Researchers find building blocks for earthly life on asteroid Ryugu

Did life come from outer space after all? Scientists have been advocating this theory for a long time. An analysis of the rock samples from the asteroid Ryugu supports it.

A team led by Toshiki Koga from the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) in Yokosuka examined the samples that the Hayabusa2 probe brought to Earth from the asteroid Ryugu in 2020. They found all five nucleobases, the building blocks for the genetic material of earthly life, they write in the journal Nature Astronomy.

The genetic information is stored in deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). DNA consists of the nucleobases adenine (A), cytosine (C), guanine (G), and thymine (T). RNA contains uracil (U) instead of thymine. The Japanese researchers were able to detect all five in the asteroid rock. They therefore originate from the early days of the solar system.

Bennu also contains the five nucleobases

Last year, researchers in the USA made a comparable discovery: In the samples that the Osiris-Rex mission brought to Earth from the asteroid Bennu in 2023, they also found the five nucleobases as well as a large proportion of the amino acids found in earthly life. This supports the theory that the building blocks for life could have come to Earth from the outside.

While nucleobases have been detected in meteorites that have fallen to Earth before, such as in the Murchison meteorite that hit Earth in Australia in 1969, there was a risk with these finds that they were introduced after impact on Earth. This is not the case with the samples from Ryugu and Bennu, which makes these two findings significant.

Hayabusa2 launched in 2014 to the asteroid Ryugu, where it arrived in 2018. The spacecraft completed an extensive research program there. This included deploying several landers on the celestial body. One of them, Mascot, was developed by the German Aerospace Center (DLR) and its French counterpart Centre National d’Études Spatiales (CNES).

The highlight of the mission was Hayabusa2 landing on Ryugu in 2019. It took samples there and then brought them to Earth. At the end of 2020, the container with the samples reached Earth. They have been analyzed in detail ever since.

(wpl)