Seeking Aurora: on interstellar arks, deep space and desire

Perhaps it might be easier to seek to escape this world than to face its problems.

The hurricane raging through the Carribean, the flooding in Texas, India and Bangladesh, and mudslides and overflows in Seirra Leone and China are further manifestations of climate change’s aggravation of traditional weather patterns.

And the escalating, irresolvable standoff between a rogue North Korean state and an erratic US President has forced long dormant fears of nuclear conflict to the surface of our collective consciousness.

North Korea’s ramshackle nuclear capabilities remain unproven, but even a limited atomic exchange would have devastating consequences. The South Korean capital Seoul, a likely target in any conflict, has a population of some 10 million people. An explosion in such a densely populated area would not only kill hundreds of thousands of people in the vicinity of the strike and discharge radiation over much further distances. It would throw millions of tonnes of soot and debris into the upper atmosphere, blocking out the Sun’s light and causing surface temperatures and precipitation rates across much of the Earth to plummet, with catastrophic consequences for the production of food staples such as maize, rice and wheat. With the world’s total grain reserves capable of sustaining less than 100 days of global consumption, hundreds of millions across the globe would be at risk of famine.

Seeking God, seeking the stars

It seems that nuclear disarmament and climate change are intractable problems that are just too hard for us to solve. We have the technological and diplomatic machinery to do so, but the political challenges have so far proved insurmountable.

The problem, perhaps, is not just political – the sheer difficulty of summoning and organising a collective will to act – but philosophical, an unacknowledged, even subconscious, passivity: a secret thought that one day we will simply be able to leave this world, with all its complexity, behind, and start anew, elsewhere. It is impolitic to acknowledge it amidst so much exhortation to care for our planet, but human culture now, as always, is saturated with the desire for escape.

It’s a desire most apparent, perhaps, in religious faith. As Pope Francis’s influential 2014 encyclical on the environment and human ecology demonstrated, faith can be a powerful advocate for the wise stewardship of the Earth. But a dualistic perspective elevating spirit over matter continues to inform much religious sentiment. Conservative forms of all of the monotheistic faiths retain a millenarian strain, an expectation, often keenly anticipated, of a final conflagration in which the righteous will be saved.

It’s easy to mock the cruder forms of religious apocalypticism, but something like the same yearning for escape surfaces in some of today’s most avant-garde scientific thought.

2017 has not only been a year of floods, nuclear escalation and other sublunary trials, but of significant developments in the glamorous field of space exploration. The European and Chinese space agencies have moved plans forward for the development of a moon base. NASA hopes to put astronauts on Mars, or at least in the planet’s orbit, by the 2030s. SpaceX formulates ever more ambitious speculations for its reusable rocket-and-spaceship technology, including possibilities for using it to establish Martian colonies. Stephen Hawking has argued for the colonisation of the Solar System, and perhaps systems beyond, for the long-term sake of humanity. Warning of irreversible climate change, over-population and the dangers of asteroid collision Hawking suggested that ‘spreading out may be the only thing that saves us from ourselves. I am convinced that humans need to leave Earth.’ And this month’s edition of The Astrophysical Journal brings news of the confirmation of four Earth-like planets orbiting Tau Ceti, one of our closest neighbouring stars, two of which orbit within the ‘habitable zone’ where water and thus life is possible.

The relative closeness of the Tau Ceti system with its Sun-like star and planets has accorded it a special place in the science and literature of space travel. The star has featured in dozens of sci-fi novels, including major works by Robert Heinlein, Frank Herbert and Ursula Le Guin, and in classic film and TV such as Star Trek and Doctor Who. And Tau Ceti is the subject of one of the most powerful sci-fi tales of recent years, Kim Stanley Robinson’s 2015 Aurora, a visceral account of a 26th century expedition to colonise one of the system’s moons – ‘Aurora’ – identified as a possible Earth-analogue.

