Ceres
The largest object in the asteroid belt, about 940 kilometres across, classed as a dwarf planet since 2006.
Ceres was the first asteroid ever found, spotted by Giuseppe Piazzi in Palermo, Sicily, on 1 January 1801. At about 940 kilometres across, it is big enough for gravity to pull it into a nearly round shape, and in 2006 it was reclassified as a dwarf planet. It holds roughly a third of the asteroid belt's total mass.
Ceres is very different from rocky Vesta. Its low density shows it contains a lot of water, mostly as ice and in water-bearing minerals mixed with rock. NASA's Dawn spacecraft orbited it from 2015 and found bright patches in Occator crater, made largely of salts such as sodium carbonate, probably left behind when salty water from below reached the surface. That makes Ceres an interesting place in the search for watery environments beyond Earth.
No meteorite has been firmly linked to Ceres. Its surface minerals resemble those in some water-rich carbonaceous chondrites, but scientists have not shown that any stone in our collections actually came from it. Through binoculars Ceres looks like a faint star; astronomy apps can show where it is each month.
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Level: Explorer Ages 10 and up