There is a crisis in physics. Gravity can not be properly defined. Quantum mechanics and relativity are too far apart. The gravitons have never been demonstrated.
Dark matter is a mystery. The dark energy and a repulsive force are also great mysteries. A real crisis!
https://pre-bigbang.duckdns.org/cern/
https://pre-bigbang.duckdns.org/einstein-said-gravity-is-not-a-force/