Samples collected from the asteroid Bennu by NASA’s OSIRIS-REx spacecraft have provided evidence of material that predates the formation of the solar system, scientists said this week. The findings suggest asteroids like Bennu may have carried essential building blocks of life to Earth billions of years ago.
OSIRIS-REx, launched in 2016, gathered surface samples from Bennu in October 2020 before returning them to Earth in 2023. Three independent research groups have now analyzed the material. “We found stardust grains with compositions that predate the solar system, organic matter that likely formed in interstellar space, and high temperature minerals that formed closer to the Sun,” said Ann Nguyen, a co-lead author of the studies.
One team traced Bennu’s origins to a larger parent body, suggesting it accumulated ice and dust in the early solar system. As the ice melted, water interacted with surrounding minerals, altering their composition. The findings support theories that asteroids may have delivered water to early Earth during planetary formation.
Another group found signs of impact melts, indicating Bennu’s surface has been repeatedly struck by micrometeorites and shaped by solar wind at a faster rate than expected. The results highlight how small bodies continue to evolve under constant bombardment in space.
With its mission complete at Bennu, OSIRIS-REx has been renamed OSIRIS-APEX and is now en route to asteroid Apophis, where it will conduct further studies after the asteroid’s close approach to Earth in 2029. Scientists hope these missions will deepen understanding of how the solar system formed around 4.5 billion years ago.