Did an ancient asteroid deliver the essential ingredients for life to Earth?
NASA's OSIRIS-REx mission recently returned a cache of dust and rocks from the asteroid Bennu. These pristine samples are now revealing unexpected biological building blocks, including sugars and a mysterious, ancient substance that has never been seen in space rocks before.
The OSIRIS-REx mission, which launched on September 8, 2016, successfully collected surface material from the near-Earth asteroid Bennu on October 20, 2020 [S2:p2]. After a long journey, the spacecraft released a capsule that parachuted into Utah's West Desert on September 24, 2023 [S2:p2]. The material was then transported to NASA’s Johnson Space Center, where it is being curated for decades of global scientific study [S3:p2].
Recent analyses published in journals such as Nature Geoscience and Nature Astronomy have uncovered remarkable chemical signatures [S4:p2]. Researchers led by Yoshihiro Furukawa of Tohoku University identified the five-carbon sugar ribose and the six-carbon sugar glucose within the samples [S4:p3]. While these are not direct evidence of life, their presence alongside previously detected amino acids and nucleobases suggests that the fundamental building blocks of biological molecules were widespread throughout the early solar system [S4:p3].
The discovery of ribose is particularly significant because it supports the 'RNA world' hypothesis, suggesting that early life may have relied on RNA as a primary molecule for information storage [S4:p5]. Interestingly, while ribose was found, researchers did not find deoxyribose in the samples [S4:p5]. Additionally, a team led by Scott Sandford and Zack Gainsforth identified a previously unknown, nitrogen- and oxygen-rich 'space gum' [S4:p7]. This ancient, polymer-like material likely formed as Bennu's parent asteroid warmed during the solar system's infancy [S4:p7].
