Question: Why do we have gravity?

Martin McCoustra answered on 13 Mar 2024:

Isaac Newton was really the first scientist to try and explain gravity… The famous apple on the head story is said to have led him to work out the fact that gravity is the attaction between two masses. He even derived the mathematical relationship for that interaction as an “inverse square law”. However, he really didn’t explain how it works. Einstein got a little close by saying the mass distorts space… so if you imagine space a a flat rubber sheet and put a larger mass in the centre, it will curve the sheet around itself such that small masses will roll towards the larger mass. However, Einstein didn’t manage to put gravity on the same quantum mechanical framework as the other three important forces in the Universe… electromagnetism, the weak nuclear force, and the strong nuclear force that use exchange particles to have an effect. Others are now trying to do this with the idea of gravitons.