When the solar system was first organizing itself, a disk of gas and dust took shape around the sun’s central mass. It eventually sorted itself into the system of planets we see today. But there are things we don’t know about how that happened. One observation that has been challenging to explain is the difference in composition we see between the outer and inner planets. Another is the “isotopic dichotomy” between the two major types of meteorites that hit Earth. Now ... Read even more
