Earth’s water came from asteroids, claim Japanese astronomers

Japan’s Hayabusa2 space probe claims asteroids are the first source of water and organic matter on Earth.

  • Japanese astronomers find asteroids to be the first ever source of water and organic matter on Earth.
  • This analysis came from the samples collected by Japan’s Hayabusa2 from the Ryugu asteroid.
  • Japan’s Hayabusa2 was launched in 2014, reached above Ryugu in 2018 and returned back safely to Earth in 2020.

Japanese astronomers have claimed asteroids to be the first ever source of water and organic matter on Earth. The discovery comes after tests were run on the Ryugu asteroid’s samples which were delivered back to Earth by Japan’s Hayabusa2 spacecraft.

Japan’s Hayabusa2 was launched in 2014 and travelled around 3.2 billion km in an orbit around the Sun for three years to reach its position above Ryugu in June 2018. It collected the samples in early 2019 and landed safely back on Earth in Australia in 2020.


How did the astronomers reach this finding?

Kyodo News recently reported the findings revealed in a report by Nature Astronomy, a scientific journal. It elaborated on how the Earth which was molten magma once in all its content, now has 71 percent of its surface covered in ocean water.

The samples of Ryugu, which is about 300 million km away, contained surface dust and material which the spacecraft picked from below the surface. The report stated that the particles from Ryugu exhibited almost a similar compositional match to that of the water on the Earth. There were certain minor differences that eventually led the researchers to suspect that the Earth may have other sources of water than just the asteroids.

An analysis of the Ryugu asteroid’s eight particles that are present in most of its organic matter and water, which is found not in liquid but in the form of a hydroxyl group (a group composed of one oxygen atom bonded to one hydrogen atom), has the similar composition to that of the water found in comets and cosmic dust. Researchers also found that the particles from Ryugu contain amino acids which are organic compounds, also known as the “source of life on Earth.”

Hayabusa2’s predecessor mission, the first Hayabusa mission, delivered back samples from the Itokawa asteroid in 2010. The analysis of such particles from asteroids helps in getting an insight into various factors including the creation, evolution, and the potential future of the solar system.