how the “bending space-time” visualization of gravity works/looks like in 3D space? (i.e. gravity is often visualized with a picture of a flat sheet-like plane, with a round object sitting on that plane and bending it so that objects roll towards the object).

Question

Obviously gravity isn’t acting on a 2D plane or objects would gravitate to the “bottoms” of other objects. I’m curious about whether there is a way to visualize how this model works in 3D.

In: Physics

Answer 1

If you imagine a 3D grid around a massive object, it will distort and bunch together toward the massive body.

Any arbitrary 2D slice of this 3D grid (taken through the center of the massive body) will look the same, and appear as if you were looking straight down on the 2D sheet visualization.

In 3D the “gravity well” is the same as in the 2D visualization, except “downhill” is “toward the center” instead. It’s omnidirectional.

Yes, it’s only an analogy and doesn’t capture the full complexity, but it’s still a good analogy.