NASA’s Dawn mission has been studying the asteroid belt between Mars and Jupiter for 11 years and dramatically changed perceptions of the dwarf planet Ceres,media reported. The latest analysis of the data collected later in the mission provides some compelling answers to long-standing questions about the composition of Ceres, starting with the presence of a 25-mile-deep salt reservoir beneath ceres.
Over the past few years, scientists have been piecing together the mystery of the special geological activities of Ceres as data from the Dawn mission has been circulating back. The nature of its unusually bright spots in the Occator crater constitutes a mystery, and scientists are trying to understand how it formed and what it might represent.
There is evidence that these deposits are formed by salty liquids that bubble up to the earth’s surface to leave highly reflective sediments on the earth’s crust, but where does this liquid come from? While it is thought that underwater salt water storage is highly likely, the discovery of new evidence now led scientists to conclude that not only is it true, but that continuous geological activity keeps these salty surfaces fresh and bright.
The environment on ceres is an environment in which salt marshes, which store water, dehydrate after centuries. But the team found that the salt compounds were concentrated on a more well-known bright spot, the Cerealia Spot, which still carries water, suggesting that they must have only recently reached the surface. Carola Raymond, lead researcher on the Dawn mission, said the process dates back millions of years to the impact of a crater.
“For the large amount of sediment in the Cerealia spot, most of the salt comes from a muddy area beneath the surface about 20 million years ago, which was melted by the impact heat that formed craters,” she explains. Millions of years later, the heat generated by the impact subsides; however, the impact also creates large cracks that may reach deep, long-lived reservoirs that allow salt water to continue to penetrate the surface. “
In addition, the researchers found small hills on Ceres that resemble dating back to the Earth’s ice-water-water editing, further supporting the idea that there is liquid on the planet. Scientists have previously discovered this phenomenon on Mars, but never on a dwarf planet.
The team also used the latest data from Dawn to measure ceres in new gravity, and found that Ceres’ saltwater reservoir was about 25 miles (40 kilometers) deep and hundreds of miles wide. These gravity measurements also provide new insights into the dwarf planet’s interior — its crustal density increases with depth. This increase in density is much larger than the pressure alone, so the team believes this is the result of the underground reservoir incorporating salt and mud into the lower crust when it freezes.