Scientists find evidence of flowing water on Ryugu’s ancient parent asteroid. 'It was a genuine surprise!'

Liquid water flowed across the surface of the asteroid that birthed the near-Earth object (NEO) Ryugu much later than scientists had thought possible, a new study finds.

The discovery that water existed in liquid form a billion years after the parent body of Ryugu formed came from the study of rock samples collected from the NEO by Japan's Hayabusa2 probe between 2018 and 2019, and returned to Earth on Dec. 5, 2020.

Carbonaceous asteroids like the spinning-top-shaped Ryugu have long been known to form from ice and dust in the outer solar system as the planets were forming around the infant sun around 4.6 billion years ago. Thus, objects like Ryugu are thought to contain a "fossil record" of unspoiled material from the dawn of our planetary system. However, before this research, scientist