The team looked at two different isotopes of carbon in the chemicals, which included the nucleobases uracil and xanthine. The lighter version, carbon-12, is present on Earth in large amounts. Carbon-13 is more common in sweeping clouds of cold, interstellar gas. Large amounts of the stuff usually indicate the material did not form on
The ratio of carbon-13 to carbon-12 was unusually high in the two nucleobases, leading the team to conclude the materials likely formed in the meteorite itself rather than on Earth.
Click to expand...