One of the most interesting concepts is that light cannot accelerate. Light cannot change direction. Light always moves at the exact same velocity.
“18) The Michelson-Morley and Sagnac experiments attempted to measure the change in speed of light due to Earth’s assumed motion through space. After measuring in every possible different direction in various locations they failed to detect any significant change whatsoever, again proving the stationary geocentric model.”
These experiments hoped to show that the ether (please see my prior post about George Biddell Airy) caused some relative difference in the speed of light. Imagine the Earth spinning around the sun and on its axis. It was thought that the speed of light would be change because of this relative motion.
They were unable to measure any relative difference in the speed of light with respect to the ether. Light moved at the same velocity whether it was dawn or dusk and regardless of the time of year. This resulted in the final proof that the ether did not exist. Ultimately, this led to the theory of relativity.
Before jumping to the incorrect conclusion that light does not change velocity because the Earth is not moving like the author, there are two points to consider. Light does not change velocity when measured in a lab; and if the sun was moving over the surface of the Earth, a relative difference in the speed of light would still be expected, unless light did not accelerate.
Later on I may talk some about the theory of general relativity which is one of the most amazing theories of all time.