The dwarf planet Ceres – long believed to be a barren space – is an ocean world with seawater reservoirs beneath it, the results of a major exploration mission showed on Monday.
Ceres is the largest object in the asteroid belt between Mars and Jupiter and has its own gravity, enabling the NASA Dawn spacecraft to capture high-resolution images on its surface.
Today a team of scientists from the United States and Europe analyzes images that have been removed from the orbiter, obtained around 35 kilometers (22 miles) from the asteroid.
They focused on Occator’s 20-million-year-old crater and determined that there was a “vast reservoir” of brine beneath it.
Numerous studies published Monday in the journals Nature Astronomy, Nature Geoscience and Nature Communications also shed additional light on the dwarf planet, discovered by Italian polymath Giuseppe Piazzi in 1801.
Using infrared imaging, a team discovered the presence of the compound hydrohalite – a material common in sea ice but has so far not been detected on Earth.
Maria Cristina De Sanctis, from the National Institute of Astrophysics of Rome says hydrohalite is a clear Ceres’ sign used to have sea water.
“We can now say that Ceres is a kind of ocean world, like some of the moons of Saturn and Jupiter,” he told AFP.
The team says salt deposits seem to have built up over the last two million years – a twinkle in an hour in space.
This indicates that brine could still ascend from the interior of the planet, something De Sanctis said could have profound implications for future studies.
“The material found in Ceres is very important in terms of astrobiology,” he said.
“We know these minerals are paramount for the emergence of life.”
Writing in an accompanying comment article, Julie Castillo-Rogez, from the Jet Propulsion Laboratory of the California Institute of Technology, said the discovery of hydrohalite was a “smoking gun” for continuous water activity.
“That material is not stable on Ceres’ surface, and therefore should be released recently, ”he said.
In a separate paper, US-based researchers examined images of the Occitor crater and found that its mounds and hills could have formed when the water was moved by the impact of a meteor froze on the surface.
The authors say that their findings show that such water-freezing processes “transcend Earth and Mars, and have been active in Ceres in the geological past recently”.
pg / klm / dl