The findings provide the strongest evidence yet that asteroids may have planted the seeds of life on Earth. CAPE CANAVERAL, Fla. — Asteroid samples fetched by NASA hold not only the pristine building blocks for life but also the salty remains of an ancient water world, scientists reported Wednesday.

The asteroid Bennu contains a lot of organic molecules, including many essential building blocks of life, according to a study published in the journal Nature on Wednesday. It suggests that the chemistry that produced the asteroid may be occurring today on the ice moons of Jupiter and Saturn.

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