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

ABSTRACT

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.

KEYWORDS:

• Astronomy
• planets
• planetary thinking
• evolution
• geological history
• historical natural kinds
• cosmic ecology

Acknowledgment

This article has been written as the result of author’s guest research at Astronomy & Society Group, Leiden University. I would like to express my thanks to Pedro Russo, Frans Snik, Ignas Snellen and Yamila Miguel for their generosity in sharing their astronomical insights. Furthermore, I would like to thank Adam Frank, Brad Weslake, Michael Yuen, Valdis Silins and Carl C. Olsson for their valuable comments on early versions of the manuscript, and the four anonymous reviewers for suggestions that immensely strengthened the final version of this paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 In a different context, one could also refer to the wave of vitalist tendencies in new materialist philosophies (e.g. Bennett 2010).

2 Dwarf planets – such as Pluto – do not fulfil criterion (c), see Messeri (2010, 189).

3 Planetesimals are the initial aggregates of cosmic matter that coalesce in the proto-planetary disc around the young star. Hubble time is the time the universe needed to expand to its present state. This rather long timescale allows to account for different possible lifespans of host stars (Stern and Levinson 2002, 208).

4 This expanded understanding of ecology echoes remarks of some environmental humanities authors that have ventured into the realm of outer space studies, see Helmreich (2017, 304–305).

5 For detailed explanation of why intrinsic criteria are not sufficient, see Stern and Levinson (2002, 206). Additional arguments against treating planets as natural kinds have been formulated in Murzi (2007, 368–371).

6 For explanation of generative entrenchment, see Schank and Wimsatt (1986).

7 Analogously, we can think about stellar evolution as contingent historical process with limited set of recognizable and repeatable pathways. Hertzsprung–Russell diagram (H-R diagram) represents a plot of stars categorized according to their luminosity and colour spectrum, diagramming at the same time a virtual space of their possible evolutionary forms (Pierrehumbert 2011, 22–24). Applied to the case of planets, one can then speculate about H-R diagram of possible planetary states and their sequences.

8 Compare to Bawaka Country (2015).

9 This is well exemplified by Spivak (2012, 340–343), who treats the planet as an enigma of alterity, an ethical-political Other that confronts humans with imperatives and obligations. Her proposition works well in the context of the astronomical concept of the planet since it maintains the planet in the register of cosmic exteriority.

Additional information

Notes on contributors

Lukáš Likavčan

Lukáš Likavčan is a philosopher. His research focuses on philosophy of science & technology and environmental philosophy. He is Global Perspective on Society Postdoctoral Fellow at NYU Shanghai, and a guest researcher at Leiden Observatory. He is an author of Introduction to Comparative Planetology (2019).