It's really not difficult if you just consider what a dimension really represents...a degree of freedom. So a 4th spatial dimension for us would be as if each p

It's really not difficult if you just consider what a dimension really represents...a degree of freedom. So a 4th spatial dimension for us would be as if each point in our 3d space had a hole at the center of it. The 4th dimension is inside of every point. Lets say this 4th dimension is not infinite and is only 1 meter long. Then each of these holes would be 1 meter deep. The 4th dimension is just the result of replacing each point in 3d space with a line. If you start with a point, and you recursively replace all points (not just endpoints), with perpendicular lines (no overlap with existing points), you'll have a simple process that constructs higher and higher dimensions. It's possible that gravity originates from a 4th spatial dimension and thus appears to be radiating outward isotropicly from the center of all matter.