Question: Where does gravity come from

Hayley Evers-King answered on 13 Mar 2013:

This is probably one of the biggest questions science has tried to answer. Simply, gravity is a fundamental property of everything that has mass. Every object with mass is attracted to every other object in the entire universe that has mass. How strong this attraction is depends on the size (mass) of the objects and how close they are to each other. Einstein suggested that gravity was the effect of an object bending space-time. You can think about it a bit like this. Imagine you have a big sheet held up at all four corners and you put a football in the middle. It would bend the sheet – just like Einstein suggested an object would bend space-time. If you then put a tennis ball on the sheet, it will roll down towards the football. This is like how things are attracted by gravity. The situation between the Earth and the sun is quite similar, but a little different. Imagine you roll the tennis ball on to the sheet at an angle, the momentum of the ball will probably make it do a few circles around the football before rolling in smaller and smaller circles towards it. This is basically what we are doing on the Earth, except we are not losing our momentum anywhere near as quickly!!!