Richard Feynman: "I want to emphasize that light comes in this form - particles. It is very important to know that light behaves like particles, especially for those of you who have gone to school, where you probably learned something about light behaving like waves. I'm telling you the way it does behave - like particles. You might say that it's just the photomultiplier that detects light as particles, but no, every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering the same thing: light is made of particles."
https://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/0691024170
If Feynman is correct, the wave-based concept of variation of the wavelength of light (illustration:
https://www.youtube.com/watch?v=3mJTRXCMU6o&t=77s) is unrealistic. It makes sense to advance the following
Axiom: The wavelength of light is invariable.
This axiom, combined with the formula (frequency)=(speed of light)/(wavelength), produces the following corollaries:
Corollary 1: Any frequency shift is caused by a proportional speed-of-light shift.
Corollary 2: If the emitter and the observer (receiver) travel towards each other with relative speed v, the speed of light as measured by the observer is c' = c+v, as per Newton's theory.
Corollary 3: Spacetime and gravitational waves (ripples in spacetime) don't exist.
Corollary 4: Light falls in a gravitational field with the same acceleration as ordinary falling bodies - near Earth's surface the accelerations of falling photons is g = 9.8 m/s^2. Accordingly, there is no gravitational time dilation.
Corollary 5: The Hubble redshift is due to light slowing down as it travels through vacuum. The universe is not expanding.
Corollary 6: The dark sky in the Olbers' paradox can be explained by the fact that very slow light coming from very distant sources (known as CMB) is invisible.
More here:
https://twitter.com/pentcho_valev
Pentcho Valev