Starship travellers

Robinson’s story conveys the sheer grandeur and audacity of space exploration. The colonists travel on an interstellar ark, a vast starship designed to support some 2000 spacefarers and the myriad lifeforms and plants required to sustain them for a voyage spanning generations, and to provide the raw materials necessary for the terraforming of Aurora.

The ship is a convincing a picture of the technological sublime as anything in sci-fi. Managed by an artificial intelligence (AI) powered by quantum computing, the vessel is constructed around a spine several miles long connected by a set of ‘spokes’ to two orbiting rings, each with a dozen biomes, eco-systems sheltering environments corresponding to the Earth’s varied territories, including grassland, tundra, savannah, steppe and polar regions.

But the story, for all its wonders, is marked from its opening pages by a profound pessimism about the very possibility of travel beyond the Solar System. For Robinson, the stars are simply too far away. His ship moves at one-tenth the speed of light, the fastest velocity astrophysics can imagine propelling a vessel of sufficient size to house the cargo necessary to sustain a colonisation mission. Even travelling at such a speed the journey to Tau Ceti takes some 170 years. Robinson’s ship is powered by the most sophisticated nuclear fusion technologies that can be foreseen today. If we want to reduce the time it would take to reach the stars we would need to discover an alternative means of propulsion, one capable of overcoming the seemingly absolute constraint imposed by the speed of light.

It is possible to imagine what a solution might look like. One suggestion envisages a warp drive system that would create a ‘space-time bubble’ around a starship, allowing it to ride over the surface of space-time. Another suggests creating ‘traversable wormholes’ that poke tunnels through the fabric of the universe, hyperspace shortcuts enabling ships to jump from one region of the cosmos to another. But – as their originators acknowledge – these and other ingenious thought-experiments remain the stuff of abstract speculation, beyond any practical means of application we can conceive.

It seems to be a simple, infuriating, brute fact that a journey even to a neighbouring star would be an epic enterprise spanning generations, placing extraordinary demands on the resilience of the travellers and the technology available to them.

There would be profound political challenges. Any society organised to sustain a decades-long journey to the stars in a confined space that nobody can leave would have to be organised as some form of autocracy. Robinson describes, in increasingly harrowing detail, the political and social tensions that would accumulate. It’s true that his population is small enough to be able to make some decisions according through a form of direct democracy. The colonists assemble in plazas to debate and vote on critical issues, not unlike the citizens of ancient Athens.

But their freedoms are sharply constrained. Every political decision they take is subordinate to the imperative of supporting the ship’s mission. Work is allocated according to a command structure: many mundane jobs simply have to be done, and there are limited opportunities for self-determination. Strict controls are imposed upon birth rates to keep the population within manageable limits. The ship is effectively an authoritarian city-state, its order ultimately enforced by the ship’s computer, benign in everyday interactions, but capable of imposing its rule by force. It’s a system that was freely accepted by the colonists who volunteered to participate in the mission. But its bonds are felt keenly by the generations following them, destined from birth to live out their lives within the ship’s confines.

And for Robinson, the challenges of managing the physics of star travel and fractious human relations are eclipsed by a still profound problem: the impossibility of retaining a biological equilibrium within an enclosed ecosystem. The most sober lesson his novel seeks to impart is that the difficulties involved in sustaining a viable ecosystem capable of supporting a human colony within a closed space, for so many years, is too great.

It simply isn’t possible to regulate the intricate flows of energy and matter on which a biosphere depends within an atmosphere – vast at the spacecraft is – a trillion times smaller than the Earth. In a locked system toxins are not blown away across the skies, or washed away in oceans, as they are on Earth: they stick around, literally. Every element in the ship has be tracked, cleaned and recycled, endlessly. As one character puts it, trying to explain the complexities of starship management to a child:

’Oh, I’ve told you before. It’s always the same. Everything in here has to cycle in a balance. It’s like the teeter-totters at the playground … You don’t have to keep it perfectly level, but when one side hits the ground you have to have some legs to push it back up again. And there are so many teeter-totters, all going at different speeds up and down. So you can’t have any accidental moments when they all go down at once … And our ability to figure out how to do that depends on our models, and really, it’s too complex to model.’ This thought makes her grimace. ‘So we try to do everything by little bits and watch what happens. Because we don’t really understand.’

