NASA’s OSIRIS-REx mission has provided groundbreaking insights into the early solar system and the potential origins of life. The analysis of rock and dust samples from asteroid Bennu, delivered to Earth in 2023, has revealed the presence of key molecules associated with life on our planet.
The samples contain a mixture of organic compounds, including amino acids and nucleobases, which are fundamental to life as we know it. Specifically, 14 of the 20 amino acids used by life on Earth to create proteins were detected, along with all five nucleobases used in DNA and RNA. These findings suggest that the conditions necessary for life’s emergence may have been widespread in the early solar system.
Researchers also identified high concentrations of ammonia in the Bennu samples. Ammonia is significant in biology due to its potential to react with formaldehyde, also detected in the samples, to form complex molecules such as amino acids under suitable conditions.
The pristine nature of the space-collected sample has allowed scientists to identify these building blocks of life with unprecedented clarity. This supports the hypothesis that objects formed far from the Sun could have been crucial sources of raw materials for life throughout the solar system.
In addition to organic compounds, scientists discovered evidence of an ancient aqueous environment within the Bennu samples. Traces of 11 minerals, including calcite, halite, and sylvite, were identified. These minerals form as water containing dissolved salts evaporates over extended periods. This finding suggests the presence of a saltwater “broth” that could have facilitated the interaction and combination of organic compounds.
The complete set of evaporite minerals preserved in the Bennu sample provides insight into an evaporation process that may have lasted thousands of years or more. Some minerals, such as trona, were discovered for the first time in extraterrestrial samples.
While these discoveries do not provide direct evidence of life, they indicate that the ingredients and conditions necessary for life were present in the early solar system. This increases the possibility that life could have formed on other planets and moons.
The Bennu sample analysis also raises new questions. For instance, the amino acids found in the sample exist in equal mixtures of left-handed and right-handed versions, unlike life on Earth which predominantly uses left-handed amino acids. The reason for this “left-handed” preference in terrestrial life remains unknown.
The OSIRIS-REx mission, managed by NASA Goddard Space Flight Center, involved collaboration with the University of Arizona, Lockheed Martin Space, and international partners including the Canadian Space Agency and Japan Aerospace Exploration Agency. The mission’s findings contribute significantly to our understanding of the solar system’s potential for harboring life and the processes that may have led to life on Earth.
