The pre-requisites and ingredients for life seem to be abundantly available in the universe. However, we have yet to find any evidence for extraterrestrial life. Our search for life beyond the solar system is steadfastly focused on searching for habitable planets. But what do we mean by ‘habitable’? Habitable for whom, and for how long? It is not clear that the conditions for the emergence of life (the Abiogenesis Habitable Zone) are the same as the conditions for sustaining life on a planet. Conventional models of habitability that consider mostly the physics and chemistry of habitability may not be sufficient to truly appreciate the ‘evolution of habitability’.
As a planet evolves, it may lose the potential for life to emerge but may still support a biosphere. Indeed, it may lose habitability altogether, as has been speculated has happened with Venus and Mars. In this talk, Adi will argue that biospheres could play a crucial role in maintaining habitable conditions on their host planets by interacting with the planetary environment.
If it is the case that only inhabited planets are habitable, then we have so far ignored what may be the dominant parameter controlling the habitability of a planet: the life on it.
Aditya Chopra is a visiting fellow at the Research School of Astronomy and Astrophysics at the Australian National University. Aditya is using our current knowledge about the origin and evolution of life on Earth over the last ~4 billion years to better understand the potential for, and the nature of, life elsewhere in the universe. One of his research themes is the investigation of the role that life plays in keeping its planet habitable, and to identify processes which might have been co-opted by life to regulate Earth’s habitability at different epochs. Such biotic processes might also offer detectable biosignatures of alien life beyond Earth! Aditya has spent time as a Marie Skłodowska-Curie Postdoctoral Fellow at the University of Groningen in the oLife Fellowship Programme. He has degrees in Chemistry and Astronomy and completed his PhD at the Research School of Earth Sciences and Mt Stromlo Observatory at The Australian National University.
Webinar was recorded on March 17, 2022