Relativity was concocted to defend Copernicanism and the theory that the Earth is moving, gyrating, disco-dancing 585 million miles around the Sun, each year. It might be. But the mechancial proof for the Barber of Seville routine in space is very, very thin to non-existent.
Einstein, the great philosophical comedian and artificer, along with many others from the cult of mathematics, concocted the endless abstract inanity of Relativity to deny Michelson-Morley’s 1887 proof from light interference experiments, that no movement of this planet can be found, but an aether wind detected.
STR is false given it does not include gravity, nor an aether. Gravity exists. So does the aether. STR was created to avoid the implications of light experiments which found an aether but no movement of this planet. GTR tried to amend STR by adding in both gravity and a ‘not ponderable’ aether. GTR therefore nullifies STR. GTR is based on circular maths and tautological ‘reasoning’ and explains nothing because it means nothing. The tensor calculus field equations are invalid. When used in reality they derive nothing.