# The Speed of Light is Not Constant

http://mathpages.com/rr/s2-07/2-07.htm
extract:
Despite the ease and clarity with which special relativity accounts for the Sagnac effect, one occasionally sees claims that this effect entails a conflict with the principles of special relativity. The usual claim is that the Sagnac effect somehow falsifies the invariance of light speed with respect to all inertial coordinate systems. Of course, it does no such thing, as is obvious from the fact that the simple description of an arbitrary Sagnac device given above is based on isotropic light speed with respect to one particular system of inertial coordinates, and all other inertial coordinate systems are related to this one by Lorentz transformations, which are defined as the transformations that preserve light speed. Hence no description of a Sagnac device in terms of any system of inertial coordinates can possibly entail non-isotropic light speed, nor can any such description yield physically observable results different from those derived above (which are known to agree with experiment).

So the mathematics say

But what of the PRACTICAL

arbitrary Sagnac device

The experiment by Sagnac was a real experiment

So the mathematics say

But what of the PRACTICAL

river doing the river thing again.....grasping at straws.

river doing the river thing again.....grasping at straws.

Hmmm....

Straws is it

Hmmm....

Straws is it

http://www.researchgate.net/publica...nac_effect_correct_and_incorrect_explanations
ABSTRACT Different explanations for the Sagnac effect are discussed. It is shown that this effect is a consequence of the relativistic law of velocity composition and that it can also be explained adequately within the framework of general relativity. When certain restrictions on the rotational velocity are imposed, the Sagnac effect can be attributed to the difference in the time dilation (or phase change) of material particle wave functions in the scalar (or correspondingly vector) gravitational potential of the inertial forces in a rotating reference system for counterpropagating waves. It is also shown that all the nonrelativistic interpretations of the Sagnac effect, which are unfortunately sometimes found in scientific papers, monographs and textbooks, are wrong in principle, even though the results they yield are accurate up to relativistic corrections in some special cases.

Don't worry river, it's always nice to see you and wearing your anti establishment heart on your sleeve.
Brings a tear to one's eye and a lump to one's throat.

Interesting

When certain restrictions on the rotational velocity are imposed

Hmmmmm....

Interesting

When certain restrictions on the rotational velocity are imposed

Hmmmmm....

When certain restrictions on the rotational velocity are imposed the Sagnac effect can be attributed to the difference in the time dilation (or phase change) of material particle wave functions in the scalar (or correspondingly vector) gravitational potential of the inertial forces in a rotating reference system for counterpropagating waves.

When certain restrictions on the rotational velocity are imposed the Sagnac effect can be attributed to the difference in the time dilation (or phase change) of material particle wave functions in the scalar (or correspondingly vector) gravitational potential of the inertial forces in a rotating reference system for counterpropagating waves.

Can be ....but in reality are they ?

Can be ....but in reality are they ?

You are making the claim...The onus is on you to show they do not.
In other words, please show us an experiment which conclusively shows that the speed of light is not constant.
I'm waiting.

You are making the claim...The onus is on you to show they do not.
In other words, please show us an experiment which conclusively shows that the speed of light is not constant.
I'm waiting.

Sagnac experiment

Sagnac experiment

Please explain how an objects mass increases as it nears the speed of light. What would you see if the object were a space ship and you were close to it

What would you see if you were close to a spacecraft that was going close to the speed of light when its mass starts to increase

What would you see if you were close to a spacecraft that was going close to the speed of light when its mass starts to increase

From any remote FoR, you would see the a clock on the ship, ticking slower, and the ship would appear shorter in the direction of travel, and if you could weigh it, it would be heavier.

Please explain how an objects mass increases as it nears the speed of light. What would you see if the object were a space ship and you were close to it

Its mass does not increase. Its momentum increases. The now old and often misunderstood concept of relativistic mass, is misleading, in a lay context.., and best avoided.

It is best to stay with rest mass and momentum, in discussion. Rest mass is constant and momentum is relative to frame of reference.

Please explain how an objects mass increases as it nears the speed of light. What would you see if the object were a space ship and you were close to it

You wouldn't see anything unusual if you were travelling along beside that space ship, matching it's speed, because this is an effect of relative velocities. So, you'd have to look at it or otherwise interact with it as it raced past you at a good fraction of the speed of light.

I suppose that, in theory, you could try giving it a push as it raced past (or try to stop it), and measure the effect of the applied force on the object's motion. What you'd find is that your push produces less acceleration of the spaceship than when it is going at low speed. That is, the spaceship acts as if it has more inertia.

That is, the spaceship acts as if it has more inertia.

I am no longer certain that inertia in a relativistic context is an entirely accurate term... Because it would take less force to reduce its velocity by a given amount than it would to accelerate by the same amount. Which would suggest that the spaceship has more inertia in one direction, the direction of its motion.., than in any other direction. This may be a situation similar to rest mass, relativistic mass and momentum.

At classical velocities inertia is isotropic for all changes in velocity. Where at relativistic velocities it takes more added force to accelerate, than it does to decelerate.