Most people know that the Earth orbits the Sun in an ellipse, rather than a circle, but the value of the Earth’s orbital eccentricity is approximately equal to 1/60. A planet that orbits its sun periodically always has an eccentricity between 0 and 1, including 0 but excluding 1. An eccentricity of 0 means the orbit is a perfect circle with the Sun at the center and the planet orbiting at a constant speed. However, such an orbit is extremely unlikely as there is a continuum of possible eccentricity values. The eccentricity, in a closed orbit, is measured by dividing the distance between the Sun and center of the ellipse by the length of the semi-major axis of the ellipse. The orbit becomes increasingly longer and thinner the closer the eccentricity gets to 1. The planet always orbits fastest when it’s nearest to its Sun and slowest when it’s farthest from its Sun. When the eccentricity is greater than or equal to 1, the planet comes around its Sun once and flies back out into space never to be seen again. --listverse
Linkback:
https://tubagbohol.mikeligalig.com/index.php?topic=45297.0