This "Skeptic's Collection" column is dedicated to the life, work, and memory of Prof. Stephen Hawking, Lucasian Professor of theoretical physics and cosmology, Cambridge University, United Kingdom. "To strive, to seek, to find, and not to yield." -- Alfred, Lord Tennyson, "Ulysses”
If you have not seen the movie Interstellar, with Matthew McConaughey, Anne Hathaway, Mackenzie Foy, and John Lithgow, you should run – not walk – to the nearest theater or streaming service and watch it. Interstellar is a not just a science-fiction (SF) movie, it is a science-fiction movie, i.e., it does not cut any corners in terms of depicting the actual consequences of near-light travel, e.g., time dilation, black-hole physics, etc. (In that respect, Interstellar is a cinematic fraternal twin to Dan Simmons's excellent science-fiction novels Hyperion and The Fall of Hyperion.) Many of our most admired science fiction sagas – Star Trek, Farscape, Babylon 5, Star Wars, etc. – skate over the sociological and psychological consequences of near-light travel by the simple expedient of ignoring relavitity, leaving entire universes of potential reflection and exploration unattended. We concentrate on the science and forget the people. Prof. Kip Thorne, a Cal Tech Nobel Prize winner, has recently written a virtuoso book, The Science of “Interstellar,” that tackles explaining the science of the movie to an educated lay audience. But, presumptuous as it sounds, I want to supplement Prof. Thorne’s book by similarly tackling what I call “The Sociology of ‘Interstellar’”. To that end, I propose a radical thesis: the most formidable problems standing in the way of interstellar exploration will eventually prove to be, not technological, but sociological. The most formidable obstacles lie not in the stars or in our machines, but in ourselves.
In the world of Interstellar, the resources of near-future Earth are on the brink of exhaustion because of humans’ irresponsible and short-sighted exploitation of their home planet. Water is scarce. Crops fail. (The only way humans can eke out a bare subsistence from our ravaged world is by developing increasingly hardy varieties of genetically engineered corn.) There is a planet-wide Dust Bowl. The New York Yankees are reduced to playing sand-lot, pick-up games of baseball with local teams for food and lodging. McConaughey’s character, Cooper, a farmer, is a member of the penultimate generation for whom the planet will be marginally habitable. The next generation, that of his daughter, Murphy (“Murph” ... Mackenzie Foy as Murph at age 10, Ellen Burstyn as grown-up), is the generation that, in order for humanity to survive, must leave our exhausted earth and colonize other worlds.
At this point of crisis, a wormhole is discovered in orbit around Saturn. Because wormholes are inherently unstable, persisting only perhaps a fraction of a second, the permanence of the wormhole decisively indicates that it is an artifact of high intelligence. (Disclosing the builders of the wormhole would spoil the movie.) A project is undertaken by the sparse remnants of NASA to launch a spacecraft, the Endurance, to fly to Saturn, enter the wormhole, presumably emerge in some distant part of our, or another, galaxy, and begin prospecting for habitable worlds. There is real reason to hope: automated probes, sent through the wormhole in advance of human explorers, transmit back information about four potential candidate worlds, all orbiting a supermassive black hole the human astronauts, who will follow them in the Endurance, appropriately christen “Gargantua”.
To travel to the vicinity of the wormhole, the four-person Endurance crew – plus what I think is the coolest humanly intelligent robot ever to appear in an SF movie – undertake a 3-year journey to Saturn. No surprises here. They are traveling fast but far less than the speed of light over great but far less than cosmologically significant distances. It is when they traverse the wormhole and begin to orbit the worlds around the black hole Gargantua that relationships, as well as spacetime itself, begin to warp. It is then that questions arise about the limits and capabilities of human individuals and human societies.
