Rock and dust samples retrieved by NASA from the asteroid Bennu exhibit some of the chemical building blocks of life, according to research that provides some of the best evidence to date that such space rocks may have seeded early Earth with the raw ingredients that fostered the emergence of living organisms.

Molecules friendly to life have been found in samples of the asteroid Bennu, which NASA collected with a robotic probe five years ago.

Rock and dust samples from the Bennu asteroid contain molecules that are the "key to life" on Earth, NASA officials announced on Wednesday.