The dwarf planet Ceres, which is the biggest object located in the asteroid belt between Mars and Jupiter, is definitely a mysterious and strange world. For a long time it’s been believed that Ceres had a subsurface ocean at some point and that’s what NASA’s Dawn spacecraft was hopefully going to find out when it was launched back in 2007 to observe the dwarf planet. Although it was officially retired in 2018, Dawn certainly gathered some interesting data on the icy world.
While it was previously suggested that the ocean on Ceres would have froze a very long time ago, new analysis of odd features around recent craters indicate otherwise. Astronomers have been analyzing data for the past five years and they believe they have found evidence of large quantities of salty liquid on the surface of the dwarf planet. And based on its gravitational changes, a salt water reservoir stretching hundreds of miles and 25 miles deep may be present below the ice.
In an interview with Astronomy, Maria Cristina De Sanctis, who is from the National Institute of Astrophysics in Rome as well as a Dawn team member and a co-author of the study, explained, “Past research revealed that Ceres had a global ocean, an ocean that would have no reason to exist [still] and should have been frozen by now,” adding, “These latest discoveries have shown that part of this ocean could have survived and be present below the surface.” The fact that the water is so salty would explain why it would have remained in liquid form as salt lowers the freezing point.
If they can confirm that this liquid water still exists on Ceres, it would mean that salty, muddy liquid approximately the size of the Great Salt Lake in Utah (75 miles long by 28 miles wide) would cover the dwarf planet that’s only 590 miles across.
Julie Castillo-Rogez, who is a Dawn project scientist from NASA’s Jet Propulsion Laboratory (JPL), revealed, “Oceans should be common features of dwarf planets based on what New Horizons learned at Pluto and Dawn at Ceres.”
A salty ocean isn’t the only odd characteristic on Ceres as Dawn found a pair of shinning white spots inside two different craters (Occator Crater and Haulani Crater) that when the impact hit, it would have revealed the muddy salt water.
Scientists conducted extensive studies on the Occator Crater (seven studies have been published about the crater and can be read here) and they think that a chunk of space rock hit the dwarf planet around 20 million years ago that would have broke the icy crust, revealing the salty water underneath. It would have, however, frozen back over within several hours but it would have left the liquid water underneath the crater and may have erupted from the middle part of the crater – which would have caused the mysterious white spots – as recently as just two million years ago.
Additionally, the European Space Agency’s Herschel Telescope noticed water vapor rising from the same area which would suggest that there were eruptions of liquid salt water even more recently. “It’s really kind of a smoking gun, because you would have expected it had gone away if it had been sitting there even close to the surface for millions of years,” stated Carol Raymond who is the Dawn Principal Investigator at JPL and another co-author of the study.