Nothing in the universe is destroyed: all matter that exists, existed, or will exist comes from the debris of ancient stars from an early universe. A widely accepted hypothesis among astrobiologists is that the complex molecules that today structure life on Earth were formed in the universe as a result of chemical reactions produced by the death of stars. And these elements had to survive in the universe until they somehow reached Earth. Now, researchers from Tohoku University, Hokkaido University, JAMSTEC and NASA’s Goddard Space Flight Center have found evidence for ribose and other sugars essential for life in meteorites that fell to Earth . Which would show that these sugars, the basis for the chemistry of life, were formed in the early solar system, and reached Earth using these space rocks as a vehicle.
And how do we know that these sugars did not form on Earth and did not adhere to meteorites once they entered our planet? These sugars possessed different carbon isotope compositions, different from terrestrial biological sugars, indicating their extraterrestrial origin.
Specifically, the team analyzed three meteorites and found sugars in two of them.
According to lead author Yoshihiro Furukawa of Tohoku University: ” The analysis of sugars in meteorites is very difficult. In recent years, we have investigated the techniques of analysis of sugar in these samples and we have built our original method.”
What is the nature of these sugars?
It is about amino acids and nucleobases, compounds of vital importance for life.
It is not the first time that scientists have found sugars in meteorites, but the importance of this finding is that the sugars found are considered essential for life. Previous research, instead, revealed other sugar-related compounds (sugar acids and sugar alcohols) and the simpler sugar (dihydroxyacetone) that are instead considered essential for life.
A similar milestone occurred in 2018, when another scientific team found liquid water and complex elements, such as hydrocarbons and amino acids (the latter, the components of DNA), in meteorites that fell to Earth.
The formation of bio-essential sugars, including ribose, on the prebiotic Earth is considered possible . However, there is no geological evidence of its formation. Furthermore, it is not clear what sugar and how much was formed on the prebiotic (pre-life) Earth.
With current research showing the delivery of bio-essential sugars, it is plausible that extraterrestrial sugar contributed to the formation of primordial RNA on prebiotic Earth. Which means that it is quite possible that meteorites brought to Earth an indispensable factor in the origin of life.
Meteorites, carriers of the ingredients of life
The same type of hypothesis is established with water: many scientists believe that the first H2O molecules reached Earth as well, inside meteorites. Specifically, there is a hypothesis that establishes that, shortly after the formation of the planet, for 20 million years, the Earth was bombarded by millions of them, until it ended up forming the Earth’s oceans.
This means that each drop of water from the seas, or from your own body, could be billions of years old, and have traveled inside a meteorite for millions of kilometers to reach our planet.
Más información:
Extraterrestrial ribose and other sugars in primitive meteorites. Authors: Yoshihiro Furukawa, Yoshito Chikaraishi, Naohiko Ohkouchi, Nanako O. Ogawa, Daniel P. Glavin, Jason P. Dworkin, Chiaki Abe, and Tomoki Nakamura. Proceedings of the National Academy of Sciences, USA. DOI:10.1073/pnas.1907169116.
