Scientists Detect Traces of Life-Supporting Elements From NASA’s Samples of Asteroid Bennu
NASA’s first asteroid sample return mission has indicated that organic elements necessary for life may be more widespread in space than previously believed. The mission returned with bits of asteroid Bennu for researchers to analyze, stated Smithsonian Magazine. Examinations unveiled that the bits contained traces of ancient salt water. As per researchers, such presence has never been recorded in any other meteorite or asteroid sample collected by humans from space. Findings regarding these pieces from Bennu have been published in the journal Nature.
NASA’s OSIRIS-REx spacecraft spent seven years in space and dropped a capsule in the Utah Desert in September 2023 containing many of its collections. On opening the capsule researchers found about 120 grams of precious asteroid fragments. Astronomers noted that many of these fragments belonged to 4.5 billion years old Bennu. As per experts, Bennu can give insights regarding the solar system's early days. Researchers hope that findings from this asteroid will help them understand how organic materials came to Earth and lay the groundwork necessary for life to flourish.
Researchers expected the several typical elements they found inside the Bennu fragments like clays and iron oxides. "I actually saw the samples when they were first opened," co-lead author Tim McCoy, curator of meteorites at the National Museum of Natural History shared. "We had expectations they would have a lot of clays, carbonates, sulfides, and iron oxides—and we found all of those."
The presence that surprised them was sodium carbonates. Researchers were not expecting it but were ecstatic as it implied that Bennu's parent asteroid hosted pockets of liquid water. Experts speculated that after this water evaporated it left behind salty residues, rich in substances like phosphorous which can support life.
Experts think these residues may have broken apart and fallen on Earth as meteorites. Ultimately these remnants became the seeds of life on the planet. Researchers were delighted to garner such meaningful insights from the analysis. "We were super excited to find this—I’ve been studying meteorites for 35 years and had never seen this mineral before," McCoy added.
"That was really the breakthrough that told us we were looking at an ancient evaporite sequence." Experts believe such bits will help them to gain an understanding of how precursors of life existed in the asteroid. "Phosphates can help to make sugars. Clays can help to make things like nucleotides that build RNA and DNA," McCoy said. "Sodium brines are really essential to both ... speeding up those reactions and to help release those molecules after they form."
Another study focussed on Bennu fragments that came from NASA’s OSIRIS-REx spacecraft revealed the presence of amino acids and five main nucleobases incorporated in RNA and DNA. These findings back up the long-held speculation by experts that asteroids can transport organic molecules to various planets and stimulate life in them.
"The key mineralogical and chemical material needed for life’s emergence on Earth was being delivered to our planet early in its history," Michael Ackerson, a research geologist at the National Museum of Natural History said. "Effectively, Bennu’s brines created a nursery for the development of complex organic molecules that were subsequently delivered to a nascent Earth."