Asteroids may have brought water and organic matter to Earth

Asteroids that traveled from the fringes of the solar system more than 4.5 billion kilometers away may have brought water and organic matter to primordial Earth, a team of Japanese researchers said on Monday. The hypothesis, published in the scientific journal Nature Astronomy by the Japan Aerospace Exploration Agency and others, was drawn from an analysis of samples from the asteroid Ryugu collected by the space probe Hayabusa2. How the Earth, which was almost entirely made up of molten magma when it was first formed, ended up being covered in water remains a mystery. “In a broad sense, it is possible that small celestial bodies brought elements that led to water and life on Earth,” said Motoo Ito, senior researcher in geomaterials science at the Japan Science Agency. and marine and land-based technologies. In December 2020, a capsule that had been carried on a six-year mission by Hayabusa2 delivered to Earth more than 5.4 grams of surface material from the asteroid Ryugu, located more than 300 million km away. While the composition of Ryugu's particles closely matched that of Earth's water, there were nevertheless slight differences, leading the researchers to hypothesize that Earth could also obtain water from places other than Earth. asteroids. → Read also: Rainwater unfit for consumption everywhere on Earth An analysis of eight particles, totaling about 59 milligrams from the asteroid Ryugu, has made it possible to discover in almost all of them organic matter and water not in liquid form but in the form of a hydroxyl group consisting of an oxygen atom bonded to a hydrogen atom, with a composition similar to that of the water contained in cosmic dust and comets. Protected by a “cradle” of phyllosilicates, they are thought to have undergone harsh environmental changes after leaving the outer solar system, where water and organic matter are present. Organic zones composed of a material known as an aliphatic hydrocarbon have also been found in relatively coarse-grained phyllosilicates. The large surrounding grains, which are more resistant to heat, may have prevented water and organic matter from being weathered by the environment. Hayabusa2 left Earth in 2014 and reached its stationary position above Ryugu in June 2018 after traveling 3.2 billion km in an elliptical orbit around the Sun for more than three years. The probe touched down on the asteroid twice in the following year, collecting the first-ever subsurface samples from an asteroid. Researchers previously discovered that Ryugu, born from a parent body formed in the outer solar system, traveled to the inner solar system and that its particles contain amino acids – organic compounds said to be “source of life”. With MAP