Astrobiology at ULiège
Does life exist elsewhere in the universe? This question has remained pure speculation for centuries, but it is now at the heart of a rapidly growing field of research: astrobiology. Multidisciplinary in nature, this field relies on the collaboration of biologists, chemists, biochemists, geologists, physicists, astrophysicists, historians of sciences, and philosophers. Its ambition is to study the origins, evolution, distribution and future of life in the Universe. The University of Liège now has a Research Unit dedicated to this fascinating field of research.
mong the many topics addressed by astrobiology, we find the formation of planetary systems; the origin of prebiotic organic compounds; the origin, evolution and limits of life on Earth; planetary habitability; the search for traces of life (biosignatures) in our solar system (e.g. on Mars) or beyond; and even the search for extraterrestrial civilizations (SETI).
The current growth of this field of research is explained by recent developments in several scientific disciplines. One of them is exoplanetology, the detection and study of planets orbiting stars other than the Sun. This discipline was born in 1995 with the first detection of a planet in orbit around another star similar to the Sun, a discovery that was awarded a Nobel Prize in 2019. Since then, more than four thousands of these exoplanets have been discovered at an ever-increasing rate, including several dozen considered "potentially habitable", i.e. rocky planets that could harbor conditions conducive to life on their surfaces. Thanks to this avalanche of detections, we now know that most stars host their own planetary systems, and that our galaxy alone contains several tens of billions of potentially habitable exoplanets.
Another field whose development has played a major role in the rise of astrobiology is the study of the limits of life, and more precisely the discovery of numerous organisms thriving in extreme physico-chemical conditions previously considered unsuitable for life (e.g. at very high temperatures or pressures, in very acidic environments, etc). By their adaptation to various conditions lethal to most organisms, these extremophiles have extended the range of terrestrial and extraterrestrial conditions potentially suitable for life. On the other hand, the study of the oldest traces of life on Earth has shown that life appeared and diversified on our planet much earlier than previously thought, making it more plausible that it appeared elsewhere in the Universe, where the conditions would be habitable.
The University of Liège is very active in different disciplines related to astrobiology, as illustrated this year by the Francqui Prize awarded to Michaël Gillon for his work in exoplanetology. In order to further optimize the development of astrobiology at the Liège and Belgian levels, notably through collaborations between experts from different disciplines and the FNRS Astrobiology contact group, Michaël Gillon, astrophysicist and FNRS Senior Research Associate, and his colleague Prof. Emmanuelle Javaux, paleobiologist and leading expert in the study of the first traces of life and its evolution, have recently created the Astrobiology Research Unit, entirely dedicated to this theme. This is a Belgian first that places the University of Liège at the forefront of the field at the national and also European level. Its first large-scale project, supported by BELSPO (Belgian Science Policy) is called "PORTAL " (Photosynthesis in rocky habitable exoplanets). It explores the possibility of photosynthesis on rocky habitable exoplanets in orbit around very cool low-mass stars, and is carried out in collaboration with many experts from ULiège and other Belgian and international institutions.
Members of the Astrobiology Research Unit are also active in several ESA and NASA space missions, including Exomars 2022, CHEOPS, and JWST, and other national and international projects dealing with the beginnings of life on Earth and possibly on Mars. Thanks to the unwavering support of the ULiège authorities, this new Research Unit aims to make a major scientific contribution to the study of life in the Universe.