And the teeter-totters do go down, all the time. Diseases circulate. Elements get entangled with each other. Marginal imbalances accumulate. Robinson describes how a fractional disequilibrium between salts and phosphates that would go unnoticed on Earth builds up over the years, with deadly consequences. Bacteria breeds at faster rates than the ship’s citizens and livestock are able to absorb. Over time the effects of the ship’s island ecosystem become cruelly apparent. Animals get smaller. Toxins become more virulent. People get progressively less healthy and intelligent with each new generation as the gene pool diminishes.

In an article discussing the science that frames his story, Robinson argues that biology rather than physics presents the most fundamental impediment to the possibility of long-term space travel. The human body is more dependent on the Earth’s ecology than classic sci-fi has acknowledged:

Eighty percent of the DNA in our bodies is not human DNA, and this relatively new discovery is startling, because it forces us to realise that we are not discrete individuals, but biomes, like little forests or swamps. Most of the creatures inside us have to be functioning well for the system as a whole to be healthy.

Space exploration confronts a cruel paradox. Any spaceship small enough to travel at the necessary speed to travel to the stars won’t be big enough to harbour an ecosystem of sufficient size to support life. And it’s an issue that wouldn’t go away even if a mission succeeds in reaching its destination. The process of terraforming a dead planet with an ecosystem capable of supporting human habitation, or adapting the atmosphere of a living planet, would take centuries, perhaps thousands of years – we don’t really know. Through all that time the colonists would still have to live in artificial biomes, those of the orbiting ship and the domes within which they would live on the planet’s surface while overseeing the colonisation process. Aurora isn’t the only contemporary epic of inter-generational space travel to have been published in the full light of modern science. But it is the most pessimistic, siding with Arthur C Clarke’s observation that perhaps ‘the stars are not for Man’.

Thinking aloud

But it’s a pessimism that is unlikely to seep too far into the cultural and scientific industries that continue to circulate around the enthralling possibility of interstellar travel. Novelists and filmmakers continue to dream of travel to the stars. And research institutes continue to emerge dedicated to examining the possibility of space exploration. Indeed one of them, the 100 Year Starship programme, has the backing of NASA and the Defense Advanced Research Projects Agency (DARPA), the US military agency best known for laying the foundations for the internet and satellite-based navigation.

Novelists, filmmakers and physicists continue to generate ideas for finding a way round the fundamental issue: the unfathomable immensity of space. Much research focuses on the possibilities for long-term travel that might be opened by hibernation. If the body’s chemical processes can be slowed to glacial pace, and the sleepers safely revived after many decades, it would be possible to limit the need for inter-generational travel, with its human cost. It’s an idea Robinson explores himself in Aurora. But hibernating bodies are still bodies, not corpses: the sleepers would continue to age, albeit at a much slower rates, and any diseases they were harbouring when their big sleep began would continue to gestate and evolve. The body’s decay would be slowed, not frozen.

Another proposal suggests re-engineering humans to make them fitter for the demands of interstellar travel. New gene editing technologies indicate that it may be possible to create ‘genetically modified astronauts’, equipping them with a greater proportion of radiation-proof cells better able to withstand the exposure of deep space, and to re-engineer their genes to make them less dependent on the usual quotient of oxygen humans need to consume. It may even be possible to engineer kidney cells to synthesise the amino acids our bodies don’t usually make, and thus evolve a generation of humans able to produce more of their own nutrients.

