The orbits of planets around the Sun are ellipses, with the Sun at one focus.

This means:

* The orbit is not a perfect circle. It's slightly elongated, with the Sun located at one of the two focal points of the ellipse.

* The planet's distance from the Sun varies throughout its orbit. It's closest to the Sun at a point called perihelion and farthest at a point called aphelion.

This law revolutionized our understanding of planetary motion, replacing the older, circular orbit model of Ptolemy.