Document Type
Other
Publication Date
2026
Abstract
Have you ever wondered about the shape of orbits? Are orbits circular? Or maybe they have a different shape? Often when beginning to think about orbits, we think of circular paths, yet that typically isn’t the case. Orbits have two focal points that influence the shape of the ellipse. If the focal points are on top of each other or concentric, the ellipse is a circle.
The planetary orbits have the Sun in one of the two focal points, which is the center of mass for the planetary orbit, according to Kepler’s First Law of Ellipses. The second focal point is called the empty focal point. If the gravity of the sun would suddenly stop, then the focal point would not be present and the object would continue moving in a straight line, according to Newton’s First Law of Motion and the Universal Law of Gravity (NASA, nd.).
Publisher
South Dakota State University
Recommended Citation
Browning, Larry and Cutler, Kay, "Elliptical Orbit Tracing (NASA)" (2026). Astronomy Activites. 6.
https://openprairie.sdstate.edu/recee-astronomy/6