NASA’s Dawn mission revealed Ceres as an ocean world, transforming our understanding of this dwarf planet as a lifeless space rock.
TL;DR
NASA’s Dawn mission has confirmed that Ceres, once thought to be a barren space rock, is actually an ocean world. Scientists have identified a massive underground reservoir of saltwater beneath the surface of the dwarf planet, particularly under the Occator crater. This discovery includes the presence of hydrohalite, a material found in sea ice on Earth, which has never before been detected beyond our planet. Researchers believe these salt deposits formed relatively recently, suggesting that water is still active on Ceres. These findings could have significant implications for the search for life in our solar system.
____________________________
Once thought to be a lifeless space rock, the dwarf planet Ceres has been revealed as an ocean world with significant reservoirs of seawater beneath its surface, according to findings from a major exploration mission announced on Monday.
Ceres, the largest object in the asteroid belt between Mars and Jupiter, is massive enough to be shaped by its gravity, allowing NASA’s Dawn spacecraft to capture detailed images of its terrain.
A team of US and European scientists studied these images, taken from just 35 kilometers (22 miles) above the surface, with a focus on the 20-million-year-old Occator crater. Their analysis revealed a vast underground reservoir of brine.
Published in prestigious journals such as Nature Astronomy, Nature Geoscience, and Nature Communications, these studies also provided new insights into Ceres, first discovered by Italian polymath Giuseppe Piazzi in 1801.
Using infrared imaging, one team identified hydrohalite—a substance commonly found in sea ice on Earth, but never before seen beyond our planet.
Maria Cristina De Sanctis from Rome’s Istituto Nazionale di Astrofisica explained that hydrohalite confirms Ceres once had a significant body of seawater.
“We can now categorize Ceres as an ocean world, akin to some of Saturn and Jupiter’s moons,” she shared with AFP.
Researchers believe the salt deposits on Ceres are relatively young, possibly formed within the last 2 million years—a mere blink in cosmic terms—hinting that brine may still be seeping to the surface. De Sanctis emphasized the potential significance of this discovery for future research.
“The minerals found on Ceres are vital to the origin of life,” she stated.
In a related commentary, Julie Castillo-Rogez from NASA’s Jet Propulsion Laboratory called the hydrohalite discovery a “smoking gun” for ongoing water activity.
“That substance is unstable on Ceres’ surface, which means it must have appeared very recently,” Castillo-Rogez added.
Meanwhile, US-based researchers used images of the Occator crater to propose that its unique terrain—composed of mounds and hills—may have formed when water expelled by a meteor impact froze on the surface. Their research suggests that similar processes involving frozen water could extend beyond Earth and Mars and have taken place on Ceres in its recent geological history.