Speed of light is variable says Einstein

On 11 Aug, 21:59, Tom Roberts wrote:
qbit wrote:
"Tom Roberts" wrote
That 1911 article was documenting a portion of Einstein's arduous trek
from SR to GR. The above formula does not hold in GR,

The above formula of Einstein from the year 1911 is indeed wrong.
Do you happen to know what the correct formula is instead that's
get used in GR?

There is not a single formula, there is only a procedu A measurement
of the speed of light necessarily has two synchronized clocks, a light
source at one clock, a light detector at the other clock, and a ruler
laid along the light path.

Roberts Roberts if you continue teaching idiocies of this kind, even
the silliest zombies in Einstein criminal cult will stop believing
you. Whoever told you that a physical quantity can only be measured
DIRECTLY? Even undegraduates would tell you Roberts Roberts that the
speed of light could be measured INDIRECTLY, e.g. by measuring the
gravitational redshift factor:

http://www.blazelabs.com/f-g-gcont.asp "The first confirmation of a
long range variation in the speed of light travelling in space came in
1964. Irwin Shapiro, it seems, was the first to make use of a
previously forgotten facet of general relativity theory -- that the
speed of light is reduced when it passes through a gravitational
field....Faced with this evidence, Einstein stated:"In the second
place our result shows that, according to the general theory of
relativity, the law of the constancy of the velocity of light in
vacuo, which constitutes one of the two fundamental assumptions in the
special theory of relativity and to which we have already frequently
referred, cannot claim any unlimited validity. A curvature of rays of
light can only take place when the velocity of propagation of light
varies with position."......Today we find that since the Special
Theory of Relativity unfortunately became part of the so called
mainstream science, it is considered a sacrilege to even suggest that
the speed of light be anything other than a constant. This is somewhat
surprising since even Einstein himself suggested in a paper "On the
Influence of Gravitation on the Propagation of Light," Annalen der
Physik, 35, 1911, that the speed of light might vary with the
gravitational potential. Indeed, the variation of the speed of light
in a vacuum or space is explicitly shown in Einstein's calculation for
the angle at which light should bend upon the influence of gravity.
One can find his calculation in his paper. The result is c'=c(1+V/c^2)
where V is the gravitational potential relative to the point where the
measurement is taken. 1+V/c^2 is also known as the GRAVITATIONAL
REDSHIFT FACTOR."

To compute/predict the outcome, one specifies
how the clocks are synchronized, and also the particular null geodesic
followed by the light from source to detector; one integrates the metric
over the paths of the two clocks from their synchronization to their
respective emission and detection events, and then takes the ratio of
the ruler distance to the time difference.

Why isn't there a formula? Because the speed of light
over a non-local path is not a fundamental aspect of the
theory. It is possible to prove that in the limit of
zero distance with Einstein synchronization this
procedure yields the value c, in agreement with SR; this
is independent of location, gravitation, or anything else.

If the light path is so large (compared to the curvature of the
manifold) that no single coordinate system can cover the entire
measurement, the whole notion of "speed" is meaningless.

And Einstein zombie world is speechless Roberts Roberts. I can only
repeat: Bravo Roberts bravo Tom bravo Albert Einstein of our
generation (Hawking is no longer the Albert Einstein of our generation
etc.)!

Pentcho Valev

Measured light speeds:
Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at 299.792.458+-0.001, NOT
measured. No effort to measure the speed will be made since then.


Moreover, the meter and second are both defined based on the speed of
light, so no change in the speed of light can be measured anymore!

Dear DDP3000:

wrote in message
ps.com...
Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a constant, rather
than derived from a manmade length standard.
http://www.mel.nist.gov/div821/museum/timeline.htm

Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of light", but by a
stochastic process where light is emitted.

so no change in the speed of light can be
measured anymore!

True.

David A. Smith

"N:dlzc D:aol T:com (dlzc)" wrote in message
...
Dear DDP3000:

wrote in message
ps.com...
Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a constant, rather
than derived from a manmade length standard.
http://www.mel.nist.gov/div821/museum/timeline.htm

Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of light", but by a
stochastic process where light is emitted.

so no change in the speed of light can be
measured anymore!

True.

Only if you assume light always travels at speed 'c'. If light travels
(say) slower in one situation than another, then you would be able to
measure a difference depending on which particular light you used as your
standard.

On Aug 19, 8:56 am, "Jeckyl" wrote:
"N:dlzc D:aol T:com (dlzc)" wrote in ...





Dear DDP3000:

wrote in message
ups.com...
Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a constant, rather
than derived from a manmade length standard.
http://www.mel.nist.gov/div821/museum/timeline.htm

Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of light", but by a
stochastic process where light is emitted.

so no change in the speed of light can be
measured anymore!

True.

