Nestled in the asteroid belt, the dwarf planet Ceres contains water-rich materials that suggest it once boasted a global ocean in its distant past. Now, two new studies from NASA’s Dawn mission may reveal traces of an ancient ocean in the crust, with remnants left behind in the muddy mantle beneath.
Scientists used the tug of gravity on NASA’s Dawn spacecraft to track gravitational features across the dwarf planet Ceres. Combined with models of the evolution of the icy surfaces, these observations reveal an ocean mostly frozen into a strong but flexible crust, with a mud-rich inner layer that keeps things moving.
Referring to the new research, Dawn project scientist Julie Castillo-Rogez told Space.com, “The [new] papers modeled the relaxation of Ceres’ surface morphology at the global scale and the resulting gravitational anomalies in order to get several important results.” [Awesome Ceres Photos by NASA’s Dawn]
When Dawn arrived at Ceres in 2015, it found a mostly flat world with only a single mountain, Ahuna Mons, and craters that were smaller than anticipated and not very rich in geological features. Past researchers have hunted for an explanation for the mystery of the missing craters and the lack of mountains, and they have concluded that the planet’s crust must be slowly relaxing, like honey poured onto a plate.
But that research looked at only small parts of the planet. The new research examined the world on a larger scale, Castillo-Rogez said.
The first paper by Anton Ermakov, a researcher at NASA’s Jet Propulsion Laboratory, tracked small changes in Dawn’s orbit to determine what is going on beneath Ceres’ surface. As the spacecraft orbited the tiny world, Ceres pulled at it. More massive regions tugged more sharply on the spacecraft, while less dense regions had less of an impact. This affected how long it took the signal to travel from the orbiter to the…