TOKYO -- A group of researchers from the University of Tokyo and elsewhere has found that a type of asteroid that contributed water to Earth's formation may have contained more than twice as much water than previously thought.
Samples from Hayabusa2 spacecraft offer new hints about Earth's formation

Japan's Hayabusa2 spacecraft brought samples from the asteroid Ryugu back to Earth. (JAXA)
TOKYO -- A group of researchers from the University of Tokyo and elsewhere has found that a type of asteroid that contributed water to Earth's formation may have contained more than twice as much water than previously thought.