The largest asteroid is called Ceres. It is about one-quarter the size of the moon and orbits the sun between Mars and Jupiter in a region called the asteroid belt. Unlike most asteroids, Ceres is spherical in shape. Ceres was discovered by the Italian astronomer Giuseppe Piazzi in 1801 as he searched for a planet which was predicted to exist between Mars and Jupiter. It was the first asteroid ever discovered. It is a dwarf planet.
Ceres was designated a dwarf planet, a new category of solar system objects defined in August 2006 by the International Astronomical Union. (For a discussion of that decision, see planet.) The U.S. space probe Dawn studied the dwarf planet from March 2015 to November 2018. Dawn observed two very bright spots, Cerealia Facula and Vinalia Faculae, in Occator crater on Ceres. The bright spots are highly reflective salts left behind when briny water from an underground reservoir percolated upward and evaporated. The water percolated through fractures left behind when the crater formed 20 million years ago. The salty regions have not been darkened by micrometeorite impacts, indicating that the bright spots formed in the last 2 million years. Because the bright spots contain salt compounds with water that has not dehydrated, the briny water must have percolated upward in the last few hundred years, suggesting that the salty liquid water underneath the crater has not frozen and is perhaps currently percolating from underground.
Credit : Britannica
Picture Credit : Google
