Eris is more massive than Pluto but has a smaller volume ... planet – and that it has a mass higher than 10 kilograms (2.2 x 10 pounds). No prize for guessing that Pluto and Eris are too ...

The other four dwarf planets in the solar system are Ceres, Haumea, Makemake and Eris ... X resumed in 1929, this time with 23-year-old Clyde Tombaugh at the helm. He discovered Pluto a year ...