Discovery of Liquid Water on Asteroid Ryugu

In a groundbreaking discovery, scientists have found that liquid water once flowed on the surface of the asteroid Ryugu, challenging previous notions about the early formation of the solar system. This discovery was made possible through the study of rock samples brought back by the Japanese spacecraft Hayabusa2 from the asteroid between 2018 and 2019.

Background on Asteroid Ryugu

Carbonaceous asteroids like Ryugu are considered fossil records of primordial materials formed 4.6 billion years ago. These asteroids are composed of ice and dust and contain untainted materials from the early solar system.

Before this research, scientists believed that water activity on asteroids was limited to a short period after the solar system’s formation. However, the new discovery suggests that liquid water existed on Ryugu’s surface long after the asteroid’s initial formation.

Details of the Scientific Study

The research team, led by Japanese scientist Tsuyoshi Iizuka, studied radioactive element isotopes in Ryugu’s rock samples. They used lutetium and hafnium isotopes as natural time markers to identify geological processes.

The team found that the samples contained higher amounts of hafnium isotopes compared to lutetium isotopes, indicating that fluids had leached lutetium from the rocks on the asteroid. This suggests that liquid water persisted longer than previously expected.

Significance of the Discovery in Understanding Earth’s Formation

This discovery could alter our understanding of planet formation, indicating that carbonaceous asteroids may have contained more water than previously thought. This implies that asteroids like Ryugu may have contributed significant amounts of water to the early Earth.

This finding could have a major impact on our understanding of the formation of Earth’s oceans and atmosphere in the planet’s early history.

Challenges and Techniques Used in the Research

The team faced significant challenges due to the small size of the samples, which were the size of a grain of rice. This required the development of new techniques for element separation and high-precision isotope analysis.

Iizuka stated, “We had to design new chemical methods to minimize element loss while isolating multiple elements from the same sample. Without this, we would not have been able to detect signs of late-stage water activity.”

Conclusion

This discovery represents a shift in how we understand the role of asteroids in delivering water to Earth and forming water systems. It suggests that Earth’s building blocks were wetter than previously believed, prompting a reevaluation of the initial conditions that helped make our planet habitable.