“The Habitability of Galaxies and the Spread of Life” with Raphaël Gobat (Catholic University of Valparaíso, Chile)

The idea of a plurality of worlds, in which the Universe is filled with a vast number of life-harboring planets similar to our own, has long fascinated philosophers and has become a durable part of popular culture. To this day no incontrovertibly habitable planet other than our own has been found, and this idea thus remains a bright hope. However, the rapid pace of exoplanet discoveries, and the large number of extrasolar planets now detected, have finally made possible statistical studies and the determination, albeit tentative, of true planetary distribution functions. Furthermore, our knowledge of the evolution of galaxies and the stars they contain is now mature enough that we can model their formation history from early times to the present day. By combining the two we can estimate the amount of potentially habitable planets in our galaxy and others. More speculative yet is the idea of “panspermia”, the exchange of life-seeding material between solar systems. However, while still entirely unproven, this concept can be explored on large scales through the application of habitability models to numerical simulations, yielding insights about the efficiency of possible seeding processes in different regions of the Milky Way.

Raphaël Gobat is a tenured assistant professor at the Catholic University of Valparaíso, in Chile. After graduating from the Ecole Polytechnique Fédérale de Lausanne (EPFL), he studied at the European Southern Observatory (ESO) and obtained is PhD from the Ludwig Maximilian University (LMU) in Munich, Germany. He then went on to work as a postdoctoral researcher at the Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), in France, and at the Korea Institute for Advanced Studies (KIAS) before moving to his current position in Valaparaíso. Raphaël Gobat is an astrophysicist specializing in very distant galaxies and galaxy clusters. Always fascinated by deep time, he maintains a strong interest in the history of life on Earth, which has led him to branch off into more astrobiological research subjects as well.

Webinar was recorded on April 7, 2022