Only if you assume light always travels at speed 'c'. If light travels
(say) slower in one situation than another, then you would be able to
measure a difference depending on which particular light you used as your
standard.- Hide quoted text -

- Show quoted text -

Von Friesen, On the values of fundamental atomic constants and
Petly, The fundamental physical constants and the frontiers of
metrology

On Aug 19, 6:10 am, "N:dlzc D:aol T:com \(dlzc\)"
wrote:
Dear DDP3000:

wrote in message

ps.com...

Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a constant, rather
than derived from a manmade length standard.http://www.mel.nist.gov/div821/museum/timeline.htm

Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of light", but by a
stochastic process where light is emitted.

Actually this is more accurate, but in order to to make the
observation and the measurement a constant c is assumed.







so no change in the speed of light can be
measured anymore!

True.

David A. Smith

Dear Jeckyl:

"Jeckyl" wrote in message
...
"N:dlzc D:aol T:com (dlzc)" wrote in message
...
....
so no change in the speed of light can be
measured anymore!

True.

Only if you assume light always travels at
speed 'c'. If light travels (say) slower in one
situation than another, then you would be able
to measure a difference depending on which
particular light you used as your standard.

Actually, no assumption is required. Because your instrument's
binding forces also cause shrinkage / expansion to match this
anomalous vacuum light speed. Net result is constant c.

Nature won't tell us the difference between "no change" and "all
things change". There is no anisotropy detectable in light cut
off by the Moon even from high z sources, and plenty of
propagation time for the anisotropy to show up. So Nature has
the last say. Doesn't mean we shouldn't look, but I hold out no
hope for finding loaclly variable c, without a medium.

David A. Smith

Dear DDP3000:

wrote in message
oups.com...
On Aug 19, 6:10 am, "N:dlzc D:aol T:com \(dlzc\)"

wrote:
Dear DDP3000:

wrote in message

ps.com...

Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a
constant, rather than derived from a manmade
length standard.
http://www.mel.nist.gov/div821/museum/timeline.htm

Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of
light", but by a stochastic process where light is
emitted.

Actually this is more accurate, but in order to to
make the observation and the measurement a
constant c is assumed.

No. The geometry of an atomic clock is such that a 10% change in
c would have no discernable effect in detected "transistions".
Only if it fluctuated wildly within less than a second could you
(ignoring many other things) be able to detect it. Or if it
varied spatially, such that the light was preferentially lensed
away from the detector.

David A. Smith

On Aug 19, 7:27 pm, "N:dlzc D:aol T:com \(dlzc\)"
wrote:
Dear DDP3000:

wrote in message

oups.com...



On Aug 19, 6:10 am, "N:dlzc D:aol T:com \(dlzc\)"

wrote:
Dear DDP3000:

wrote in message

oups.com...

Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a
constant, rather than derived from a manmade
length standard.

http://www.mel.nist.gov/div821/museum/timeline.htm



Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of
light", but by a stochastic process where light is
emitted.

Actually this is more accurate, but in order to to
make the observation and the measurement a
constant c is assumed.

No. The geometry of an atomic clock is such that a 10% change in
c would have no discernable effect in detected "transistions".
Only if it fluctuated wildly within less than a second could you
(ignoring many other things) be able to detect it. Or if it
varied spatially, such that the light was preferentially lensed
away from the detector.

David A. Smith- Hide quoted text -

- Show quoted text -

Are you sure about this? because it is beyond my knowledge, i have to
take your word for that.

wrote in message
oups.com...
On Aug 19, 8:56 am, "Jeckyl" wrote:
"N:dlzc D:aol T:com (dlzc)" wrote in
...





Dear DDP3000:

wrote in message
ups.com...
Measured light speeds:

Roemer 1675

Birge, 1929, 299.796 km/sec
Mittelstaedt, 1928, 299.778+-20
Michelson et al., 1932, 299.774+-11
Michelson et al., 1935, 299.774+-4
Anderson, 1937, 299.771+-10
Huttel, 1940, 299.771+-10
Anderson, 1941, 299.776+-6
Birge, 1941, 299.776+-4
Dorsey, 1945, 299.773+-10

Since 1972 the speed of light is DEFINED at
299.792.458+-0.001, NOT measured. No effort
to measure the speed will be made since then.

Actually 1983 was when it was established as a constant, rather
than derived from a manmade length standard.
http://www.mel.nist.gov/div821/museum/timeline.htm

Moreover, the meter and second are both
defined based on the speed of light,

No, the second is not defined by the "speed of light", but by a
stochastic process where light is emitted.

so no change in the speed of light can be
measured anymore!

True.

Only if you assume light always travels at speed 'c'. If light travels
(say) slower in one situation than another, then you would be able to
measure a difference depending on which particular light you used as your
standard.- Hide quoted text -

- Show quoted text -

Von Friesen, On the values of fundamental atomic constants and
Petly, The fundamental physical constants and the frontiers of
metrology

eh?