An ancient meteorite recorded its changing environment

An ancient meteorite recorded its changing environment. In the past decade or so, planetary scientists have significantly changed their view of the protoplanetary disk from which Earth condensed. Once described as having well-defined concentric zones, the disk is increasingly seen as a dynamic place whose materials could travel huge distances away from or toward the Sun. Now former University of California postdoc Justin Simon (currently a research scientist at NASA’s Johnson Space Center) and colleagues have used oxygen-isotope analysis to document what appears to be the wild ride of a meteorite fragment that formed early in the solar system’s history. The relative abundance of oxygen-16 and oxygen-17 indicates the radius at which the primitive material incorporated oxygen. That’s because solar radiation able to liberate ¹⁷O from carbon monoxide (C¹⁷O) is less attenuated as it travels through the disk than is the radiation that encounters the more prevalent...