What planet are you on?
A planetary body that functions as a ‘whole’ is one that is capable of becoming something else — by Nigel Clark & Bronislaw Szerszynski
whole-Earth images encouraged us to view our home planet as a unity, set apart from its forbidding cosmic surroundings
What appears before us, for the first time, is a blue pearl-like sphere set against the inky blackness of space. Swathed in clouds, the planet stands out in sharp relief from the surrounding dark void. It appears radiant, life-like, bountiful. And if we could zoom out and see some more of that immensity of empty space, we might add, the planet seems fragile and precious.
But looks can be deceiving. This is not the Earth, but HD 189733b, discovered by astronomers on 6 October 2005 — a Jupiter-sized planet orbiting a sun some sixty-four light years away from our own solar system, that would appear blueish to the human eye (the image we see above is an artist’s impression).
And, rather than coming from the reflection of liquid oceans, astrophysicists suggest, this cobalt blue coloration is generated by atmospheric clouds dense with silicate particles. Winds, it is estimated, spiral around the planet at over five thousand miles an hour, driving silicate shards in a howling horizontal rain. This would make a typical moment on the surface of HD 189733b akin to being caught in the midst of an exploding plate-glass window. Scientists conclude that the planet has low prospects for hosting extra-terrestrial life.
Much has been said about photographs of our own planet taken during the Apollo missions. Emerging as an icon of ecological consciousness, whole-Earth images accentuated the contrast between a world imbued with life and the stark lifelessness of space. They encouraged us to view our home planet as a unity, a singular entity, a precious envelope of lively togetherness set apart from its forbidding cosmic surroundings.
how is it that a planet which looks so together from the outside has a tendency to self-differentiate?
Over subsequent decades, that vision has been filled out. We have learned a lot about how the living and non-living parts of our planet are bound together, how the components of the Earth system interact, how energy and matter cycle ceaselessly through planet-wide systems. But along the way, something else has come into relief: something important that a snapshot of our planet’s composed and alluring face could not tell us.
Geologist Jan Zalasiewicz, who is also chair of the Anthropocene Working Group, puts it like this: ‘The Earth seems to be less one planet, rather a number of different Earths that have succeeded each other in time, each with very different chemical, physical and biological states’
How is it that a planet which looks so together from the outside has a tendency to self-differentiate? Why does the Earth have this inclination — from time to time — to reorganize itself into something new, into a state and a set of behaviours that differ dramatically from that which came before?
the very interconnectivity that enables all the parts of our planet to operate as one can also take the Earth out of step with itself
Researchers studying how the Earth functions as a system have become increasingly aware that wholeness, integration and unity have another side. The same flows and cycles, the same dense network of connections that bind the outer Earth into a single system, can also be source of change. The very interconnectivity that enables all the parts of our planet to operate as one can also take the Earth out of step with itself.
In short, the sciences that have taken the planet-as-a-whole as their object of inquiry have grown ever more aware that out of unity comes difference, from wholeness comes a capacity to become otherwise, out of oneness comes multiplicity.
Clearly, this is an unfathomably complex process. To know exactly what was going on, any ‘observer’ would need to be as complicated, as dense with sensors and connections, as the field they are observing. But to put it simply, we can say that all complex systems have the ability to absorb pressures for change — to maintain their current shape — up to a point. Once that threshold is reached, the same pressures for change can become self-reinforcing, as they bounce and resound their way through the dense networks of interconnections that make up the system.
Western science is arriving rather late at an understanding of how to look after complex and changeable systems
Just as we know that flailing to keep a tipping canoe upright can eventually lead to a point of no return, so too is there a growing awareness that the Earth’s climate system can absorb inputs of greenhouse gases up to a certain limit — beyond which runaway change is likely to occur. And like many other complex systems, large and small, this is the way the Earth system operates — whether it is humans or any other part of the system which is generating the pressure for change.
There are, of course, many ways to understand such dynamics — which characterise most of the systems that we and other living things rely upon in our everyday existence as earthly beings. Western science, it can and should be argued, is arriving rather late at an understanding of how to look after complex and changeable systems that peoples all over the planet have been practicing for as long as they can remember — which can be very long indeed.
planets arrive at what they are today by passing through a series of world-altering transformations
One of the systems that is currently under pressure from human impacts is the great swirl of water and air currents that distributes heat from the Earth’s tropics to its cooler latitudes: the main driver of what we commonly call ‘weather’.
But we should keep in mind that a different but related system of flows and cycles, another formidably complex planetary system, is keeping those monstrous, shard-driving winds hurtling around HD 189733b.
For that other blue marble gleaming in the blackness of space is also an astronomical body imbued with unity and wholeness. And HD 189733b too is a planet whose oneness harbours multiplicity, whose own dense networks of interconnectivity instil a capacity to become other to itself. Whether or not life lurks somewhere beneath its seemingly inhospitable surface, the distant cobalt-hued sphere has also arrived at what it is today by passing through a series of world-altering transformations.
while we sympathize with the idea that in the context of our current global environment crisis ‘there is no Planet B’, there are good reasons to reflect on the expanding alphabet and grammar of celestial bodies
It is not coincidental that at much the same time that the multiplicity which inheres in the Earth system has be coming into relief, earth-based observers have been extending their gaze to take in a multitude of other astronomical bodies. New techniques for apprehending astronomical bodies have led to a rapidly growing register of planets. Since the early 1990s more than 4000 exoplanets — planets other than in our own solar system — have been ‘confirmed’, while thousands of others have been detected but await verification.
Perhaps more important than the sheer numbers is the diversity of these planets: the opening up of our earthbound sense of the different possible ways to ‘be’ a planet. So while we sympathize with the idea that in the context of our current global environment crisis ‘there is no Planet B’, there are good reasons to reflect on the expanding alphabet and grammar of celestial bodies.
Researchers are discovering astronomical bodies composed of all manner of different elements they are finding planets that orbit twin suns, recognising that many other planets drift free of any solar system at all, and learning more about the potential for planets or moons with subsurface oceans to host life.
this burgeoning vision of multi-planetarity can also help us to come to terms with the multiplicity that inheres in the planet we know best
Looking at the great multitude of forms, structures and behaviours that planets can adopt, argue astronomer Michael Summers and physicist James Trefil, helps prise our thinking away from various forms of terrestrial and stellar chauvinism: the parochial sense that Earth is the template for all life-supporting planets and that our own sun-planet arrangement is the model for all solar systems. But this burgeoning vision of multi-planetarity can also help us to come to terms with the multiplicity that inheres in the planet we know best.
A broader and more generous sense of planetary diversity serves to remind us there is no necessity to the current structural organization and operating state of the Earth. It shows us that the specific trajectory our home planet has followed, the series of transformations it has undergone over the last 4.5 billion years, are but a subset of the many pathways that Earth might have taken.
In this way, thinking planets in the multiple can encourage us to stretch our imaginations to take in possible futures for this planet that have yet to be tried. Or as we like to put it, comparative planetology helps open the way to speculative planetary thinking. And thinking speculatively about our planet, we would insist, is far too important to leave to any one discipline, any single knowledge formation, any one culture or civilization.
This post is adapted from material in Nigel Clark & Bronislaw Szerszynski (2020) Planetary Social Thought: The Anthropocene Challenge to the Social Sciences, Cambridge: Polity, Chapter 4.
