### Gravitation - Pulling or Pushing force?

• According to Newton, gravity is the pulling - or in fact the attracting - force of any heavenly body towards any object to its center. But, to the contrary, Einstein once said that the four dimensions of space and time push the object downwards.

So can which one of them is correct?

It's a mistake to think that Newton identifed gravity as a pull: see quotations from Newton in my answer below.

In physics there is no such thing as a distinction between pulling or pushing forces. Forces are acting on something, this action can be expressed in terms of equations, that's it.

7 years ago

In general relativity, gravity neither pushes nor pulls. To explain why ball travels in an arc you note the start and end points of the throw in 4d space time (3 space co-ordinates and 1 time coordinate) You then find the shortest path between these two 4d points in the curved spacetime surrounding the Earth. This shortest path is the path in spacetime that the ball travels.

So in General relativity, gravity is not seen as being a force, instead it is the result objects travelling in the most direct way in a region of curved spacetime.

However for nearly all practical purposes, the effect of gravity in relativity is amost identical to that produced by an attractive force, as supposed by Newton.

In Lorentzian spacetime, geodesics are locally longest paths, rather than shortest as in Riemannian space. This reversal is due the different signature of spacetime metric compared to a purely spatial one.