Ceres is the earliest known and smallest of the current category of dwarf planets. Sicilian astronomer Giuseppe Piazzi discovered Ceres in 1801 based on the prediction that the gap between Mars and Jupiter contained a missing planet. It is only 590 miles (950 km) in diameter and has a mass of just 0.015 percent that of Earth.
In fact, Ceres is so small that it is classified as both a dwarf planet and an asteroid, and is often named in scientific literature as one of the largest asteroids in the solar system. Although it makes up approximately a fourth of the mass of the asteroid belt, it is still 14 less massive than Pluto.
NASA’s robotic Dawn mission arrived at Ceres in 2015. The mission has shown many interesting features on its surface, ranging from various bright spots to a 4-mile-high (6.5-kilometer-high) mountain. (Another mission, the European Space Agency’s Herschel Space Observatory, spotted evidence of water vapor in 2014.)
Picture Credit : Google