NASA's OSIRIS-REx mission has made groundbreaking strides by confirming the presence of key chemical building blocks of life from samples collected from the asteroid Bennu. This lends significant credibility to the long-held theory of extraterrestrial materials contributing to the development of life on Earth.
Launched to explore the near-Earth asteroid Bennu, the OSIRIS-REx spacecraft returned to Earth with samples on September 24, 2023. This robotic mission, which began collecting data and samples in 2020, has provided some of the best evidence to date indicating how asteroids may have seeded early Earth with the fundamental ingredients for life. Scientists have now analyzed the rocks and dust and found results published in two specialized journals — Nature Astronomy and Nature.
The findings revealed the presence of 14 of the 20 known amino acids, the organic compounds used to construct proteins, and all five nucleobases, which are the genetic components of DNA and RNA. Astrobiologist Danny Glavin from NASA's Goddard Space Flight Center emphasized the import of these findings, stating, "The detection of these key building blocks of life... increases the chances life could have started beyond Earth.”
These results not only bolster the theory of life’s origins on Earth stemming from external sources but also suggest the conditions necessary for organic chemistry were present on Bennu's parent body. This celestial body formed around 4.5 billion years ago and appears to have been destroyed about 1-2 billion years ago before fragments coalesced to form the asteroid Bennu.
The scientists were particularly interested in the mineral composition of the samples, finding they were influenced by environments where salty liquids had evaporated, creating brines. Tim McCoy, curator of meteorites at the Smithsonian Institution, noted, "The brines provide an environment in which elements and simple organics could have combined to form more complex prebiotic organics on the pathway to life." Such environments could have enabled the formation of life’s building blocks similar to those found on Earth.
While these findings lend weight to the idea of life’s prebiotic ingredients coming from space, NASA has clarified they do not indicate the existence of actual extraterrestrial life. The signature compounds identified could very well have been integral to processes leading to life, underlining the conditions present on other celestial bodies.
Accordingly, the research adds to existing knowledge; similar organic compounds have been identified previously in meteorites without being able to definitively rule out ground contamination. Receiving pristine samples directly from Bennett allows for unprecedented confidence. Glavin shared, "We can trust these results." This purity of data gives scientists newfound reassurance as they explore life's origins.
Researchers are cautious, highlighting the complexity of moving from simple amino acids and nucleobases to actual living organisms. Jason Dworkin adds, "The suite of simple protein amino acids and nucleobases found... are a long way from anything living, as they are much simpler than the complex systems seen within cellular life." The astronomical connection to how life on Earth began remains speculative yet tantalizing, inviting future missions to investigate similar celestial bodies.
Despite the distant links drawn, the OSIRIS-REx findings open new discussions about whether life could exist elsewhere, underlining the importance of continued exploration beyond our planet. The pursuit of discovering extraterrestrial life, once thought to be bound to worlds far away, is now within reach with earthly insights combined with extraterrestrial samples.
Encouragingly, as NASA prepares for future missions, the knowledge gained from Bennu strengthens our grasp on cosmic biology, propelling new scientific inquiries. The question is, will similar research lead to the discovery of life outside Earth? With the compelling nature of Bennu's fingerprints on life's ingredients, scientists are more eager than ever to investigate.
OSIRIS-REx's successful mission demonstrates the endless possibilities inherent within space exploration, hinting at how the universe may have facilitated the origins of life closer to home than once thought. Each rock and dust grain serves as proof; they are more than remnants of cosmic happenings. They are potential keys to answering one of humanity's greatest questions: how did we come to be?