(ORDO NEWS) — The dwarf planet Ceres was once thought to be a rather primitive piece of rock. But just a few years ago, NASA’s Dawn space probe showed that there is more to this cosmic body than meets the eye.
Ceres is located in the asteroid belt between Mars and Jupiter, and at the same time is the largest asteroid in the solar system and the only dwarf planet closer than Neptune.
Ceres is an ocean world, according to a new analysis of Dawn data. Beneath the surface, there is brackish water that covers the entire dwarf planet.
The discovery sharpens the importance of sending a new mission to explore Ceres more closely to assess its potential habitability – and perhaps even look for signs of extraterrestrial life.
It all started in early 2015, even before the Dawn probe arrived in orbit around Ceres. The probe recorded strange, abnormally bright spots in Occator Crater on a dwarf planet, an impact crater 20 million years old.
Later, scientists found that these shiny spots are composed of sodium carbonate.
Here on Earth, sodium carbonate is found around hydrothermal vents in the deep ocean, where heat seeps into the water from cracks in the seabed. While away from the sunlight that powers photosynthesis, these vents are teeming with life, a food chain that relies on chemosynthetic bacteria that use chemical reactions rather than sunlight to generate energy.
But the source of Ceres’ sodium carbonate remained a matter of controversy. Was this due to subsurface ice that melted from the impact of an asteroid and then froze again? Or did liquid seep to the surface during the impact, suggesting that Ceres is hotter beneath the surface than we thought?
Well, according to a series of articles published in the journals of Nature, the answer to the last two questions seems to be an emphatic yes, with some compelling evidence.
The analyzed data was collected during the final phase of the Dawn mission. After depleting its fuel, the spacecraft descended to an altitude of just under 35 kilometers, collecting data with an impressive resolution: 10 times higher than during the main time of the mission, with particular attention to the Occator crater.
At this resolution, Dawn was able to register changes in gravity in the crater at the scale of the geological units in and around it. These changes in gravity, combined with thermal simulations, suggest density changes consistent with a deep reservoir of fluid below the crater.
This reservoir is created by the heat and cracks that resulted from the impact of the asteroid, forming the salt deposits that we see today.
Although the crater is about 20 million years old, there is evidence that the salts on its surface are much younger. High-resolution imagery shows that Ceres’ ice volcanoes may have been active only 2 million years ago.
And this is confirmed by an unexpected discovery – the presence of a rare mineral, hydrohalite. Spectrometry revealed this hydrated form of sodium chloride at the very top of the Cerealia Facula dome, the brightest spot in Occator Crater.
Contact us: [email protected]