Others have wondered about the possibilities of loading vessels with frozen embryos that could be birthed when the ship closes on its destination by ‘robot nannies’, which, with the assistance of films and libraries would socialise raise the infants till they were able to support themselves…

A still more fantastic suggestion has actually generated more interest than the others. As the science of AI has advanced it has become possible to speculate whether virtual minds might be able to travel to the stars as software embedded within a starship’s electronic circuitry. An intriguing article by Giulio Prisco for the Kurtzeil Network, a movement of transhumanists and other futurists dedicated to exploring Ray Kurtzeil’s concept of the ‘technological singularity’, argues for the possibility of creating ‘virtual e-crews’. The brain of each astronaut could be scanned and an intricate software model constructed, which could be uploaded to and run on appropriate hardware. Each crew member would exist as a carbon substrate within a neural network, an AI subsystem in a starship’s processing system. These bodiless intelligences would have no need for air, water, food, medical care or radiation shielding, could withstand extreme acceleration, and – crucially – fit within a relatively tiny craft, allowing the use of solar sails propelled by light energy, which in theory can reach velocities approaching the speed of light.

Prisco’s vision approaches the surreality of Charlie Stross’s mindbending 2005 novel Accelerando, which describes the voyage of a can-sized ship to the stars:

Here we are, sixty something human minds. We’ve been migrated – while still awake – right out of our own heads using an amazing combination of nanotechnology and electron spin resonance mapping, and we’re now running as software in an operating system designed to virtualise multiple physics models and provide a simulation of reality that doesn’t let us go mad from sensory deprivation! … And this whole package is about the size of a fingertip, crammed into a starship the size of your grandmother’s old Walkman, in orbit around a brown dwarf just over three light-years from home.

Interstellar gnostics

Here science becomes religion. The desire for space exploration has become so strong that it is pursued at any cost, a sentiment voiced by one of Robinson’s characters:

It’s an evolutionary urge, a biological imperative, something like reproduction itself. Possibly it may resemble something like a dandelion or a thistle releasing its seeds to the winds, so that most of the seeds will float away and die. But a certain percentage will take hold and grow.

Interviewed about his book, Robinson said:

I think there’s a certain craziness in it, or pointlessness – the point seems to be religious, and having to do with species immortality or something like that.

The willingness of many within the AI community to contemplate bodiless space exploration indicates an affinity with an ancient strand of religious thought, gnosticism, which yearns for the transcendence of the body to a realm of pure spirit. When pursued to its limits, it seems, the dream of space travel leads to regions of thought as strange as those of any metaphysical speculation. And yet it is a dream that may be worth holding on to not so much out of expectation that it will find a way of getting us into deep space as for the discoveries it might make that could help us maintain life here on Earth.

The tantalising prospect of space exploration has challenged generations of our most brilliant scientists to develop new technologies that have transformed life on this world. The intensive research that made the Apollo missions possible, for example, generated a series of innovations that provided the building blocks for the development of contemporary technologies such as the internet and the smartphone. As the 100 Year Starship mission statement puts it:

When we explore space, we garner the greatest benefits here at home. The challenge of traveling to another star system could generate transformative activities, knowledge, and technologies that would dramatically benefit every nation on Earth in the near term and years to come.

We may never be able to find technologies capable of taking us to the stars, but in the course of aspiring towards them we may discover everything we need to colonise our own Solar System. As Robinson himself argued in 2312, the book to which Aurora is a kind of sequel, colonisation of the system would be of value not only for its own sake but for supplementing our life on Earth. Other planets could be mined for materials no longer available here, it would be easier to gather intelligence about threats such as solar flares and asteroids, and regular contact with the atmospheres of worlds such as Venus and Jupiter would allow us greater insight into Earth’s ecosystems. Research into the possibilities of terraforming Mars has already yielded valuable insights into processes we can use to repair our own damaged ecosystems.

‘The Earth is the cradle of humanity, but one cannot live in a cradle forever,’ said Konstantin Tsiolkovsky, the great Soviet rocket scientist and mystic. But as we discover more about the problems of space travel we may need to appreciate that Earth is not just a starting point, but our home, for as long as our Sun continues to burn. Beyond that time, billions of years away, we can’t say.

Space is vaster and life is more intimately bound to this planet than Tsiolkovsky could have known. It seems unlikely that we will ever be able to give up the dream of finding new Earths. But seeking them, we may be better able to maintain this one.

The image above is a detail from the cover of Aurora by Kim Stanley Robinson, published by Orbit.