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 almost equal to 47.8 Km/s. As a result, it takes Mercury around 176 earth days to complete one cycle around its axis making one day on mercury of 176 earth days. The reason behind this slow speed of rotation is the elliptical shape of this planet and the gravitational pull of the sun. Mercury also has the most elliptical orbit among all other planets of the Solar System.

Although planet Mercury is the smallest planet of the Solar System in terms of size, it has quite a high density, which is equal to 5.4 grams per centimeter cube. This high density is because of its composition; Mercury is predominantly composed of iron and rocks. This makes Mercury the smallest, yet the second heaviest planet of the Solar System with Earth being the heaviest one. Furthermore, owing to the fact that it is the smallest planet of the Solar System, it is the hardest one to spot from the Earth. It is only visible for a few days due to its fast speed while moving around the Sun.