The first such question, in fact, one of the milder questions -- by now actually rather cliche among the scientifically literate -- is the way the intense gravitational fields encountered near Gargantua, combined with the immense distances traversed by communication signals to Earth, result in the rapid aging, relative to the Endurance, of the loved ones Cooper, et al., left behind vs. the essentially non-aging, relative to Earth, of people on board the Endurance, who are subject to the time dilation resulting from Gargantua's immense gravitational potential. Video-conferencing with Murph and her brother Tom (Timothee Chalamet) reveals that, during the astronauts' brief time of the Endurance reference frame, decades have passed on Earth: Tom now has grey hair, has gotten married, and is a father; Cooper's father has passed; Murph, now a young woman, has matured into a scientific prodigy; etc., etc. This begs questions of tectonic significance: when traveling near the speed of light and experiencing radically different times in different relativistic reference frames, how are humans to maintain vital relationships ... and even can those relationships, so constitutive of the human condition, be maintained at all? And what, anyway, does "maintain" even mean in such a context? Relativistically significant gravitational potentials will tear matter apart. Will the associated time dilation, relative to remote observers, do as much damage to human relationships, and therefore to the human spirit?
But the consequences of actually landing on the surface of one of the four candidate worlds orbiting Gargantua are, if anything, even more wrenching. The more intense a gravitational potential, the slower time passes as observed from a reference frame arbitrarily remote from that potential. In the case of that one candidate world, the difference is significant. (The dialogue among the Endurance astronauts at this point, if transcribed and read with care, would constitute the framework for an excellent first course in general relativity.) In the specific case of this one candidate world, the strength of Gargantua's gravitational field at that point -- dictated by the mass of Gargantua and the distance of the candidate world from Gargantua's event horizon -- means that, for each hour the astronauts spend on the candidate world's surface, seven years pass on Earth. Go to bed and get a good eight hours of sleep on the candidate world, and when you wake up, it will be 7 years / hour x 8 hours = 56 years later on Earth than when you went to bed.
Given that the entirety of planet Earth is living on borrowed time, the counsel of Dr. Brand (Anne Hathaway), an Endurance astronaut and the daughter of Cooper's professor and mentor on Earth (Michael Caine), is especially urgent: time must be considered a scarce resource. Every hour spent on the planet's surface is seven years subtracted, not only from the physical life of our planet, but from the viability of its socio-political structures and the very psychology of its inhabitants. As the environment breaks down, so do the bonds holding together societies, political systems, and human relationships.
(In fact, the equations describing time near a black hole indicate that, as one approaches the event horizon, time passes more and more slowly [at least for a non-rotating black hole ... an important qualification ... but let's not get lost in the weeds], and in fact, precisely at the event horizon, time simply stops. An observer outside the event horizon would therefore see an in-falling object "get stuck" on the event horizon, like a fly on flypaper. What happens with respect to time inside the event horizon? No one knows. Attempting to calculate that means attempting to calculate the square root of a negative number [i.e., rs > r in the above linked article]: general relativity breaks down.)
There are multitudes of other aspects of the sociology of Interstellar we could explore. One of the more enticing, in fact, is the potential relationship between humanly intelligent robots, like the robot on the Endurance, who is de facto the fifth member of the Endurance crew, and human beings. Could such robots serve as, essentially, human surrogates as the possibility of human-to-human relationships undergoes gradual attrition because of relativistic time dilation? Such robots could be programmed to provide emotional comfort to humans without, for all that, being subject to feelings of bereavement through humans' absence. "Comfort robots" could support without needing to be supported by their human companions. (This is, of course, just a form of the classic "Turing problem": if the responses of a robot are indistinguishable from those of a human being, then is there really a difference at all? Are phenotypic differences really all that decisive? This would probably be an even sharper question during a future age when technology enabled light-speed travel. Robots would incorporate cybernetic human parts -- basically, benevolent cyborgs as in the later Terminator movies -- and vice versa.) They might serve the same purpose as "comfort animals" for emotionally fragile humans. I find that possibility at once horrifying and intriguing. But I think a more compelling issue is what Interstellar implicitly says about the implications of human mortality for the exploration of "cosmological" space.
