Samples extracted from a distant asteroid to Earth tested positive for RNA nucleobases, an essential component of life. Space rocks may have inundated Earth with the necessary elements for the chemical transition to the first biological metabolic processes to eventually occur.
The question of the origin of life is perhaps the foundation of all science, and although there are a number of theories that attempt to explain how biological evolutionary history reached such complexity, it is still largely unknown where the basic elements for life originated.
RNA Nucleobases Found in Asteroid
Until a few years ago, discussing the origin of life outside of Earth was a taboo attributed to pseudoscience, but as technology allows us to explore the exterior more, clues are slowly emerging that speak to us of elements that arrived on Earth from space. Carl Sagan himself used to say that we are made of star stuff, and now we not only know that the calcium in our bones comes from supernovas, but also that key elements of RNA came from space.
A team of Japanese researchers analyzed samples brought back by the Hayabusa2 spacecraft from Ryugu. Researchers from Hokkaido University in Japan say that the spacecraft collected two samples directly from the surface of the asteroid and delivered them to Earth in sealed capsules, so sample contamination is not a possibility, according to JAXA.
Astrochemists led by Yasuhiro Oba found surprising substances in the asteroid samples. According to the researchers, the dust brought back contains uracil, which is one of the four nitrogenous bases that make up RNA, as well as niacin, more commonly known as vitamin B3, which plays a fundamental role in metabolic processes.
“Scientists have previously found nucleobases and vitamins in certain carbon-rich meteorites, but there was always the question of contamination due to exposure to the Earth’s environment,” says astrochemist Yasuhiro Oba from Hokkaido University in Japan.
Uracil and Niacin Present in Space
To prevent the samples from being contaminated with elements present in the Earth’s atmosphere, Oba and his team used a new technique for the detection and identification of nucleobases on a small scale and in small quantities. Both samples obtained from different positions on the surface of Ryugu asteroid were submerged in water at high temperatures and then subjected to high-performance liquid chromatography along with high-resolution electrospray ionization mass spectrometry.
“We found uracil in the samples in small quantities, in the range of 6 to 32 parts per billion (ppb), while vitamin B3 was more abundant, in the range of 49 to 99 ppb,” says Oba. “Other biological molecules were also found in the sample, including a selection of amino acids, amines, and carboxylic acids, which are found in proteins and metabolism, respectively.”
For now, the discovery reinforces the theory that the essential components for life to arise on Earth could have come from distant asteroids. However, this is just the beginning of an astrobiological science based on the chemistry of the universe, as agencies such as NASA are looking to analyze more samples of asteroids brought back from space.
Story originally written in Spanish by Alejandra Martínez in Ecoosfera.