What is the Smallest Planet in the Solar System Mercury is the
smallest planet of the Solar System. This planet was discovered
in the 17th century by the scientist Galileo. Previously, the
Solar System was populated by nine planets and Pluto was
considered the smallest one. However, since the exclusion of
Pluto from the Solar System by the International Astronomical
Union, Mercury, with a diameter of 4,878 Km, is the smallest
planet of the Solar System now. On the other hand, Pluto has
been named as a “dwarf planet”. Among all the eight planets, the
planet with the least distance from the sun is Mercury, being
35,983,046 miles away from the Sun. Such a small distance means
that Mercury takes merely 88 days to finish one orbit around the
Sun; referring to the fact that one year on mercury equals only
88 earth days. Therefore, the smallest planet of the Solar
System also has the smallest duration of the year. However, its
rotation is surprisingly slow. It spins around its axis at a
very slow speed, which is alm