“The three dimensions of length are altered by gravity...”
This is just a nonsense statement. Gravity isn’t “altering” anything. Einstein actually proposed that gravity isn’t even a true force at all, but just an emergent phenomenon created by warping of spacetime. It is mass and energy that warps spacetime (never space) to create the appearance of gravity, NOT the other way around.
The three dimensions of length are altered by MASS-ENERGY just as surely as the fourth dimension of time; in special and general relativity, the only difference between length and time is their opposite signs in the distance metric.