NASA finds key ingredients for life on asteroid, sparking debate about alien origins

NASA's Osiris-Rex spacecraft brought rock samples from the near-Earth asteroid Bennu. Now, in the analysis of the rock, scientists have found building blocks essential for life.

NASA's recent retrieval of asteroid samples has unveiled not only the pristine building blocks essential for life but also the salty remnants of an ancient water world, scientists reported on Wednesday. These discoveries present compelling evidence that asteroids may have sown the seeds of life on Earth, hinting that these vital ingredients were interacting with water almost from the very beginning.

"That's the kind of environment that could have been essential to the steps that lead from elements to life0," stated Tim McCoy of the Smithsonian Institution, who co-authored the study. 

The samples, collected by NASA's Osiris-Rex spacecraft, included 122 grams of dust and pebbles from the near-Earth asteroid Bennu. The spacecraft successfully delivered the sample canister to the Utah desert in 2023 before heading off to explore another space rock. This mission marks the largest cosmic collection from beyond the Moon, dwarfing previous asteroid sample missions by Japan that returned significantly smaller amounts.

Research teams have been analyzing small quantities of Bennu's valuable black grains—leftovers from the solar system's formation 4.5 billion years ago. The findings, published in the journals Nature and Nature Astronomy, revealed sodium-rich minerals, as well as amino acids, ammonia (a nitrogen compound), and even components of the genetic code.

Many of the fragile salts extracted from Bennu—akin to those found in the dry lakebeds of California's Mojave Desert and Africa's Sahara—would likely be lost if they were found in meteorites hitting Earth. "This discovery was only possible by analysing samples that were collected directly from the asteroid then carefully preserved back on Earth," explained Yasuhito Sekine from the Institute of Science in Tokyo, who was not involved in the studies.

Combining life's essential ingredients with sodium-rich saltwater or brines provides a clear pathway to the origin of life, according to McCoy, who serves as the curator of meteorites at the National Museum of Natural History. "These processes probably occurred much earlier and were much more widespread than we had thought before."

Daniel Glavin from NASA noted that one of the most unexpected findings was the notable abundance of nitrogen, including ammonia. While similar organic molecules have been detected in other meteorites, Glavin emphasized that those from Bennu are genuine—"real extraterrestrial organic material formed in space and not a result of contamination from Earth."

Bennu itself, a rubble pile measuring just a third of a mile (or half a kilometer) across, was once part of a larger asteroid that suffered collisions with other celestial bodies. The latest findings suggest that this parent body had an extensive underground network of lakes or even oceans, which eventually evaporated, leaving behind crucial salty evidence.

Currently, sixty labs worldwide are analysing bits of Bennu as part of initial studies, according to Dante Lauretta, the chief scientist of the mission. The majority of the USD 1 billion mission’s samples have been reserved for future analysis. Scientists emphasize the need for further testing to deepen our understanding of the Bennu samples, alongside aspirations for more asteroid and comet sample returns. China is set to launch its own asteroid sample return mission this year.

Many scientists advocate for a mission to gather rocks and soil from the potentially water-rich dwarf planet Ceres in the main asteroid belt. Moons like Europa, orbiting Jupiter, and Enceladus, orbiting Saturn, are also viewed as intriguing watery worlds. Meanwhile, NASA is awaiting pickup of core samples from Mars, though their delivery process is on pause as the agency evaluates the quickest and most cost-effective means to bring them back.

"Are we alone?" McCoy pondered. "That’s one of the questions we are striving to answer." 

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Inputs from PTI