Before the discovery of the first extrasolar planet about 20 years ago it was thought that the global structure of the Solar System is not a coincidence, but rather a necessary consequence of the physics of the planetary formation process. Theoreticians therefore also predicted that planetary systems around other stars should be similar to our system at large. Observations have proven otherwise: with the counter of known extrasolar planets now at 3000, there is one word that describes them best: diversity – an astonishing diversity in terms of masses, orbits, temperatures, compositions, etc., showing that the theory of planet formation needed to be revised thoroughly. In this talk we will introduce the fundamental concepts of planet formation theory, discuss how extrasolar planets are the ideal laboratory to test theory against observations, and show how extrasolar planets continue to surprise to this day.

With Prof. Dr. Christoph Mordasini, University Bern