Scientists analysing samples from asteroid Bennu, delivered to Earth by NASA's OSIRIS-REx mission , have revealed new findings about the origins of life and the early days of our solar system.
The asteroid material, delivered in September 2023, contains an abundance of organic molecules, salts, and minerals, some of which have never been observed in meteorites that have fallen to Earth.
The findings, published today in two papers in Nature and Nature Astronomy, suggest that Bennu originated from an ancient wet world, possibly from the icy regions beyond Saturn.
These discoveries shed new light on how the building blocks of life, such as water and essential chemicals, could have been delivered to Earth-and possibly other planets-by asteroids billions of years ago.
The University of Manchester received part of the sample from asteroid Bennu to support the international analysis effort. In this latest piece of research, Rhian Jones, Professor of Cosmochemistry at The University of Manchester, played a key role in examining the mineralogy of the samples and interpretation of the data.
Professor Jones said: "This research is like opening a time capsule from the early solar system. We were surprised to find that the asteroid sample held such a complete library of minerals and some unique salts.
"The salt minerals discovered in the sample are similar to those in dried-up salty lakes on Earth. We think that these briny conditions played a key role in how water and the ingredients for life might have been delivered to our planet billions of years ago. There is evidence for similar brines on Saturn's moon Enceladus and the dwarf planet Ceres. "
In the Nature Astronomy paper, scientists report that they have discovered some key ingredients for life, including 14 of the 20 amino acids that living organisms use to build proteins and all five nucleobases that form DNA and RNA. They also found high levels of ammonia, a potential precursor for these compounds.
Unlike meteorites that fall to Earth and are altered by the atmosphere, Bennu's sample was carefully preserved during its journey, with the team protecting every pebble and speck of the Bennu sample while maintaining its pristine quality. As a result, the asteroid sample is giving scientists around the world a rare glimpse at our solar system's earliest days, without having to separate or account for changes caused by exposure to Earth's atmosphere.
Professor Jones said: "Some of the salts we have found in Bennu have never been seen in meteorites that have fallen to Earth. This is likely because these substances were broken down by exposure to Earth's environment. Meteorites similar to the Bennu material are also very rare because they do not easily survive their journey through the Earth's atmosphere."
The new results are the culmination of years of international collaboration involving scientists from NASA, the Smithsonian, London's Natural History Museum and Universities across the world.
Professor Jones added: "These results were only possible because of the extremely careful curation of the Bennu sample from the moment the capsule landed. It's a testament to what we can achieve with international collaboration and cutting-edge technology."
The research marks the first in-depth analysis of Bennu's organics and minerals and more scientific results from the OSIRIS-REx team are due in the coming months.
NASA has also stored 70% of the sample at Johnson Space Center's curation lab for study by the broader research community, including by scientists who have yet to be born and who will study it with instruments that do not exist today.
NASA's Goddard Space Flight Center in Greenbelt, Maryland, provided overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator. The University leads the science team and the mission's science observation planning and data processing. Lockheed Martin Space in Littleton, Colorado, built the spacecraft and provided flight operations.
