NASA brought back samples from asteroid Bennu. They revealed clues about the possible origins of life.

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 findings provide the strongest evidence yet that asteroids may have planted the seeds of life on Earth and that these ingredients were mingling with water almost right from the start.

"That's the kind of environment that could have been essential to the steps that lead from elements to life," said the Smithsonian Institution's Tim McCoy, one of the lead study authors.