An international team has suggested asteroids striking Earth may have sparked the growth of life after the so-called “essential building blocks of life” were found inside space rocks.
Scientists have confirmed that sugars, which are key biological compounds for supporting life, have been discovered inside asteroids.
These include ribose and other bio-essential sugars such as arabinose and xylose – all of which are essential for the proteins to be built that carry out life processes.
According to the findings published in the Proceedings of the National Academy of Sciences journal today (November 18), it means it is an asteroid bombardment may have begun life as we know it on Earth.
Lead study author Yoshihiro Furukawa, of Tohoku University, Japan, said: “Other important building blocks of life have been found in meteorites previously, including amino acids (components of proteins) and nucleobases (components of DNA and RNA), but sugars have been a missing piece among the major building blocks of life.
“The research provides the first direct evidence of ribose in space and the delivery of the sugar to Earth.
“The extraterrestrial sugar might have contributed to the formation of RNA on the prebiotic Earth which possibly led to the origin of life.”
Co-author Jason Dworkin, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, US, added: “It is remarkable that a molecule as fragile as ribose could be detected in such ancient material.
“These results will help guide our analyses of pristine samples from primitive asteroids Ryugu and Bennu, to be returned by the Japan Aerospace Exploration Agency’s Hayabusa2 and NASA’s OSIRIS-REx spacecraft.”
While DNA is the very basis of life, it is now believed RNA, which also has the ability to carry instructions on how to create and operate a living organism, may have predated DNA.
DNA then eventually came to replace RNA as the base structure for the formation of life.
“The sugar in DNA (2-deoxyribose) was not detected in any of the meteorites analyzed in this study,” explained Danny Glavin, another co-author at NASA Goddard.
“This is important since there could have been a delivery bias of extraterrestrial ribose to the early Earth which is consistent with the hypothesis that RNA evolved first.”