For the first time, scientists discover water on asteroids through direct observations

NASA's flying observatory, SOFIA, mounted on a Boeing 747SP aircraft, was decommissioned a year and a half ago, but the data it collected is still contributing to scientific research. Using information gathered by its infrared telescope, a group of scientists has, for the first time, directly observed water on rocky asteroids within the Solar System. These findings will serve as a foundation for refining models of planetary system evolution and life on Earth.

Several years ago, when SOFIA regularly ascended to the stratosphere, one group of scientists used it to detect water molecules in a crater on the Moon's southern pole. According to measurements, there were 355 ml of water per cubic meter. The water was chemically bound to minerals, but its molecules were clearly visible in the mid-infrared spectrum. 

Building on this experience, researchers from the Southwest Research Institute in the U.S. decided to search for water on four rocky asteroids in the main belt between Mars and Jupiter: Iris, Parthenope, Melpomene, and Massalia. Water molecules were distinctly identified in the signals from Iris and Massalia, while the signals from Parthenope and Melpomene were drowned out by noise. 

Directly observing water on rocky asteroids suggests that water on planets and Earth could have originated from rocky asteroids, previously thought to be entirely devoid of water. These celestial bodies form closer to stars and were considered waterless, while more distant asteroids were expected to have enough preserved water ice to be relevant for the formation of watery conditions on planets. The data obtained through SOFIA indicates that rocky asteroids also played a role in providing water to planets.

Understanding the distribution of water in planetary systems will help us better comprehend the processes that create conditions for the emergence of life. These conditions are likely to be repeated in various stellar systems, guiding the search for extraterrestrial life in the most promising direction. Scientists are inspired by the results obtained with SOFIA and plan to leverage the capabilities of the Webb telescope to search for water on other rocky asteroids in our system.