Sugars, Gum, Stardust Found in NASA's Asteroid Bennu Samples

Summary

The asteroid Bennu continues to provide new clues to scientists’ biggest questions about the formation of the early solar system and the origins of life. As part of the ongoing study of pristine samples delivered to Earth by NASA’s OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer) spacecraft, three new papers published Tuesday by the journals Nature Geosciences and Nature Astronomy present remarkable discoveries: sugars essential for biology, a gum-like substance not seen before in astromaterials, and an unexpectedly high abundance of dust produced by supernova explosions. Sugars essential to life Scientists led by Yoshihiro Furukawa of Tohoku University in Japan found sugars essential for biology on Earth in the Bennu samples, detailing their findings in the journal Nature Geoscience. The five-carbon sugar ribose and, for the first time in an extraterrestrial sample, six-carbon glucose were found. Although these sugars are not evidence of life, their detection, along with previous detections of amino acids, nucleobases, and carboxylic acids in Bennu samples, show building blocks of biological molecules were widespread throughout the solar system. For life on Earth, the sugars deoxyribose and ribose are key building blocks of DNA and RNA, respectively. DNA is the primary carrier of genetic information in cells. RNA performs numerous functions, and life as we know it could not exist without it. Ribose in RNA is used in the molecule’s sugar-phosphate “backbone” that connects a string of information-carrying nucleobases. VIDEO “All five nucleobases used to construct both DNA and RNA, along with phosphates, have already been found in the Bennu samples brought to Earth by OSIRIS-REx,” said Furukawa. “The new discovery of ribose means that all of the components to form the molecule RNA are present in Bennu.” The discovery of ribose in asteroid samples is not a complete surprise. Ribose has previously been found in two m...