They made the definition of a planet more precise after Ceres and then again when they found even more comparable objects. The definition update that changed Pluto’s category was necessary because it would have added a half dozen new planets if they kept Pluto as a planet.
They made the definition of a planet more precise after Ceres and then again when they found even more comparable objects. The definition update that changed Pluto’s category was necessary because it would have added a half dozen new planets if they kept Pluto as a planet.