Re: Mercury's perihelion precession and the reason why GR is badly wrong

On Jun 19, 9:01 pm, "JM Albuquerque" <jmDO...@xxxxxxxxxxx> wrote:
"Darwin123" <drosen0...@xxxxxxxxx> escreveu na mensagemnews:a751095d-ce3c-44d3-b70b-358beffb82eb@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx



On Jun 17, 7:18 pm, "JM Albuquerque" <jmDO...@xxxxxxxxxxx> wrote:
"Eric Gisse" <jowr...@xxxxxxxxx> escreveu na
mensagemnews:cbf1dfab-5a33-47f4-b07c-30423d752406@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Is the moment of inertia the same in relativity and Newton for a
neutron star which is gravitationally hyperbound ?
No. However, the neutron star still has a moment of inertia in
both theories. It will have a higher moment of inertia in relativity.
Did anyone tell you the moments of inertia have to be the same?
True, the particles in a gyroscope have a finite rest mass. >>However, no particle in any real gyroscope moves at the speed of light. Therefore, there is no problem.

I agree, there is no problem, but there is for sure a topic
on physics to discuss.
A topic of physics, but not a problem in physics.
There is no known way, even in principle, to spin a gyroscope so
the edge moves at the speed of light. The larger the speed, the larger
the inertial mass, and the larger the moment of inertia. Thus, to spin
a gyroscope to the speed of light requires infinite energy. Since in
principle there is no source of energy that is infinite, there is no
problem.

People keep claiming that Sagnac interferometer agree with
relativity when it clearly, since the beginning, refutes relativity
postulate about the speed of light independent on the observer's
speed. That's so clear and obvious that I always though about
that relativity claim as a joke.
It so obviously does agree with relativity that I suspect you
mean that as a joke. The Sagnac does not at all violate the relativity
postulate that the speed of light is independent of the observers
speed.
Lets look at the situation from the standpoint of an inertial
observer located at the exact center of the Sagnac cavity. There are
two waves circulating in opposite directions in the Sagnac
interferometer. If the cavity is a vacuum, the two beams are moving at
the exact same velocity, which is the speed of light (i.e., c) in a
vacuum.
The two beams are different, although not in speed. The
relativistic Doppler shift shows how the moving mirrors changes the
frequency of each beam. One beam is Doppler shifted up in frequency,
and the other is Doppler shifted down in frequency. Each beam has a
different frequency, and therefore a different wavelength as seen by
the inertial observer.
However, both beams are moving at the speed of light, c. There
is no difference is speed of light. What is measured is a difference
in frequency, not a difference in the speed of light.
What comes out of the Sagnac interferometer is a light beam that is
modulated in time by the difference between the two frequencies. These
are called beats, and are a standard part of even nonrelativistic
physics. When you superimpose two light signals of different
frequency, one gets beats. The beat frequency is either the difference
or the sum of the two frequencies. It so happens that the difference
in frequencies between the two light beams is so small, that the
difference in frequency is easily measured by electronic means. Note
that no where in my description is a light beam traveling at any other
than the speed of light.
In special relativity, the Sagnac interferometer is easily
explained as a consequence of relativistic Doppler shift. The mirrors
are moving relative to the laboratory frame. Therefore, both the
wavelength of the beams and the frequency of the light reflecting off
them has changed for the inertial observer. The Sagnac interferometer
is basically measuring the difference in frequency between the two
beams as measured at the same mirror (i.e., where the light partially
leaks out). There is no rule in special relativity about two
frequencies having to be the same.
I suspect there is a half truth in your description of the Sagnac
interferometer. You may have read a description performed in something
other than an inertial frame. If one performs the calculation from the
standpoint of an observer rotating with the cavity, the description
may be different. That involves either general relativity or some
really fancy mathematics with special relativity. However, the
rotating reference frame is not an inertial frame. The rule concerning
invariance in the speed of light only applies to inertial frames. So
someone who explains it using a rotating frame may end up describing a
difference in the speed of light. However, he is only correct for a
rotating frame.
In an inertial frame, for either GR or SR, the speed of light is
independent of observer. However, this is only true for an inertial
frame.
If one works at it one can analyze the SI cavity as a type of
relativistic gyroscope. The moment of inertia of the two light beams,
which are analogous to the wheel of a gyroscope, is finite. Again, no problem.
OOOOYYYY.
Sagnac a gyroscope?
There is a huge problem.
Okay, maybe the Sagnac interferometer is not a gyroscope. I may
have stretched that analogy too far. This isn't a true precession,
since the beats don't oscillate in space.

I wish to discuss Sagnac interferometers just to avoid a point that
may confuse some people. The Sagnac interferometer (SI) in some ways
acts like a gyroscope.
I am not sure about that anymore. I have not worked out the
equivalence between the two theories. However, I have looked at the
physics of the Sagnac interferometer and there is no contradiction
with special relativity.
I have even looked into the analysis of Professor Charles Ives
concerning the Sagnac. Charles Ives analysis is wrong. This has been
shown both theoretically and experimentally. But a lot of hacks keep
bringing it up.
.

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