Astronomy‘s Shannon Stirone describes how Ceres has been confirmed as being a water-rich world, if not a world with actual oceans.
Ceres is best known for being the biggest rocky body in the entire asteroid belt, now considered a dwarf planet. The sister to the likes of Pluto, Eris and Makemake, Ceres is turning out to be more complex than scientists initially thought.
When the Dawn spacecraft entered orbit around Ceres in 2015, its mission was to study the planet since it can provide clues about the formation of our solar system and what that environment was like billions of years ago. The team thought they had a chance of finding ice on Ceres, since many asteroids are icy clumps of rock, but they never had evidence of it until now.
In an announcement yesterday at the American Geophysical Union in San Francisco, researchers say they’ve found frozen water ice on the surface of Ceres, stored in its persistently shadowed craters in something called a cold trap.
Ceres, like our moon and Mercury, has a mild axial tilt, so the foot of the craters at their northern regions never see the sun, making sure that whatever water is there, stays put, and it’s likely stayed that way for the last few billion years. The temperature of these craters can get below -260 Fahrenheit, just cold enough that it can take a billion years for the water to turn to vapor.
“These studies support the idea that ice separated from rock early in Ceres’ history,” says Dawn Project Scientist Carol Raymond. “ This separation formed an ice-rich crustal layer, and that ice has remained near the surface over the history of the solar system.”