NASA: Dwarf planet Ceres is an ocean world

Scientists considered Pluto to be a planet when it was discovered, but it later became the first dwarf planet. It’s not the closest one to Earth, though. Ceres is a dwarf planet and the largest object in the Great Asteroid Belt, and it has a new distinction today: ocean world. The latest data from NASA’s Dawn mission proves the almost-planet has a vast repository of salty water hiding below its surface. That makes it a possible home for life in the solar system. 

NASA’s ion engine-powered Dawn spacecraft visited Ceres in 2018, getting as close as 22 miles (35 kilometers) from the surface. Images from Dawn’s approach stirred interest when they showed several bright spots in the 57-mile (92 kilometers) Occator Crater. The entire planetoid is only 590 miles (950 km) in diameter, so this crater is quite prominent. 

The team identified two sources of salt deposits on Ceres. The first was a slushy pool of brine just below the surface. Ceres doesn’t have any internal geological heating, but the impact that formed Occator Crater liquified the water. That puddle cooled after a few million years, but the impact also produced fractures that extend deep into the surface. The fractures intersect a larger, long-lived reservoir of brine further down. Over time, that allowed more brine to seep up to the surface where it evaporated and left behind more salt.