For instance, scientists are aware that the objects in the solar system we see today, including Earth, formed around the sun from a disk of gas and dust. However, some of those objects, namely asteroids and comets, appear to consist of material that was not present in the disk — at least, the material shouldn't have been present in the locations those objects currently find themselves in. Instead, it'd make more sense for these items to have formed closer to the sun before being scattered farther afield. If Jupiter and the other giant planets migrated from where they formed, maybe asteroids and comets could've as well