Colloquium: Comets as clues to the formation and evolution of planetesimals

The formation and evolution of planetesimals - the first massive bodies in the early Solar System - is a complex sequence of processes. I will review these processes and will draw conclusions about the properties of planetesimal-survivors into the contemporary Solar System. As an example, comets in general and comet 67P/Churyumov-Gerasimenko in
particular will be compared to the model results of a leftover planetesimal fragment. It turns out that comets can tell us a lot about the conditions in the young and evolving Solar System.