speed of light

light is the fastest thing in the universe.(maybe).light can go up to about 300,000 km a second.

yes...

i have to concur with the honorable gentleman, yes...

That is because the evidence indicates they would be wrong.

(1) The erroneous measurements of manufactured neutrinos turned out to support speeds just under the speed of light when the mistake was corrected.

(2) Photons and neutrinos arrived from SN1987A almost in synch, and the couple of hours delay was explained by the delaying of the light by matter outside the core of the star.

It's worth emphasising that even the 2-3 hours delay was scarcely more than one part in a billion of the transit time!

[COMMENT DELETED]  Given that you are so sure that neutrinos can not go faster than C;  it may not be 10 years , but 15 years until that is accepted.

So presumably your superluminal neutrinos have only been observed inside your head?

the speed of light may have been higher in the past. Astronomers have discovered that billions of years ago the positions of electrons in the energy levels were slightly different to how they are now. The position of electrons in the energy levels are governed by several scientific constants so any change in this means one of the constants has changed. This could include the speed of light.

I don't think that is an accurate description of the current state of knowledge.

To me, there is no room for a variable speed of light in physics. Space-time has a Riemannian metric with signature +++-. All such metrics look the same: c is simply the way in which scales in the - direction are compared to scales in + directions.

If you moved through space-time and c varied you would have no way of telling. It is only if a dimensionless constant varies that you can tell.

So if there is some claim that a dimensionless constant has varied, that is another thing. Perhaps alpha? Or the Planck mass?

I'm probably wrong here, but it seems that if c were variable, one could design a non-local experiment to detect that. In local space-time, I agree, it would seem to be undetectable. Need to think on that a bit more, though. Nice stuff, Elroch!

There are hundreds of non-local experiments.  Every galaxy system needs stronger gravity to explain the results.  If more gravitons are exchanged in a given time than one now expects, the gravity is stronger.  More gravitons are exchanged in a given time if they go FASTER.  That's a different C.  What is extra special about this idea is if it is true about gravitons, it is true about gluons.  Try to explain how a proton in a collider moving at the speed of light is stable if the gluons are only moving at C too.

Gee;  4 months later and on one tried.   Pretty hard , isn't it !!!!    (from below)   "Obviously all quantum mechanics would change with c."     YES, in fact ALL physics changes  if C changes.  THAT is why we have DIFFERENT BIG BANGS.

True, if some distance remained known to be fixed while c changed. But this would be an odd interpretation of c staying the same and the distance changing.

Obviously all quantum mechanics would change with c, which would change all rulers based on quantum mechanical scales (eg wavelength of emitted photons, diameter of atoms).