating. The clock in the center will
seem speeded up compared to the clock on the circle. However, this
clock is not accelerating.
Yes, the assymmetry come from the centripetal force. The twin in
the center does not experience the centripetal force as the twin on
the circle.
The clocks relative to each other will see differences in the
rate of ticking. The clock with the largest acceleration ticks the
fastest. The other clocks lag behind. However, the clock that
accelerates least (i.e., moves at the slowest tangential speed on the
circle) lags behind the clocks with more acceleration.


Any comments welcome.
This is a description of the Hafele-Keating experiment. The
experiment was performed, and matched Einsteins predictions. Hafele
had two articles in Nature that describe both the experiment and the
analysis of the results. The experiment was performed with atomic
clocks. It is a classic validation of special relativity.


Clearly, your arguments blame acceleration to be the
cause of time dilatation. Fine.

The circular motion at constant angular velocity and
constant radius adds something more.
Not only you have acceleration, but also velocity
relative to any inertial frame of reference nearby.

You cannot add both effects: Velocity + Acceleration
If you sum both effects chances are that you come up
with the conclusion that they cancel each other out.
That's what happens for a stable orbit anyway.

No they don't. They don't exactly speed up. In fact, the
acceleration at some point wins out over the effect of speed.
Where did you get the impression they speed up?


That's what you've said (your words below):
"The clock with the largest acceleration ticks the fastest."
And you keep saying it now, plenty of times, above and
below.


A good approximation of the effect of acceleration on time,
derived from the Lorentz transformation (i.e., SR), is by a
factor (1+ax/c^2). Note this is independent of relative velocity.

a) - Acceleration causes the clock to speed up.
b) - Velocity causes the clock to speed down.
Summing both a) and b) will give what ?

Depends on their relative magnitude. If the factors were the
same, the effect is nothing at all. If the factor for acceleration
is bigger, then there is a total speed up. If the factor for
acceleration is smaller, there is an effective slow down. This is
a problem that must be solved quantitatively. You can't wave
your hand and say "they balance out."


I've a strong feeling they must balance out for a stable orbit.
Stable orbits always balance centrifugal force with the
force of gravity.

1 - Absolute time?

No such thing.


I meant that for a perfect balance among a) and b).

2 - Partially absolute time?

What is that?


That's the case where a perfect balance doesn't exist.
According to your above statements, that should
be the most probable case.

3 - Discard one of the effects and have relativity
time dilatation solution?

Yes. Discard the acceleration and you have the Lorentz
time dilation formula.


Now I'm puzzled.
You've been talking about accelerations all the time.
Now you discard acceleration and step forward?

I bet on conservation of energy, but I was already
told that General Relativity essentially discards nonlocal
conservation of energy.

The same goes for Newton's Laws. An observer in an
accelerating frame of reference, according to Principia,
observes a fictional force that violates the Third Law of
Motion. This fictional force creates a fictional potential
energy that creates a fictional violation of the conservation
of energy and momentum. Key qualifier here is fictional.
Newton's Laws are defined only in nonaccelerating reference
frames. Therefore, the accelerating observer sees a "fictional"
increase in energy, nonlocally.


That's an Invention without any bases.
No such fictional force exists.
I bet "your" fiction requires motion.
No motion, zero work done.

Is it the centrifugal force you are talking about?

No one, ever, could prove Newton wrong, nor
prove any violation of Energy Conservation.

Potential fields are just that: A potential.
No work will be done if no motion exists.

In GR, they replace the words "accelerating reference frame"
by curve in "space-time path". Basically the same thing. The
observer on the curved space time path sees "fictional" changes
in energy.


That should be another relativistic invention.
The word "fictional" says it all.

You need to explain this much better, so that I can
understand what you're talking about.

You can imagine whatever you want, the problem is
to prove that imagination a true fact.

That simply shots down a
Physics pillar stone, but who cares?

Bad metaphor. There was never a "physics pillar stone"
like "nonlocal conservation of energy." See above comment on
Newton's Laws and nonlocal conservation.


I'm still to see a true violation of Newton's Law,
or a violation on "Energy conservation".

Unfortunately, the local process looks to be
irreversible. If it was reversible, non-conservation
of energy locally leads to local free-energy generation.

Actually, it is easily reversible. The rocket enegines turn
off, the observer is no longer accelerating, and energy is
conserved once more even on a nonlocal basis.


If you had an energy lost during acceleration,
during de-acceleration you've reverted the sign.
Mathematics and simple logic says you should see
a gain in energy.

Please respond.



