Nothing in the universe is destroyed: all matter that exists, existed or will exist comes from the debris of ancient stars in a primitive 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 from the death of stars. These elements had to survive in the universe until they somehow reached Earth. Now, researchers at Tohoku University, Hokkaido University, JAMSTEC, and NASA’s Goddard Space Flight Center have found evidence of ribose and other life-saving sugars in meteorites that fell to Earth. Which demonstrates that these sugars, the basis for the chemistry of life, formed in the solar system early on, and came to Earth using these space rocks as a vehicle.
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 had different compositions of carbon isotopes, therefore different from terrestrial biological sugars, indicating their extraterrestrial origin.
Specifically, the team analyzed three meteorites and found sugars in two of them.
According to the 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 sugar analysis in these samples and have constructed our original method".
What is the nature of these sugars?
These are amino acids and nucleobases, compounds that are of vital importance for life.
It is not the first time that scientists have found sugars in meteorites, but the importance of this finding lies in the fact that the sugars found are considered essential for life. Previous research, on the other hand, revealed other sugar-related compounds (sugar acids and sugar alcohols) and simpler sugar (dihydroxyacetone), which are not 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, in the prebiotic Earth is considered possible. However, there is no geological evidence of their formation. Moreover, 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 has contributed to the formation of primordial RNA on prebiotic Earth. Which means it’s very possible that meteorites brought the Earth an indispensable factor in the origin of life.
Meteorites, carriers of the ingredients of life
The same kind of hypothesis is established with water: many scientists believe that the first H2O molecules arrived on Earth also, inside meteorites. In particular, there is a hypothesis that, shortly after the formation of the planet, for 20 million years, the Earth was bombarded by millions of them, eventually forming the Earth’s oceans.
This means that every 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 miles to reach our planet.
For more information:
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.