The sun is the most perfectly round natural object known in the universe, say scientists who have conducted precise measurements of its dimensions. As a spinning ball of gas, astronomers had always expected our nearest star to bulge slightly at its equator, making it very slightly flying-saucer shaped.

What planet has a perfect sphere shape?

Mercury and Venus are the roundest of all. They are nearly perfect spheres, like marbles. But some planets aren't quite so perfectly round. Saturn and Jupiter are bit thicker in the middle.

What is a perfect sphere?

A perfect sphere is defined as being completely symmetrical around its center, with all points on the surface lying the same distance from the center point.