Amino acids, the building blocks necessary for life, were previously found in samples of 4.6-billion-year-old rocks from an asteroid called Bennu, delivered to Earth in 2023 by NASA’s OSIRIS-REx mission. How those amino acids—the molecules that create proteins and peptides in DNA—formed in space was a mystery, but new research led by Penn State scientists shows they could have originated in an icy-cold, radioactive environment at the dawn of Earth’s solar system.

According to the researchers, who published new findings in the Proceedings of the National Academy of Sciences, some amino acids in the asteroid Bennu samples likely formed in a different way than was previously thought, in the harsh conditions of the early solar system.