The planetary turn has become remarkably widespread across the sciences and humanities. Runkel documents its proliferation in fields as varied as urban studies, where scholars speak of planetary urbanization; geopolitics, with calls for planetary geopolitics; political economy, in analyses of the planetary mine and the planet factory; feminism, with appeals for planetary feminism; and health research, where the concept of planetary health responds to the framework of planetary boundaries. Behind this vocabulary lie two distinct currents. The first is an earth-system-scientific perspective that views the planet macroscopically as a totality. The second is a posthumanist, social-scientific perspective that sees the planet as a world of radical alterity in which the specifically human is woven into more-than-human collectives.

The first current has an identifiable origin. In 1999, climate researcher Hans Joachim Schellnhuber proposed in Nature that earth system analysis had initiated a second Copernican revolution, one that would reverse the first by enabling humanity to look back on its planet and perceive a single, complex, dynamic entity far from thermodynamic equilibrium, the Earth system. Schellnhuber envisioned the technological means for this holistic perception: satellite-based bird’s-eye observation, digital twins of the planet built through modeling and virtual simulation, and experimental miniaturizations of Earth dynamics such as the Biosphere II experiments. He formalized the planetary machinery in the formula E=(N,H), where the Earth system comprises the ecosphere and the human factor, the latter splitting into an anthroposphere and an emergent global subject. In a modernist gesture, he cast Gaia as the Earth system, Shiva as its destructive opposition, and Prometheus as the human factor, insisting that the second Copernican revolution would be completed only if humanity took responsibility for planetary management.

Runkel shows that this promethean vision carries a striking irony. Blumenberg had once asserted that the starry sky was the one thing that could not be a product of human skill or an object of human intervention. The proliferation of earth-observation satellites, and especially the mega-constellations whose numbers could rise to as many as 100,000 in the coming years, is literally contradicting that claim. The visible night sky is becoming a second nature, an orbital interior of capital that Runkel, adapting David Harvey’s concept of the spatio-temporal fix, calls an orbital fix. The very satellites that promise a triumphant, macroscopic view of the planet are simultaneously obstructing humanity’s view of the stars, reshaping the cosmological backdrop of the Anthropocene.

The second current of planetary thinking emerged from literary theory and postcolonial critique. In a 1997 lecture, Gayatri C. Spivak proposed overwriting the globe with the planet in an age of galloping globalization, arguing that the planet exists in the sign of alterity and belongs to a different system. Wai Chee Dimock similarly described literature as a durable artificial form of life whose proper analytical unit is the entire planet. Dipesh Chakrabarty later sharpened the distinction between the globe and the planet, observing that the word globe is not the same word as in global warming, and that the histories of humanity and nature have definitively collapsed into one another. He argued that the planet places us in the same position as every other creature, a non-anthropocentric perspective that has energized debates on more-than-human geographies.

Yet this posthumanist current also invokes the Copernican metaphor. The editors of a recent German-language volume on more-than-human geographies declare that the field is in the process of radically transforming how science is thought, a turning point so fundamental that they call it a second Copernican turn in science. Contributor Heike Egner goes further, arguing that the Anthropocene hypothesis catapults humanity to the threshold of an epistemic leap comparable to the original Copernican turn: then we lost the Earth as the center of the world, now we lose ourselves. Runkel notes that this rhetoric reproduces, almost point for point, the Freudian drama of cosmic humiliation and compensatory triumph that Blumenberg traced through the post-Copernican tradition.

That tradition is the analytical heart of the paper. Runkel recounts how Copernicus himself was less revolutionary than posterity suggests, seeking mainly to simplify the calculation of planetary motions by making the Earth mobile. The real upheaval came later, through Kepler’s refinements, Tycho Brahe’s data, and Galileo’s telescope, which elevated the Earth to the rank of a star. Blumenberg’s decisive insight was that the Copernican reform became history not as a theoretical event but as a metaphor: the reconstruction of the cosmic edifice became the sign of a new self-location of humanity, or the loss of any locatable place at all. The geocentric position, Runkel emphasizes following Blumenberg, only acquired theological dogma status after it was metaphorized; before Copernicus, Earth’s central position carried no metaphysical weight for salvation.

