Here's why:

* Eccentricity is a measure of how much an orbit deviates from a perfect circle.

* Eccentricity values range from 0 to 1:

* 0: Represents a perfect circle.

* 1: Represents a parabolic orbit (not closed).

* Orbits with eccentricities closer to 0 are more circular and less elongated.

So, the closer the eccentricity is to 0, the more circular the orbit.