A new study of asteroid Bennu’s rocks has revealed it formed at one of the most important addresses in the early solar system: the water-ice line, where temperatures were cold enough for water to freeze but the young Sun still kept rock hot.

Scientists at ETH Zurich studied 120 grams of material brought back by NASA’s OSIRIS-REx spacecraft in 2023. By measuring isotopes of iron, titanium and chromium — atomic fingerprints — they found Bennu mixes ingredients from both the inner and outer solar system, like a recipe combining two kitchens.

Why does this matter? Carbon-rich asteroids like Bennu are prime suspects for delivering water and the building blocks of life to the early Earth. Knowing exactly where they formed helps scientists map how those ingredients travelled across the young solar system.

Bennu’s makeup closely matches samples from Japan’s Ryugu asteroid and a rare meteorite family called CI chondrites, suggesting these bodies share a common birthplace near that ancient fire-and-ice boundary. The OSIRIS-REx capsule delivered its 120-gram sample to Earth in September 2023, and scientists say the pristine material will be studied for decades. Each new analysis peels back another layer of the 4.5-billion-year history written into Bennu’s rocks.