The speed of light is OBVIOUSLY variable, e.g. relative to the moving observer in Doppler: https://youtube.com/watch?v=bg7O4rtlwEE. So theoretical physicists do know the truth but continue to teach the lie. Why? The reason is simple. Modern physics is predicated on Einstein's constant-speed-of-light falsehood and will collapse without it. In this regard, establishing the truth would be suicidal:

"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 had to find ways to change the speed of light without wrecking the whole thing too much." https://motherboard.vice.com/en_us/article/8q87gk/light-speed-slowed

See more here: https://twitter.com/pentcho_valev

Pentcho Valev

Sabine Hossenfelder: "Today I want to tell you how particle physicists are wasting your money" https://youtu.be/9qqEU1Q-gYE?t=3

The more-than-a-century reign of the insane ideology called "relativity" is by far the biggest waste of money in the history of science. Just an example:

Gamma rays are gravitationally deflected or blocked by cosmic matter. Gravitational waves are not, Einsteinians teach:

"Unlike light, gravitational waves don’t care about matter in any way. You can pass gravitational waves through the vacuum of space, through a lens, prism, or other material, or even through the solid Earth itself, and they will continue to propagate at the speed of gravity." https://www.forbes.com/sites/startswithabang/2020/12/24/how-gravitational-waves-might-wind-up-proving-einstein-wrong/

Therefore, gamma rays and gravitational waves CANNOT arrive "from the same location of the sky", just two seconds apart:

"On 8:41 am EDT August 17, 2017, LIGO detected a new gravitational wave source, dubbed GW170817 to mark its discovery date. Just two seconds later NASA's Fermi satellite detected a weak pulse of gamma rays from the same location of the sky." https://www.cfa.harvard.edu/news/2017-30

The speed of light is VARIABLE AS PER NEWTON, as originally ("without recourse to contracting lengths, local time, or Lorentz transformations") proved by the Michelson-Morley experiment:

"Moreover, if light consists of particles, as Einstein had suggested in his paper submitted just thirteen weeks before this one, the second principle seems absurd: A stone thrown from a speeding train can do far more damage than one thrown from a train at rest; the speed of the particle is not independent of the motion of the object emitting it. And if we take light to consist of particles and assume that these particles obey Newton's laws, they will conform to Newtonian relativity and thus automatically account for the null result of the Michelson-Morley experiment without recourse to contracting lengths, local time, or Lorentz transformations. Yet, as we have seen, Einstein resisted the temptation to account for the null result in terms of particles of light and simple, familiar Newtonian ideas, and introduced as his second postulate something that was more or less obvious when thought of in terms of waves in an ether." Banesh Hoffmann, Relativity and Its Roots, p.92 https://www.amazon.com/Relativity-Its-Roots-Banesh-Hoffmann/dp/0486406768

This implies that Einstein's spacetime does not exist and neither do LIGO's gravitational waves (ripples in spacetime).

More here: https://twitter.com/pentcho_valev

Pentcho Valev