Asteroids. Ceres

Asteroids are minor planets, especially of the inner Solar System. Ceres is the largest object in the main asteroid belt that lies between the orbits of Mars and Jupiter. With a diameter of 940 km (580 mi), Ceres is both the largest of the asteroids and the only dwarf planet inside Neptune's orbit. It is the 25th-largest body in the Solar System within the orbit of Neptune. Ceres was the first asteroid to be discovered (by Giuseppe Piazzi at Palermo Astronomical Observatory on 1 January 1801). It was originally considered a planet, but was reclassified as an asteroid in the 1850s after many other objects in similar orbits were discovered. Ceres is the object in the asteroid belt closest to being fully rounded by its own gravity, although Vesta and perhaps other asteroids were so in the past.