I think I may have asked this question a few years ago, but I forget the responses. We know that gravity is the curvature of spacetime in the presence of mass and energy.. The curvature of spacetime was proved by experiment during a solar eclipse, whereby light from a star behind the sun was nevertheless observable due to its bending (curving) caused by the sun's mass. Question: Assuming the above statements are true, was the curvature still into the 3rd spatial dimension, or was the curvature into a higher order spatial dimension? What I mean is that for a 2D surface of a sphere, the path followed by a particle or photon along its surface is curved into the 3rd dimension. Why would not 4D spacetime curvature be into the 5th dimension? Balloon analogy, anyone?