- Ceres is a dwarf planet that orbits the sun between Mars and Jupiter in the asteroid belt. Ceres is the largest object in the asteroid belt.
- The dwarf planet is cold now, but new research paints a picture of Ceres hosting a deep, long-lived energy source.
- Data from NASA’s Dawn spacecraft show that Ceres might have maintained habitable conditions in the past.
NASA/JPL published this original story on August 20, 2025. Edits by EarthSky.
Could Ceres have been habitable?
NASA said this week that the dwarf planet Ceres – largest body in the asteroid belt between Mars and Jupiter – might once have had a lasting source of chemical energy. It might have had the oomph to fuel some microbial organisms. There’s no evidence for microorganisms on Ceres, now or in the past. But the finding supports theories that this intriguing little world might have once had conditions suitable for single-celled lifeforms.
The data come from NASA’s Dawn mission, which ended in 2018. It’s the mission that revealed the famous bright spots on Ceres (see image above), now known to be reflective regions made mostly of salts. These salts are thought to be left over from liquid that percolated up from underground. Scientists now believe Ceres had (or has) an enormous reservoir of brine, or salty water, below its surface.
And the Dawn mission also revealed evidence that Ceres has organic material in the form of carbon molecules. These are essential, though not sufficient on their own, to support microbial cells.
Still, scientists are pondering the question of life on this world. Keep reading to learn the latest on possible habitability for Ceres.
What’s needed for life on Ceres?
The presence of water and carbon molecules are two critical pieces of the habitability puzzle on Ceres. The new findings offer the 3rd: a long-lasting source of chemical energy in Ceres’ ancient past. This energy could have made it possible for microorganisms to survive. This result does not mean that Ceres had life. But, rather, it means there likely was “food” available should life have ever arisen on Ceres.
Science Advances published the peer-reviewed study on August 20, 2025. In the study, the authors built thermal and chemical models mimicking the temperature and composition of Ceres’ interior over time. They found that 2.5 billion years or so ago, Ceres’ subsurface ocean may have had a steady supply of hot water containing dissolved gases traveling up from metamorphosed rocks in the rocky core. The heat came from the decay of radioactive elements within the dwarf planet’s rocky interior that occurred when Ceres was young. That’s an internal process thought to be common in our solar system.
Sam Courville was lead author of the study and is now at Arizona State University. Courville said:
On Earth, when hot water from deep underground mixes with the ocean, the result is often a buffet for microbes: a feast of chemical energy. So it could have big implications if we could determine whether Ceres’ ocean had an influx of hydrothermal fluid in the past.
Catching chill
The Ceres we know today is unlikely to be habitable. It is cooler, with more ice and less water than in the past. There is currently insufficient heat from radioactive decay within Ceres to keep the water from freezing, and what liquid remains has become a concentrated brine.
The period when Ceres would most likely have been habitable was between 1/2 billion and 2 billion years after it formed (or about 2.5 billion to 4 billion years ago). That’s when its rocky core reached its peak temperature. Also, it’s when warm fluids would have been in Ceres’ underground water.
But the dwarf planet doesn’t have the benefit of present-day internal heating generated by the push and pull of orbiting a large planet, like Saturn’s moon Enceladus and Jupiter’s moon Europa do. So Ceres’ greatest potential for habitability-fueling energy was in the past.
This result has implications for water-rich objects throughout the outer solar system, too. Many of the other icy moons and dwarf planets that are of similar size to Ceres (about 585 miles, or 940 km, in diameter) and don’t have significant internal heating from the gravitational pull of planets could have also had a period of habitability in their past.
Bottom line: Could Ceres have been habitable? New research using data from NASA’s Dawn mission indicates it might have had the energy necessary to support some microbial metabolisms.
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