The mystery behind the bright areas on the surface of the planet Ceres is no longer going to bother the NASA scientists and the whole science enthusiasts. The Dawn mission which ended in October 2018 came up with some extraordinary findings. The Ceres is a dwarf planet, present in the asteroid belt between Mars and Jupiter.
The data obtained from the Dawn mission found that the bright areas on the Ceres are composed of sodium carbonate and the latest studies on the data revealed that this compound is formed out of the water that is present in Ceres that seeped to the surface and evaporated quickly making it a highly reflective salt crust. The source of the water is found to be a deep reservoir of highly salty water which is 25 miles i.e., 40 km deep and hundreds of miles wide.
The new studies on the region which has the extensive bright areas, the Occator Crater revealed that the Ceres is a water-rich body like many other icy bodies even though it doesn’t benefit from the internal heating that is caused by the gravitational interaction of large planets.
These findings also shed light on the geological activity happening in the Occator Crater.
Story of the bright areas on Ceres
The story of the bright areas on Ceres begins when it was first observed through telescopes by the scientists. But the nature of the material it is composed of was unknown. Then in 2015, the Dawn spacecraft started its mission to end all the mysteries about Ceres. The cameras on Dawn captured two prominent bright areas on the Occator Crater which were named Cerealia Facula and Vinalia Faculae. (“Faculae” means bright areas).
The brightness of these areas is a direct indicator of their age. As time passes, due to interactions and collisions with micrometeorites, the brightness of these areas decreases. But the brightness of the bright areas on the Occator Crater shows that these are very recently formed. Some are formed even less than 2 million years ago. Another important conclusion from these studies was that the geologic activity which results in these areas could be ongoing.
On the surface of Ceres the water containing salts quickly dry up within a hundred years. But the current studies show that Ceres still have water which means that the water has reached the surface very recently. This is evidence for the presence of water under the Occator Crater and also for the ongoing geologic activity.
Other unusual findings
The geologic activity in Ceres is similar to that happens in icy moons of our solar system. This shows that ice-rich bodies which are not moons could be also active. The conical hills reminiscent to earth’s pingos are present in Ceres which is also an evidence to the presence of liquid on the Occator Crater. Pingos are small ice mountains found in polar regions of earth formed by frozen pressurised water. This was the first time such a structure was observed on a dwarf planet.
The density of Ceres’ crust as a function of depth was identified and it is found to increase significantly with depth. The dawn spacecraft is the only one to orbit two extraterrestrial destinations – Ceres and the giant asteroid Vesta because of the efficient ion propulsion system. Now Dawn is placed in a longer duration orbit which will prevent it from colliding to the dwarf planet, Ceres for decades.
Reference: NASA
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