Question

observable universe is eliptical or circle

Answer 1

circle is a two dimensional geometry and ellipse is also two dimensional and the criteria scientists uses to determine the shape of planet for example earth has shape The oblate spheroid, or oblate ellipsoid, is an ellipsoid of revolution obtained by rotating an ellipse about its shorter axis. so the observable universe is the rotation of ellipse by its different axis

Answer 2

We don't exactly know the geometry of the universe, but one possibility is that it is a hyper-sphere. Here's how Nobel laureate Leon Cooper explained it in a study:

Think about the surface of a sphere. If you are living on the surface of a sphere, as we are on earth, you can travel in what appears to be a straight line, and eventually end up back where you started, because you've traversed the entire circumference. If you draw two points on the surface of a sphere, and then expand the sphere (he demonstrated this with a balloon), they get farther apart even though their position on the sphere didn't change.

The surface of a sphere is a 2 dimensional surface in 3 dimensional space. The universe may be a 3 dimensional surface in a higher dimensional space. The universe can thus possess a finite volume and "expand" without having edges. It would hence theoretically be possible to travel in a relatively straight line in space, and end up straight back at where you started.