If gravity is the effect of spacetime curvature, then why is it stronger on earth than the moon? In other words, it is the curvature of space and time that gives the effect of pulling an object towards a larger object, so once that direction of pull is established why would the size of the larger object (earth) make gravity stronger? Once the direction of pull (due to curve) is established as in DOWN to the earth or moon, why would greater mass make a difference? I read somewhere else that if the earth and moon were closer to the sun, that we would get pulled into the sun. That doesn't seem right. Why isn't mercury pulled into the sun too? I have only seen gravity portrayed as a 2D sheet, but we are in a 3D universe. In which direction is spacetime displaced in space, since space is not a 2D sheet? The sun is displacing spacetime in 3 dimensions, so why does one orbital plane take priority? The sun holds a large planet like Neptune in orbit due to curved spacetime, what keeps it from being pulled closer, or flying away into space?