How did the Earth, believed to have been covered in bubbling oceans of magma billions of years ago, transform into the ‘blue planet’ and become covered in water?



  • In an article published in the journal Nature Astronomy, scientists from Japan suggest that water and organic materials might have been brought to our planet from the outer edges of the solar system.
  • The scientists made the hypothesis after analysing samples from the asteroid Ryugu, collected by the Japan Aerospace Exploration Agency’s (JAXA) Hayabusa-2 probe, which had brought 5.4 grams of rocks and dust from the asteroid to Earth in December 2020.
  • The Hayabusa-2 mission was launched in December 2014 when the spacecraft was sent on a six-year voyage to study the asteroid Ryugu.


What is the Hayabusa-2 mission?

  • The Hayabasu-2 mission was launched in December 2014 when the spacecraft was sent on a six-year-long voyage to study the asteroid Ryugu and collect samples that it is now bringing back to the Earth.
  • The spacecraft arrived at the asteroid in mid-2018 after which it deployed two rovers and a small lander onto the surface. In 2019, the spacecraft fired an impactor into the asteroid’s surface to create an artificial crater with a diameter of a little more than 10 metres, which allowed it to collect the samples.
  • As per NASA, the asteroid is thought to be made up mostly of nickel and iron. Asteroids like Ryugu are interesting for several reasons, perhaps foremost because they are near the Earth and might, one day in the far future, pose an impact threat.
  • Hayabasu-2’s predecessor, the Hayabusa mission brought back samples from the asteroid Itokawa in 2010.
  • After dropping off the capsule on the Earth (in December 2020) containing the sample, the spacecraft continued to move further to another asteroid called 1998 KY26 where it will reach by July 2031.