Asteroid
The dwarf planet Ceres is by far the largest asteroid, with a diameter of . The next largest are 4 Vesta and 2 Pallas, both with diameters of just over . Vesta is the only main-belt asteroid that can, on occasion, be visible to the naked eye. On some rare occasions, a near-Earth asteroid may briefly become visible without technical aid; see 99942 Apophis.
2 Pallas
Both Vesta and Pallas have assumed the title of second-largest asteroid from time to time. At in diameter, Pallas is slightly smaller than Vesta (). The mass of Pallas is only 84% that of Vesta, 22% that of Ceres and about 0.3% that of the Moon.