Do Perfect Circles Exist? Maybe

Can a perfect circle exist? Mathematically speaking, of course. A circle is a collection of points equidistant from a fixed center point, and a simple equation can tell us whenever a shape meets this definition. But in the physical world, things get a bit murkier. It's hard to say with certainty whether a perfect circle or a sphere, a circle's three-dimensional counterpart, exist outside of mathematical abstraction. Why is that? To the human eye, circles and spheres are abundant in nature and in our universe. They can occur naturally - in planets, stars, celestial bodies, tree rings, rain drops - or they can be man-made - such as traffic roundabouts, buttons, volleyballs, pizza. But there is a nuance to what our eyes see as a circle and what math would tell us about their true shape.