Johannes Kepler's work in astronomy mainly dealt with what aspect of orbiting objects?

a The masses of the objects in orbit
b Their orbiting motion and the shape of the orbital paths
c Their orbit sizes and the contraction and expansion of those orbits
d The orbital speeds and how the masses affect their speeds

1 answer

Johannes Kepler's work in astronomy mainly dealt with b) Their orbiting motion and the shape of the orbital paths. Kepler is best known for formulating three laws of planetary motion, which describe the elliptical orbits of planets, the relationship between the distance of planets from the sun and their orbital periods, and the areas swept out by a planet in its orbit.