  #55  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
external usenet poster
 
Posts: 173
Default Time dilatation in circular motion


"Ken S. Tucker" escreveu na mensagem
...

Use h = energy*time, = E*t = E'*t' then
E' = (t/t')*E,
Fortunately "h" is a universal constant and
invariant.
Two different observers can disagree on the
measurement of E and E', and t and t', but
they agree on the product "h".


It is good to know that observers can agree on
something.
You've made some good points Ken.
Regards.

Regards
Ken S. Tucker



  #56  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
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Posts: 173
Default Time dilatation in circular motion


"bz" escreveu na mensagem
98.139...
"El Enrrabadore-mor" wrote in
:


"Tom Roberts" escreveu na mensagem
...

One can analyze their experiment (including comparison to muon decay at
rest) in two different ways:
a) use the overall inertial frame of their storage ring
and apply SR.
b) use the equivalence principle of GR, and treat the LOCAL
acceleration of the stored muons as a gravitational field
and compute the gravitational time dilation in LOCAL
coordinates in which the stored muon is at rest.
These obtain the same answer.


Moreover:
Your a) appeals on velocity as the cause of
time dilatation.
Your b) appeals on acceleration (or gravity
by equivalence principle) to be the cause on
time dilatation.


It is not the velocity or the acceleration (in SR) that explains the time
difference.
It is the different trajectory.
Trajectory through space-time.


And that space-time is a Gaussian coordinate
system made of curved lines like two orthogonal
mirror spirals?

Please explain Bob.



Physics say:
c) Acceleration is the time derivative of velocity.

My c) proves your a) and b) to be incompatible,
since time used on the derivative is ABSOLUTE
TIME.


a = dv/dt says nothing about ABSOLUTE time.

Where did you get the impression that it did?

dt is CHANGE in time.



I wonder how derivatives will be if the said changing
time had been already affected by time dilatation.

Just imagine that velocity changes.
Time dilatation will change too.
You get a derivative where time himself changes.
What a mess I presume.


  #57  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
Dono
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Posts: 3,751
Default Time dilatation in circular motion

On May 5, 9:19*am, "El Enrrabadore-mor"

What really happens looks to be the following:
- 98% is Sagnac effect (a non relativistic effect that is said
to contradict SR on its most basic postulate about light)



The Sagnac effect does not contradict SR. You are an imbecillic troll
  #58  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
El Enrrabadore-mor[_2_]
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Posts: 173
Default Time dilatation in circular motion


"Dono" looking for an Enrrabadore spew in the message:
...

The Sagnac effect does not contradict SR. You are an imbecillic troll


In Sagnac experiment, light speed is *measured* not to be
independent from either, the source and the observer.
That's so obvious and so many times proved, by
so many, that it should hurt very bad. Doesn't it Dono?

Of course, nothing that one cannot re-arrange, like
making 1+1=3 should be easy for any good relativist
using a convenient coordinate system, perfectly engineered
for the show-off.

Now, please send the "jpg" pictures. Got new ones?





  #59  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
Dono
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Posts: 3,751
Default Time dilatation in circular motion

On May 5, 11:04*am, "El Enrrabadore-mor"
wrote:
"Dono" looking for an Enrrabadore spew in the ...

The Sagnac effect does not contradict SR. You are an imbecillic troll


In Sagnac experiment, light speed is *measured* not to be
independent from either, the source and the observer.



No, it isn't. This means that you are both an imbecile and a troll.




  #60  
Old May 5th 08 posted to sci.physics.relativity,sci.physics
dlzc
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Posts: 1,464
Default Time dilatation in circular motion

Dear El Enrrabadore-mor:

On May 5, 9:19*am, "El Enrrabadore-mor"
wrote:
"N:dlzcD:aol T:com (dlzc)" escreveu na ...

Dear Greg Neill:


"Greg Neill" wrote in message
om...
...
No, in a propagating transverse electromagnetic
wave *may be orthogonal, but they are in phase.


In a vacuum they are in phase. *As a medium in
interposed, the phase relationship changes.
*When bound to a conductor, and "pushing" charges
around, they are 90 degrees out-of-phase.


From my knowledge on power generation, the electric
and magnetic fields are 90 degrees out-of-phase
if no mechanical energy is converted into electric
power.


That is what pushing electrons (with their mass... remember simple
harmonic motion?) does.

...
Couldn't it be the case that electromagnetic
radiation in vacuum interacts with sensors
in-phase for an unitary power factor (and zero
losses)?


No. The rest of the physics doesn't work.

David A. Smith

 




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