NASA's Dawn spacecraft has returned the sharpest images ever seen of the dwarf planet Ceres. The images were taken 147,000 miles (237,000 kilometers) from Ceres on January 25, 2015. Ceres, the largest body between Mars and Jupiter in the main asteroid belt, has a diameter of about 590 miles (950 kilometers). The mysterious world was discovered in 1801 by astronomer Giuseppe Piazzi. Originally described as a planet, Ceres was later categorized as an asteroid and then reclassified as a dwarf planet in 2006. Some scientists believe the dwarf planet harbored a subsurface ocean in the past and liquid water may still be lurking under its icy mantle.