Life's building blocks may have originated in space—Bennu sample suggests
What's the story
NASA scientists have made an interesting discovery in the sample from the Bennu asteroid, which the agency returned to Earth in 2023. The team found molecules essential for life, including amino acids and evidence of an ancient environment that could have sparked life's chemistry. The findings were revealed in a NASA press release and detailed in research papers published in Nature and Nature Astronomy journals.
Life's emergence
Implications for extraterrestrial life and Earth's origins
While the findings do not confirm the existence of extraterrestrial life, they do show that the conditions required for life to emerge were common in the early solar system. This supports theories that amino acids required for life on Earth may have originated elsewhere, increasing the chances of life emerging on other planets. The Bennu asteroid sample contained 14 of the 20 amino acids used by Earth-based organisms to create proteins. Ammonia and formaldehyde was also discovered in the sample.
Mineral discovery
Rare salt minerals found in Bennu's dust particles
The scientists also found tiny crystals of rare salt minerals called halite and sylvite within Bennu's dust particles. These findings indicate a history of saltwater on the larger 4.5 billion-year-old asteroid from which Bennu came. The presence of these minerals provides new insights into water activity during the earliest times in our Solar System. They are important for the formation of organic compounds such as nucleobases and nucleosides — the prebiotic building blocks of terrestrial biology.
Ongoing research
Bennu sample analysis may shed light on distant icy bodies
The Bennu sample also had a range of other salt minerals such as sodium carbonates, phosphates, sulfates, and fluorides. These findings could give researchers clues about what goes on on far-off icy bodies in our Solar System like Saturn's moon Enceladus and the dwarf planet Ceres in the asteroid belt between Mars and Jupiter. Both Enceladus and Ceres have subsurface brine oceans, which makes them potential hosts for life.
Scenario
How NASA's asteroid mission brought Bennu's secrets to Earth
NASA launched the OSIRIS-REx spacecraft on September 8, 2016, and it reached the near-Earth asteroid Bennu on December 3, 2018. After nearly two years of study, it collected a sample during a touchdown on October 20, 2020. The sample was then sealed in a protective capsule and returned to Earth, where it was successfully retrieved on September 24, 2023.