... Eris: The Largest Known Dwarf Planet . ... Is Pluto the largest dwarf planet? ... Eris is just slightly larger than Pluto, but orbits as far as twice Pluto's distance from the Sun. ... The process was part of an inspection to check for damage to the orbiter, but against the backdrop of planet Earth 300 kilometers below, the pictures themselves are stunning. ... The cause, this time, was not a partial lunar phase -- the Moon was full -- but rather that part of the Moon went into Earth's shadow. ...