The enigma of liquid water on the surface of stars without an atmosphere

For some time now, the scientific community has been puzzled by the presence of mysterious traces of liquid flows on the surfaces of celestial bodies without an atmosphere, such as the asteroids Vesta and Ceres, where physics tells us that water cannot exist in a liquid state.

A team including, among others, Jennifer Scully, from NASA’s Jet Propulsion Laboratory (JPL), and Michael J. Poston, from the Southwest Research Institute (SwRI) in the United States, has carried out a study in an attempt to clarify that mystery.

The authors of the new study have determined how the conditions created at a point on the surface of a star such as those mentioned due to the impact of a meteorite could produce masses of salt water that temporarily flow across the surface long enough to excavate ravines like this. enough to deposit sediments forming alluvial fans.

The team reproduced the pressures experienced by the ice of Vesta, one of the largest asteroids in our solar system, after the impact of a meteorite and the time it takes for the liquid released from the subsoil to refreeze.

The team modified a JPL test chamber to rapidly decrease the pressure on a liquid sample to simulate the drastic pressure drop that occurs when the temporary atmosphere created after an impact on an atmosphereless body like Vesta dissipates. In the experiments, the pressure drop was so rapid that the test liquids expanded immediately and dramatically, even expelling material from the sample containers.

This image of the Cornelia crater on Vesta shows features (highlighted on the left by the short white arrows) that, judging by the results of the new study, must have been formed by the action of salt water, which remained in a liquid state for as long as possible. quite long after the impact of a meteorite that excavated a crater and heated that area. (Images: NASA Jet Propulsion Laboratory)

Through these simulated impacts, the researchers found that pure water froze too quickly in a vacuum to make significant changes to its environment, but that salt-water mixtures remained liquid and flowing for at least an hour. This is enough for salt water to destabilize the slopes of crater walls in rock bodies, cause erosion and landslides, and potentially form other peculiar geological features.

The study is titled “Experimental Examination of Brine and Water Lifetimes after Impact on Airless Worlds.” And it has been published in the academic journal The Planetary Science Journal. (Fountain: NCYT by Amazings)