Asteroid Ryugu may hold clues to origins of life, solar system

The nearly-kilometer-long 162173 Ryugu asteroid had a sample brought back by JAXA's Hayabusa2 mission, and the findings can reveal new insights on the birth of the solar system.

Asteroid illustrative (photo credit: Wikimedia Commons)
Asteroid illustrative
(photo credit: Wikimedia Commons)

 A nearly-kilometer-long asteroid may contain minerals that shed light on the birth of the solar system and the origin of life on Earth, according to new studies.

The asteroid in question is 162173 Ryugu, which sits between Mars and Earth. Ryugu is a C-type asteroid, the most common kind in the solar system, the meteors from which almost rarely ever survive a trip through the atmosphere.

This is why the Hayabusa2 mission from the Japan Aerospace Exploration Agency (JAXA) to retrieve a sample from this asteroid was so important. It had launched in 2014, arrived at 2018 and returned in December 2020 for careful analysis by scientists, the findings of which were published in two articles in the peer-reviewed academic journal Nature Astronomy.

C-type asteroids, also known as carbonaceous, are thought to contain primordial materials from the nebula that essentially gave birth to the solar system as we know it. 

But according to the analysis of the sample brought back, Ryugu is no ordinary C-type asteroid. Rather, it seems to be the parent body of CI chondrite meteorites, an especially rare kind that has almost never survived a trip through Earth's atmosphere. 

 This is a colored view of the C-type asteroid 162173 Ryugu, seen by the ONC-T camera on board of Hayabusa2. (credit: Wikimedia Commons) This is a colored view of the C-type asteroid 162173 Ryugu, seen by the ONC-T camera on board of Hayabusa2. (credit: Wikimedia Commons)

This was determined by measuring the bulk density of the sample, itself made of incredibly dark fragments that reflect around just 2% of the light hitting them and are rich in water and organic matter, which was lower than known carbonaceous meteorites.

This means that the asteroid itself likely consists of many porous rocks, allowing empty pockets to exist between grains that could have allowed gas or liquids through - something that preliminary Hayabusa2 data had hinted at, according to Space.com.

And CI chondrite meteorites have another important quality: their chemical composition is similar to the Sun's photosphere.

"Imagine if you could take all of the gas away from the Sun and were just left with a vestige of other elements… you're left with a CI chondrite," explained Curtin University planetary scientist Phil Bland, who was not involved with the studies, according to ABC.

This is especially important because it is essentially an early image of the solar system's earliest moments. And because the Ryugu sample was studied so carefully, without exposing the sample to the Earth's atmosphere and instead studying it in a sealed environment filled with purified nitrogen or in a vacuum chamber, there is, therefore, no other sample like it, making it an invaluable source of information.

Understanding the formation of the solar system can give us a better understanding of the mechanisms of space and how the solar system evolved - including on the origins of life itself.

This is because C-type asteroids are thought to have water. In fact, it is this type of asteroids that many experts believe were what brought water and organic material to Earth in the first place, essentially planting the seeds for the development of life.

Research on the Ryugu sample will continue, but there is possibly more data to be gained from studying other C-type asteroid samples - and one such sample is currently on its way. The 500-meter wide 101955 Bennu is another C-type asteroid between Earth and Mars, and was the target of NASA's Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission. The spacecraft has gathered a sample and is slated for arrival on Earth in late-2023.

But time, and research, will tell what further clues will be found on the origins of life, the solar system and the other mysteries of the cosmos.