Scientists have discovered uracil, a building block of life, on the asteroid Ryugu. According to Oba, an astrochemist at Hokkaido University in Sapporo, Japan, “The detection of uracil in the Ryugu sample is very important to clearly demonstrate that it is really present in extraterrestrial environments.” Uracil has been previously detected in samples from meteorites, including a rare class called CI-chondrites, which are abundant in organic compounds. However, those meteorites landed on Earth, leaving open the possibility they had been contaminated by humans or Earth’s atmosphere. The Ryugu samples were collected in space, making them the purest bits of the solar system scientists have studied to date (SN: 6/9/22). This means that the team could rule out the influence of terrestrial biology. Despite being given only about 10 milligrams of the Ryugu sample for analysis, Oba’s team was able to detect uracil and other nucleobases in meteorites previously (SN: 4/26/22).
