I am confuse, here, a theory!!!, its weird because of all the crash i suffer in my many years of mountain biking and pain i suffer from today are cause by gravity, also , here a simple experiment , take a bicycle wheel , 26 inch preferably, spin it as fast as you can, now sit on a office chair with wheel and you hold it at arms lenght , in theory you should start spin in a clock wise direction ( earth direction ) , after this let me know if gravity is just a theory , also you can ask all the poor muslim gay man who were thrown off the roof of high rise building
Gravity is a force, not a theory