A NASA spacecraft enters orbit around an unexplored world.
On March 6, 2015, NASA’s Dawn spacecraft entered orbit around Ceres, the largest object in the asteroid belt between Mars and Jupiter. Ceres is what scientists call a dwarf planet—a spherical body that likely possesses a differentiated core and crust. Ceres has a diameter of 590 miles and is less than one-tenth the size of the moon. Images of Ceres taken by Dawn during its approach show that like the moon, its terrain is heavily cratered. The images also revealed bright spots on the asteroid that scientists say could be deposits left by liquid water. Ceres is thought to contain at least 25 to 30 percent water, some of which may exist in liquid form beneath its icy surface. Measurements made by Dawn during its one-year mission will provide insights into the composition and internal structure of the asteroid. Watch the video for a close-up look at Ceres.