the nature of gravity in the sense of how it works in a 3D universe

Question

I need help with an analogy here because I simply don’t know/can’t visualise the true physics here.

Many people use an analogy for gravity acting on space-time as a sheet of material stretched across a plane and a heavy object in its center acting as a celestial body.
This is great for envisioning orbits, the curvature of spacetime and so on.

Now this is a “2D” sheet/plane that deforms “downward” in the 3rd dimension, I get it… But how does it translate to the actual universe? The universe is always 3D in all directions, isn’t it?

I’m stuck here guys, science help me!

In: 81

Answer 1

Try this PBS Spacetime episode for why time dilation can lead to the observed effect of gravity.

And if you want to know even more, here’s one about how gravity causes time dilation. I think this is even the episode that says how inadequate an analogy the bowling ball on a sheet is.