Which dwarf planet is believed to have harboured a global subsurface ocean that likely froze long ago?

Remnants of an ancient water ocean are buried beneath the icy crust of dwarf planet Ceres — or, at least, lingering pockets of one. That’s the tantalizing find presented August 10 by scientists working on NASA’s Dawn mission. 

By far, Ceres is the largest object in the asteroid belt, which girdles the inner planets between Mars and Jupiter. But unlike its rockier neighbors, Ceres is a giant ice ball. It holds more water than any world in the inner solar except for Earth. That knowledge had long led some astronomers to suspect Ceres may have once had a subsurface ocean, which is part of the reason NASA sent the Dawn spacecraft there.

Ceres is the only dwarf planet in the inner solar system, and it locks up one-third of the entire mass in the asteroid belt. Astronomers think Ceres is a protoplanet, the fossilized remains of a world that never fully formed. But its growth was halted before it could become a full planet. Having such a history means Ceres likely holds an early record of our solar system’s primordial past — hence the name Dawn.

 

Picture Credit : Google