Question: How does gravity work and how does the gravitational pull hold us down?

Stefan Lines answered on 12 Nov 2014:

Gravity is one of the most complicated things you can talk about. To explain it, we must invoke Einstein’s General Theory of Relativity. It is unbelievably complex – but I think the most basic way of explaining is that everything in this universe sits on something called spacetime. Masses, such as stars and planets, can bend spacetime, just like a brick would bend a bedsheet. Things close to the object would be sitting on spacetime that was sloping in to that mass and ‘fall’ inwards, which is the equivalent of being attracted to it.