Context:
Recently, NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) collected samples from asteroid Bennu.
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- Bennu samples contained the highest concentration of life-supporting extraterrestrial compounds ever brought to Earth.
- Unlike meteorites, these samples remained unaltered, protected in a sealed canister, and shielded from heat generated due to entering the earth’s atmosphere.
- The samples were analyzed in a controlled inert gas, in a contamination-free lab.
Key findings of the exploration
Amino Acids: 14 of the 20 amino acids used by life on Earth were found in the Bennu samples.
- Amino acids are essential for forming proteins, which are key to life.
Presence of Nucleobases: All 5 nucleobases (adenine, thymine, guanine, cytosine, uracil), essential for DNA and RNA, were detected in Bennu samples.
- Nucleobases store and transmit genetic information, vital for life.
Ammonia & Formaldehyde: High levels of ammonia, which reacts with formaldehyde to form amino acids, were found.
- This supports the idea that basic molecules for life could form in space.
Amino Acid Chirality: Both left- and right-handed amino acids were found in equal amounts.
- On Earth, life uses only left-handed amino acids, raising questions about why this preference exists.
Ancient Saltwater Evidence: Bennu’s samples showed 11 minerals like calcite, halite, and sylvite, formed when salt water evaporates.
- This indicates Bennu may have had water, a crucial ingredient for life.
Environment: Minerals such as trona (first time found in extraterrestrial samples) suggest Bennu had an environment that could support life-related chemistry.
Life on another planet: The discovery of life’s building blocks on Bennu suggests that similar conditions may exist on other planets or moons, increasing the possibility of life elsewhere in the solar system.