eccentricity

Eccentricity refers to how much an object's orbit deviates from being circular. In astronomy, it measures the shape of an orbit around a star or planet. A perfectly circular orbit has an eccentricity of 0, while an eccentricity closer to 1 indicates a more elongated, oval shape. This concept is important for understanding the orbits of planets, comets, and other celestial bodies, as it affects their distance from the object they orbit and can influence their speed and behavior over time. Essentially, eccentricity helps describe the variety and dynamics of orbits in the universe.