text: Yes, with practice it is possible to visualize four dimensional objects. At first it is better to use analogy with lower dimensions. For example, a sphere in three dimensions consists of parallel stacks as follows: a point for the south pole; circles growing until the equator, then shrinking again until you have a point at the north pole. In exactly the same way, a sphere in four dimensions is a stacked collection of three dimensional *spheres*: a point at the north and south poles, spheres growing larger as you move north until the equator (the largest sphere), then shrinking again as you approach the north pole.\n\nAt first, we see the spheres as one sphere expanding and contracting, but if you practice a lot, you can begin to see the whole four dimensional sphere. Similar analogies can be done for 'cubes' in four dimensions and other figures. As others have pointed out, it is possible to use time to help the visualizations. But don't take the 'time is the fourth dimension' stuff too seriously in math. The physics time dimension has properties very different than another space dimension.