MPIDS Colloquium: The "missing link" in planet formation
14:15 - 15:15
Prof. Jürgen Blum
Research Group Planet Formation, TU Braunschweig, Germany
Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
Prandtl Lecture Hall
The formation of planets is a multi-scale and multi-stage problem. It is known that planets form out of (sub-)micrometer-sized protoplanetary dust particles that condense in cooling protoplanetary disks. These dust particles then collide among each other, which initially leads to the formation of loose aggregates. However, laboratory experiments have shown that this growth stops when the ag-gregates have reached sizes of a few millimeters. Many theoretical concepts have been advocated to explain the further growth towards (multi-)kilometer objects. Bodies exceeding these sizes possess sufficiently strong gravitational attraction to accumulate mass in high-velocity mutual collisions. Owing to the great success of the Rosetta mission to comet 67P/Churyumov-Gerasimenko, we could show that comet 67P consists of mm-sized dust aggregates, which means that it could only be formed by a smooth gravitational collapse. Thus, we now have empirical evidence that the "missing link" in planet formation has been found.