I was contemplating the size and shape of the universe. Our observable universe is perfectly 3D spherical, but that's a result of a finite speed of light and a beginning of time, and I was wondering if there was a way to deduce the size of the universe. I imagined the universe as a 4D sphere then imagined myself traveling through it, what would I see. Over small distances and speed I would see the universe as 3D, but at high speeds and over massive distances, the curvature should become apparent and I had a wondering. Say we send telescopes away from earth in opposite directions and point them at exactly the same orientation towards an object at the edge of the observable universe. In a 3D space, they would appear in exactly the same location minus a small shift to account for parallax. In 4D space, the extremely distant objects should appear to move both in space and time, and the amount that they move would be directly relational to the distance between the viewpoints, the distance to the object, and the size of the universe. Am I correct, or would the fact that light travels along the curvature of space made it appear as though it was 3D even if it were curved? I had this thought because I imagined moving at high speeds through a 4D sphere and what I would see, and I would see something very similar to the Lorenz transformation and it made me wonder if the universe could be a 4D sphere.