Asteroid Bennu is revealing crucial insights into the origins of life as scientists analyze pristine samples collected by NASA’s Osiris-Rex spacecraft. Findings include essential minerals, amino acids, and carbon compounds, suggesting a diverse range of organic materials not found on Earth. This research supports theories of extraterrestrial influences on life’s emergence, while also highlighting the significance of water and mineral salts in Bennu’s parent body, which may have created conditions for biological molecule formation.
Asteroid Bennu Unveils Life’s Building Blocks
The asteroid Bennu is starting to share its mysteries as scientists analyze samples that have remained untouched by Earth’s environment. Recent studies have uncovered vital minerals and amino acids that are crucial for the emergence of life. In 2020, NASA’s Osiris-Rex spacecraft successfully collected 120 grams of regolith—a mix of dust and gravel—from Bennu, located approximately 300 million km from Earth. This precious material was carefully stored in a sealed capsule to prevent any contamination before its release in 2023.
Groundbreaking Discoveries from Bennu’s Samples
Initial analyses confirmed the presence of essential elements, including “water crystals and carbon,” both fundamental to life, much to the delight of NASA administrator Bill Nelson. However, the findings suggest that Bennu contains an even wider range of compounds than those found on our planet. According to a study published in Nature Astronomy, led by NASA astrobiologist Daniel Glavin and astrochemist Jason Dworkin, the diversity of organic materials in the samples is inconsistent with known terrestrial biology. Among these organic compounds are fourteen of the twenty amino acids necessary for protein synthesis in Earth’s organisms, as well as the five nucleotide bases that form DNA and RNA.
This groundbreaking discovery bolsters theories favoring an extraterrestrial influence on the origin of life on Earth, while also leaving room for the possibility of life emerging from the planet’s early oceans or atmosphere. The analysis also identified rare amino acids and thousands of nitrogenous compounds that are not found on Earth, leaving scientists to ponder their creation and origins. The second study published in Nature points toward the “parent” body of Bennu, suggesting that this asteroid, a collection of debris, was formed less than 65 million years ago from a larger body dating back to the early solar system, approximately 4.5 billion years ago.
Tim McCoy, curator of the mineral collection at the National Museum of Natural History, highlights that the raw ingredients for life were likely interacting in complex ways within Bennu’s parent body. The research, conducted by a team of international laboratories, also identifies mineral salts—critical inorganic compounds for life—never before detected in extraterrestrial samples. The presence of these salts is attributed to the evaporation of water pockets that Bennu’s parent asteroid once harbored.
Professor Yasuhito Sekine from the University of Tokyo emphasizes the significance of this water, which would have contained organic and inorganic compounds capable of undergoing reactions to form biological molecules essential for life. These reactions could have been triggered by the evaporation of interstitial water, leading to the creation of brines akin to the salt crusts found on Earth’s dried lakes. Notably, samples from Bennu include six minerals similar to those identified in California’s Searles Lake.
The meticulous preservation of these samples in a nitrogen atmosphere, which prevented moisture exposure to volatile compounds, has made these findings possible. The implications of this research are profound, as brines could have provided environments conducive to the evolution or survival of life within our solar system, similar to those detected on Saturn’s moon Enceladus or the dwarf planet Ceres. These locations are now considered prime targets for future space exploration missions, with experts like Sara Russell, a planetary sciences professor in London, commending the significant advancements in our understanding of asteroids like Bennu and their potential role in making Earth habitable.