Another Earth: An astronomical concept of the planet for the environmental humanities

Abstract

This paper contributes to the recently emerged genre of planetary thinking by diving into the astronomical concept of the planet – the conceptualization of the planet as a category of astronomical objects with distinct qualities and a degree of identity over time. This conceptualization is derived from a definition of planet as agreed by 5A 2006 resolution of International Astronomical Union, and it is discussed in terms of its two main philosophical implications: understanding of the planet as a gradient of phases of matter, and classification of the planet in philosophical terms as a historical natural kind. While doing so, the paper urges the readers to imagine: What if the foundations of planetary thinking did not lie in the Anthropocene debate, visual references on Earth photographs or metaphors borrowed from Earth System Science, but instead in the astronomical legacy of thinking about our planet as a member of a specific category of celestial bodies? To contrast the concept of a planet informed by its astronomical definition to current situation in environmental humanities, the paper further engages with contemporary planetary thinking, represented mainly by Nigel Clark and Bronislaw Szerszynski. The astronomical concept of the planet is put into critical conversation with their treatment, in order to underscore the need to read the planetary through the deep historicity implied by the astronomical concept. Finally, the paper wraps up with drafting the key stakes of planetary thinking based on the astronomical concept of the planet, hoping to motivate further investigations grounded in such approach.