Ancient Asteroid Sample Contains Crucial Clues About Solar System

Ancient asteroid samples contain crucial clues about the solar system, a new study has revealed.

The study, published in Nature Astronomy, presents findings from Japanese Hayabusa2, a mission conducted in 2019 by Japanese state space agency JAXA to retrieve samples from the asteroid Ryugu. The spacecraft returned to Earth in 2020 after extracting 5 grams of particles from the asteroid.

Scientists keep a close eye on Ryugu, which is about half a mile wide, because it is a potential danger to Earth.

A team of researchers from the Japan Agency for Marine-Earth Science and Technology found that the particles from the asteroid are like no other. According to the study, the particles are "pristine" and offer never before seen clues about the solar system.

An illustration showing an asteroid and Earth. A new study analyzes pristine particles taken from the asteroid Ryugu by a Japanese spacecraft. dottedhippo/Getty

"Ryugu particles are the most uncontaminated and unfractionated extraterrestrial materials studied so far, and provide the best available match to the bulk Solar System composition," the study said.

These uncontaminated particles can provide information about how life began on Earth.

Some experts believe that asteroids are the source of the Earth's water. Many studies suggest that asteroids rained down on the Earth as they moved further from the sun and developed hydrated minerals.

This means Ryugu's particles can provide insights into how the Earth became habitable.

"Volatile and organic-rich C-type asteroids may have been one of the main sources of Earth's water," the study said. "Our best insight into their chemistry is currently provided by carbonaceous chondritic meteorites, but the meteorite record is biased: only the strongest types survive atmospheric entry and are then modified by interaction with the terrestrial environment."

Another discovery from the particles was particularly "puzzling," the study said.

Information within the particles suggests that Ryugu is from a hydrated class of rock called CI-chondrite, as they are full of water. Yet previous observations of the asteroid's orbit suggested it was made from CY chondrites, a class of dehydrated rock.

"The fact that the Ryugu particles are not related to the CY chondrites, which show clear mineralogical evidence for dehydration, is puzzling," the study said.

According to the study, CI chondrites "are widely used as a proxy for the bulk Solar System composition." This means scientists may be able to use the particles to learn more about the beginnings of the solar system.

Before the asteroid sample missions, the only particles available for scientists to study were pieces of rock that had fallen to Earth by a coincidence. Their particles are not nearly as pristine as those collected on Hayabusa2. Such rocks on earth are usually contaminated from passing through the Earth's atmosphere.

Ryugu's particles, however, are in the same condition they were in when the solar system began, according to a Vice story.