Do physicists know that Einstein's constant-speed-of-light postulate is false? Yes:

"Lee [Smolin] and I discussed these paradoxes at great length for many months, starting in January 2001. We would meet in cafés in South Kensington or Holland Park to mull over the problem. THE ROOT OF ALL THE EVIL WAS CLEARLY SPECIAL RELATIVITY. All these paradoxes resulted from well known effects such as length contraction, time dilation, or E=mc^2, all basic predictions of special relativity. And all denied the possibility of establishing a well-defined border, common to all observers, capable of containing new quantum gravitational effects." Joao Magueijo, Faster Than the Speed of Light, p. 250 http://www.amazon.com/Faster-Than-Sp.../dp/0738205257

"...Dr. Magueijo said. "We need to drop a postulate, perhaps the constancy of the speed of light." http://www.nytimes.com/2002/12/31/sc...-relative.html

"So we have broken fundamentally this Lorentz invariance which equates space and time..." https://youtu.be/kbHBBtsrU1g?t=1431

"You want to go back to a notion of space-time that preceded the 20th century, and it wants to ignore the essential lessons about space-time that the 20th century has taught us." Joao Magueijo: "Yes, that's right. So it's nouveau-Newtonian." At 53:29 he http://pirsa.org/displayFlash.php?id=16060116

The problem is that the truth - variable speed of light, as per Newton - will completely destroy fundamental physics. Things will have to restart from scratch:

"The whole of physics is predicated on the constancy of the speed of light," Joao Magueijo, a cosmologist at Imperial College London and pioneer of the theory of variable light speed, told Motherboard. "So we [Niayesh Afshordi and Joao Magueijo] had to find ways to change the speed of light without wrecking the whole thing too much." https://motherboard.vice.com/en_us/a...t-speed-slowed

Afshordi and Magueijo beat about the bush a bit, so in this tweet

https://twitter.com/pentcho_valev/st...89439147859970

I tried to define the situation as clearly as possible. The tweet received a like from... Niayesh Afshordi!

The speed of light is OBVIOUSLY VARIABLE:

Stationary light source, moving receiver: http://www.einstein-online.info/imag...ector_blue.gif

The speed of the light pulses as measured by the source is

c = df

where d is the distance between the pulses and f is the frequency measured by the source. The speed of the pulses as measured by the receiver is

c'= df' c

where f' f is the frequency measured by the receiver.

Pentcho Valev