The Hayabusa 2 spacecraft returned samples from Ryugu in 2020, and analysis of a small fraction of these samples has revealed essential components for life. Samples from the Ryugu asteroid contain uracil, one of the four building blocks of RNA, as well as niacin and other compounds important to living organisms. This supports the idea that the components of life were brought to Earth by space rocks.
Some of RNA's Building Blocks Came to Earth from Space
At the end of 2020, Japan's Hayabusa 2 probe brought 5,4 grams of asteroid dust from Ryugu, and multiple laboratories were able to take small samples of the material for analysis. At Hokkaido University in Japan, Yasuhiro Oba and his colleagues first soaked the samples in hot water for 20 hours, then in hydrochloric acid. They then looked for nucleobases in the resulting tea-like extracts. They followed a similar process to look for organic compounds.
Only 20 to 30 percent of the extracts were used for this study, and although the researchers started with samples weighing less than 20 milligrams, they were able to locate uracil and other chemical compounds. These substances have been discovered in extraterrestrial rocks before, but these discoveries were not made in pure samples from the Ryugu asteroid, but in meteorites that had previously been exposed to the elements on the Earth's surface.
In previous research, we were unable to completely dispel the idea that the nucleobases detected were contaminants from the terrestrial environment, Oba says. “This time, under careful contamination control, Ryugu samples have been freed from terrestrial contamination, which is strong evidence that uracil is actually present in extraterrestrial materials,” the researcher said.
The Ryugu asteroid sample that was transported to Earth has a strangely black hue.
If uracil is found, it means that other essential substances for life, which we cannot study due to the small size of the samples, may also be found in Ryugu. Fortunately, NASA's OSIRIS-REx probe carrying over 400 grams of asteroid dust is returning from another asteroid called Bennu and will land in September 2023.
According to Oba, we hope to find other compounds of interest there, as well as other nucleobases, as uracil will be found in much greater abundance in materials from Bennu.
Since asteroids like Ryugu and Bennu played an important role in the formation of planets in our solar system, it is almost certain that these materials were also present in early Earth. By analyzing the materials, we can determine what kind of prebiotic chemistry may have been present throughout our planet's early history. These components necessary for life may have been transported to Earth by similar asteroids.
Source: New Scientist
Günceleme: 22/03/2023 12:04