A NASA spacecraft has returned asteroid samples that hold not only the pristine building blocks for life but also the salty remains of an ancient water world.

Samples of Bennu were brought back to Earth by NASA’s OSIRIS-REx spacecraft in 2023. Now, a pair of newly published papers reveal that the samples contain precursors to life that formed in a watery environment—a watery environment very similar to the one that prevailed on Earth before life emerged up to four billion years ago.

Scientists have detected organic compounds and minerals necessary for life in the samples collected by the OSIRIS-REx mission from a near-Earth asteroid named Bennu.