Question: Why does gravity have to go down why not up,left or right?

Jen Gupta answered on 17 Jun 2011:

OK the simple way to answer this is to ask you “what do you mean by down?” 🙂

If you think of gravity as pulling us down towards the centre of the Earth, you can draw an arrow from you to the centre of the Earth and label it as “down”. But if you kept that arrow going through the Earth and onto the other side, it would be pointing up for someone standing on the opposite side of the planet!

Gravity is an attractive force so it pulls things together. Because the Earth has lots of mass, the Earth’s gravity pulls us towards its “centre of mass” which is in the middle of the planet. We feel this as a force “down” but someone on the other side of the Earth would feel gravity in the opposite direction to us because they are on the opposite side of the centre of mass. It’s gravity that makes our planet orbit around the Sun, and makes the Sun orbit around the centre of the Milky Way.

I hope that makes sense!