Tiny bubbles might have helped to impose order on the rambunctious molecules that formed the precursors of life — a necessary step for life on Earth to evolve.

Billions of years ago, a haphazard soup of molecules was somehow organized sufficiently to form proteins, DNA and, ultimately, cells. Seeking to understand how, Dieter Braun at Ludwig–Maximilians University in Munich, Germany, and his colleagues examined whether biomolecules could become concentrated on the surface of a gas bubble. Such bubbles are common in porous rocks around hydrothermal vents — sea-floor structures that many scientists think were the cradle of life.

The researchers formed microscopic bubbles in a heated tank of water seeded with biomolecules such as RNA and DNA. Within 30 minutes, biomolecules had accumulated on the outer surfaces of the bubbles. The authors demonstrated that biomolecules can collect into cell-like capsules on the bubbles’ surfaces. The bubbles’ exteriors can also speed up chemical reactions that promote the replication of DNA and RNA.

The study offers a possible path by which early life overcame the forces of randomness in nature.