The metaphor then split into two enduring readings. One camp, exemplified by Goethe, celebrated the new freedoms of thought and the triumph of human reason, which Copernicus had made independent of all cosmic orientation. The other, exemplified by Nietzsche, lamented the self-diminishment of man, who since Copernicus seems to roll ever faster from the center toward the void. Freud canonized this tension as the first of three great humiliations, followed by Darwin’s biological and psychoanalysis’s psychological blows. Kant, famously, had already claimed a second Copernican turn for philosophy, proposing that objects conform to our cognition rather than the reverse, a move Blumenberg read as an act of self-preservation against the supposed consequences of the first turn. Husserl later sought compensation in the Earth as the primordial ark, the unshakeable ground of all experience against the infinite Copernican horizons of mathematical physics.

Read through this genealogy, the two contemporary planetary camps reveal themselves as the latest variation of the same vertical tension. The earth-systematic, promethean planetarism performs a symbolic new geocentrism, a triumphal total perspective delivered by satellites and digital twins, even as those technologies build a real planetarium that screens off the stars. The posthumanist, Gaian planetarism enacts a renewed trauma of de-anthropocentrization, dissolving the autonomous knowing subject into planetary relationality, yet it remains dependent on human scales of earthly groundedness and anthropomorphic analogy. Runkel suggests it is less a new Copernican turn than a productive working-through of Kant’s act of self-preservation, a post- rather than anti-Kantian project, occasionally shading into a transhumanist longing for the more-than-terrestrial.

Blumenberg’s anthropological punchline, Runkel argues, is that this ambivalence itself generates what he called Selbstbehauptung, self-assertion: the strategic compensation of existential insecurity through the technical appropriation of the world. In the planetary age, that self-assertion is increasingly more-than-terrestrial. The earth system sciences are epistemologically and technologically bound to spaceflight, from the iconic Earthrise and Blue Marble photographs to today’s satellite constellations. Posthumanist thinkers call for an astrobiological description of ourselves and express a desire for planetary evolution. Yet the space age itself delivered a sobering lesson: the Earth appeared as a cosmic exception, and even the discovery of exoplanets and water on Mars has merely shifted the boundary of possible encounters with alien life beyond practical reach. With crewed spaceflight unlikely to be economically or ethically sensible in the near future, the interpretation of spectral lines hinting at exoplanetary biosignatures will matter not astronautically but astronoetically, as Blumenberg termed the thinking about whether and why to travel at all.

The paper closes with a skeptical verdict on the euphoric welcome of planetary thinking in geography. The calls for a new Copernican turn, Runkel contends, are evidence of the unbroken discursive power of the metaphor, which conceals continuity behind the appearance of rupture and functions as a micromyth legitimating new epistemic claims. The hope that planetary thinking might found an entirely new cosmology overcoming the post-Copernican ambivalence of triumph and trauma is, he suggests, a pious wish. Perhaps, though, that is the real insight: the return to Copernicus points not to a new symbolic order but to the impossibility of founding one. Blumenberg’s own conclusion applies equally to both planetary camps: only as an experience of turning back is it accepted that there are no alternatives to the Earth for humanity, just as there are no alternatives of reason to the human.

Subject of Research: A metaphorological critique of the second Copernican turn metaphor in contemporary planetary thinking and geography

Article Title: Mehr-als-irdische Geographien und die zweite Kopernikanische Wende des planetarischen Denkens. Eine metaphorologische Kritik

Article References: Runkel, S. (2026). Mehr-als-irdische Geographien und die zweite Kopernikanische Wende des planetarischen Denkens. Eine metaphorologische Kritik. Geographica Helvetica, 81(3), 517-533. https://doi.org/10.5194/gh-81-517-2026

Image Credits: AI Generated

DOI: 10.5194/gh-81-517-2026

Keywords: planetary thinking, Copernican turn, Hans Blumenberg, metaphorology, Anthropocene, earth system science, posthumanism, geography, more-than-human, satellites, Spivak, Chakrabarty