Almost five years ago, scientists have noticed two bright spots on the surface of Ceres, the largest object in our main asteroid belt. This peculiar finding via the Dawn spacecraft—which came as close 22 miles from Ceres’ surface—was further analyzed by NASA until the mission ended in 2018. The research, published last Monday on the Nature Astronomy journal, concluded that within the dwarf planet is a subsurface ocean reservoir of salt-enriched water.
“Scientists had figured out that the bright areas were deposits made mostly of sodium carbonate…They likely came from liquid that percolated up to the surface and evaporated, leaving behind a highly reflective salt crust,” NASA writes on their official website. “By analyzing data collected near the end of the mission, Dawn scientists have concluded that the liquid came from a deep reservoir of brine, or salt-enriched water.”
Furthermore, NASA notes that these bright regions, named Cerealia Facula and Vinalia Faculae, on Ceres are still young at roughly less than two million years old. Which means that the "geologic activity driving these deposits could be ongoing."
According to the space agency, this groundbreaking secret ocean hidden beneath Ceres could be about 25 miles deep and hundreds of miles wide. As per Dawn’s Principal Investigator Carol Raymond, the recent discovery has elevated the dwarf planet into “ocean world” status. "In the case of Ceres, we know the liquid reservoir is regional scale but we cannot tell for sure that it is global. However, what matters most is that there is liquid on a large scale,” she elaborates.
What’s more, NASA’s findings raises the question of whether extraterrestrial life could be possible or present on Ceres. While other ocean-rich bodies beyond Earth have been discovered before, including Pluto, Jupiter's moon Europa, Saturn's moon Enceladus, and Neptune's moon Triton, Ceres has proven to be the nearest entity for a possible landing investigation. “Ceres is a lot closer and it's a lot easier to get to than these moons in the outer solar system," Raymond explains of the dwarf planet located between the orbits of Mars and Jupiter. "So it is a very enticing target."
In fact, Dawn project scientist Julie Castillo-Rogez has reportedly already formally submitted a study that looks into a $1 billion mission that would land on Ceres. Astronomy.com notes that should NASA approve and fund the mission, it would likely take place sometime before 2032.
For more information read NASA’s blog post on Ceres here.