Scientists analysing material from the asteroid Bennu, returned to Earth by NASA's OSIRIS-REx mission, have discovered a rich array of complex chemicals essential for life. The findings, published in Nature, suggest that similar asteroids may have delivered the key ingredients for life on Earth billions of years ago.
Professor Sara Russell, cosmic mineralogist at the Natural History Museum in London and a lead author of the study, said the diversity of molecules and minerals in the samples was unlike any extraterrestrial material studied before. The samples contain phosphates, ammonia, over a dozen amino acids, and the five nucleobases that form RNA and DNA.
The Bennu material originated from a wet, salty world that shattered in a collision early in the solar system's history. Analysis indicates its parent body had underground brine lakes that left behind salts similar to those in dry lake beds on Earth. These conditions may have fostered the formation of organic compounds.
While life is not thought to have evolved on Bennu itself, the findings support the theory that asteroids delivered life's building blocks to Earth. Similar processes could have seeded other worlds, such as Mars or the icy moons of Jupiter and Saturn. The Natural History Museum's upcoming exhibition, 'Space: Could Life Exist Beyond Earth?', opening on 16 May, will showcase these results alongside other missions exploring these possibilities.
The UK-built Rosalind Franklin rover, set to land on Mars in 2029, will drill for signs of life. Meanwhile, the James Webb Space Telescope recently detected chemical signatures on the exoplanet K2-18b that, on Earth, are produced only by living organisms, though this is not yet proof of alien life.
