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

Since the notion of the Anthropocene entered the discourse of environmental humanities, it has prompted multiple conceptual innovations. This paper focuses on one such case: the term planetary - and the adjacent genre of planetary thinking - theorized by a broad range of scholars. The original contribution of this paper lies in developing an astronomical concept of the planet, derived from the definition agreed by resolution 5A 2006 of International Astronomical Union, which defines planets based on their dynamical context. By means of philosophical interpretation of the definition's underlying assumptions, this paper articulates standalone philosophical implications of the astronomical concept: the contextualization of the planet in expanded ecology of the solar system, paired with the understanding of the planet as a structure of phase gradients and as a historical natural kind. Furthermore, I position the astronomical concept alongside theorizations of the planet by Latour, Stengers, Clark & Szerszynski as well as Chakrabarty, touching upon the Gaia hypothesis or the concept of geological history. Finally, I encourage deeper disciplinary interaction between astronomy and environmental humanities. The benefits of this interaction are highlighted in the concluding discussion concerning the multiplicity of planetary narratives and applications of the astronomical concept of the planet.