In the research done in collaboration with NASA, samples of three different meteorites were analysed: Northwest Africa 801 (NWA 801), NWA 7020 and Murchison. They all belong to a group of carbonaceous chondrites, typically rich in organic molecules, in which amino acids and sugars were previously found. The largest amount of sugars were found in the Murchison sample due to using a different extraction method than in the previous studies, with a sugar ribose detected.
So what is so special about ribose? It is one of the most crucial molecules in living organisms, heavily involved in metabolism and makes up RNA – a highly functional biopolymer in cells, participating in protein synthesis, gene expression and many more. Modified ribose is a building block of DNA, the importance of which is incontestable.
The abundance of ribose in living organisms could potentially contaminate the meteorite sample and prove the study unreliable. There is, however, a way to distinguish between molecules of space and Earth origin.
Carbon, the element on which the known life is based, is usually found in its most stable form, consisting of six electrons, protons and neutrons. Approximately 1.1% of carbon atoms on Earth contain not six but seven neutrons in their core. The isotopes can be easily detected and quantified with the available analytical methods.
The ribose molecules found in the Murchison sample were significantly enriched with the carbon isotope, exceeding beyond possible biological values. This finding strongly suggests the space origin, rather than Earth contamination with the sugar.
Many questions regarding origins of life and extra-terrestrial life seem to be nurturing humanity for centuries. The new study doesn’t provide an answer but might be a clue and inspiration for more extensive research. Was the life brought to Earth from outside? Are we not alone in the Universe?
There is still a lot to find out.
