Asteroids, small airless bodies within the inner solar system, are theorized to have contributed water and chemical building blocks of life to Earth billions of years ago. Although meteorites on Earth come from asteroids,

Japanese scientists detected all five nucleobases — building blocks of DNA and RNA — in samples returned from asteroid Bennu by NASA’s OSIRIS-REx mission. NASA’s OSIRIS-REx mission brought back 121.6 grams of asteroid Bennu,