NASA/JPL-CalTech/UCLA/MPS/DLR/IDA
THERE are eight planets in the solar system, according to the International Astronomical Union (IAU), which changed Pluto’s classification from planet to dwarf planet in 2006.
Dwarf planets orbit the sun like regular planets and are big enough to become rounded under their own gravity, but they aren’t massive enough to clear their neighbourhood of other objects, while planets are.
Pluto is the most famous of the dwarf planets, but the solar system is full of objects that meet the classification: a . Officially, though, the
