Three laws devised by Johannes Kepler to define the mechanics of planetary motion. The first law states that planets move in an elliptical orbit, with the Sun being one focus of the ellipse. This law identifies that the distance between the Sun and Earth is constantly changing as the Earth goes around its orbit.

What is Kepler's Law in simple terms?

1 : a statement in astronomy: the orbit of each planet is an ellipse that has the sun at one focus. 2 : a statement in astronomy: the radius vector from the sun to each planet generates equal orbital areas in equal times.

What explains planetary motion?

Newton's Law of Gravity takes into consideration the masses of two objects and the distance between them. ... Gravity acts across even the enormous distances between the sun and outer planets. The mass of the sun and a planet create a force, pulling the planet's orbit into a circle.