Ceres, once thought to be dry, hides a vast underground ocean beneath its cratered surface.
Key Takeaways:
- Scientists have confirmed that Ceres is an ocean world with reservoirs of salty water beneath its surface.
- The discovery was made using high-resolution images from NASA’s Dawn spacecraft, orbiting just 35 km above Ceres.
- Infrared imaging revealed hydrohalite, a sea ice compound never seen outside Earth, indicating past ocean activity.
- Evidence suggests the briny deposits formed within the last 2 million years and may still be active today.
- These findings have major astrobiological implications, as the minerals detected are crucial for life’s emergence.
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The dwarf planet Ceres, long considered a dry space rock, has been revealed as an ocean world with reservoirs of salty water beneath its surface, according to new research. Scientists analyzing data from NASA’s Dawn spacecraft confirmed that briny water still exists below the planet’s surface, potentially making it a target for future astrobiological studies.
Water Beneath the Surface
Ceres is the largest object in the asteroid belt between Mars and Jupiter and was first discovered by Italian astronomer Giuseppe Piazzi in 1801. NASA’s Dawn spacecraft, which orbited Ceres from 2015 to 2018, captured high-resolution images of its surface, particularly focusing on the 20-million-year-old Occator crater. A team of researchers from the U.S. and Europe analyzed these images, taken from just 35 km (22 miles) above the planet’s surface, and found strong evidence of an underground ocean.
Infrared imaging revealed the presence of hydrohalite, a substance commonly found in Earth’s sea ice but never before detected beyond our planet. Maria Cristina De Sanctis, a researcher at Italy’s Istituto Nazionale di Astrofisica, stated that the presence of hydrohalite confirms Ceres once had liquid seawater. The salt deposits in Occator crater appear to have formed within the last 2 million years, suggesting that the brine is still seeping up from below the surface.
Implications for Astrobiology
The discovery of ongoing water activity on Ceres has significant implications for the search for extraterrestrial life. Julie Castillo-Rogez from NASA’s Jet Propulsion Laboratory called the presence of hydrohalite a “smoking gun” for recent water movement. Since hydrohalite is unstable on Ceres’ surface, its existence indicates that the material must have emerged recently.
In a separate study, scientists found that the mounds and hills within Occator crater likely formed when water, ejected by a meteor impact, froze on the surface. This suggests that water-driven geological processes are not limited to Earth and Mars but have been active on Ceres in the recent past.
These findings, published in Nature Astronomy, Nature Geoscience, and Nature Communications, confirm that Ceres is an ocean world like some of Jupiter’s and Saturn’s moons. With essential minerals for life detected, Ceres may become a key target for future missions searching for signs of life beyond Earth.
