Analysis of samples returned from asteroid Bennu by NASA's OSIRIS-REx mission has uncovered a significant abundance of organic compounds and minerals, substantially enhancing our understanding of life's origins. These meticulously collected samples, delivered to Earth in September 2023, contain 14 of the 20 amino acids essential for life on our planet, along with all five nucleobases fundamental to DNA and RNA.
This discovery strongly suggests that asteroids like Bennu may have played a crucial role in seeding early Earth with the necessary components for life to emerge. The presence of water-soluble phosphates within the Bennu samples provides compelling evidence that Bennu's parent body likely possessed liquid water in its past. Such an environment would have been conducive to prebiotic chemistry, the complex reactions thought to precede the emergence of life.
Further insights from the James Webb Space Telescope indicate a potential shared origin for asteroids Bennu and Ryugu, suggesting they may have fragmented from a single, massive parent asteroid billions of years ago. This connection is supported by spectral similarities observed between Bennu, Ryugu, and the larger asteroid 142 Polana, offering a unique window into the processes of asteroid family formation and dispersal across the solar system.
The discovery of these life-essential molecules in pristine, extraterrestrial samples underscores the potential for life's ingredients to be widespread throughout the cosmos. The OSIRIS-REx mission's success in collecting and returning these samples highlights the invaluable role of sample return missions in unraveling the mysteries of the early solar system and the potential for life beyond Earth. The presence of both left- and right-handed amino acids in equal measure within the Bennu samples also raises intriguing questions about the early chemical environment on Earth and the subsequent development of life's specific chirality.