The human species evolved in an environment that neither rewarded nor encouraged long-term thinking. We needed fire to cook our food, warm our caves, and keep predators away tonight and maybe tomorrow night. Large-scale use of wood certainly would lead to gradual deforestation, along with the associated ecological and social dislocations. But the key word is "gradually". Only with millennia of time did it become obvious that humans needed to develop long-term planning to deal with the consequences of advancing technology and its impact on the environment. Quite candidly, we are still not very good at this. We still habitually choose fossil fuels for the next five years over renewable, non-polluting alternatives for the next five hundred, with the result that, sometime during the next century, e.g., San Diego itself will become Sea World. And the root of that problem, in turn, is dual.
First of all, humans are a very short-lived species. Consequently, we find long-term planning difficult because our very lives are not long-term. A 7-year delay occasioned by an hour on the candidate planet's surface is roughly 10 percent of a typical human lifetime in the First World of the 21st century. Perhaps somewhere in the Universe there are intelligent species with typical lifetimes measured in say 10,000-year increments and perhaps billion-year histories as civilizations (as distinct from homo sapiens sapiens, which has been around about 150,000 years). Think of the ent-trees in Tolkien's Lord of the Rings or the Vorlon of Babylon 5. Either that, or there are species that, though as short-lived as humans, have developed socio-political structures and practices, unimaginably more advanced and enlightened than their human counterparts, that permit planning cycles measured in multiple millennia, short individual lives notwithstanding ... whichever.
The second reason humans are not good at long-term planning is because we are, perhaps all species at some point are, incorrigibly tribal. We care more about "people like us over here" than about "people like them over there". I have written about human tribalism within the comparatively parochial context of interplanetary exploration. I strongly suspect that there is a causal relationship between limited lifetimes and limited spheres of care for others, though I will not speculate on which way the cause-effect arrow points. Regardless of which is cause and which is effect, however, it should be clear that serious exploration over cosmologically significant distances, as in Interstellar, will require planning and coordination over scales we can scarcely imagine now, especially if the exploration is to be accomplished by beings within very limited life-spans. I hardly need say that such planning and cooperation will require correspondingly profound social and political -- even religious ... perhaps especially religious -- changes. We will have to learn to think of ourselves as human beings first and as Americans, Russians, gay, straight, Caucasian, black, etc., second, just as American colonists in the early Republic had to learn to think of themselves as Americans first and Virginians, Georgians, Pennsylvanians, etc.,, second -- except on a stupendously larger scale. We have to learn to think cosmologically -- politically and socially, not just astronomically.
I hope I am wrong, but I am not optimistic. (But then, as a "para-professional skeptic," I am never optimistic about much of anything!) Observing the current xenophobia and the lengths to which nations and their people are willing to go, and the distortions to their political values and systems they are willing to tolerate, to preserve their latent "Other-phobia" virginally intact, together with the self-inflicted myopia of the "There is no Planet B" (of course there isn't if we refuse to even look for it ... duh!) ideology, at the very least, we are not likely to apply for membership in any United Federation of Planets anytime soon. The Caretakers in Carl Sagan's Contact would laugh us out of the Galaxy! But then, I have to remember ... the Caretakers of Contact did not laugh us out of the Galaxy, and on the contrary treated the human species with meticulous respect. Furthermore, after the impact of the Chixulub meteor 65 million years ago, and after the great end-Permian extinction 180 million years before that, the prospects for life-as-such, life-per-se, life-tout-court on Earth would hardly have been a draw on the smart money. Even if nothing else, we are an adaptable species, socio-politically as well as evolutionarily. So when I reflect too long on human folly and its potentially fatal consequences, I like to recur to William Faulkner's great Nobel Prize acceptance speech:
I believe that man will not merely endure: he will prevail. He is immortal, not because he alone among creatures has an inexhaustible voice, but because he has a soul, a spirit capable of compassion and sacrifice and endurance. The poet's, the writer's, duty is to write about these things. It is his privilege to help man endure by lifting his heart, by reminding him of the courage and honor and hope and pride and compassion and pity and sacrifice which have been the glory of his past. The poet's voice need not merely be the record of man, it can be one of the props, the pillars to help him endure and prevail.
So, though it may be in spite of ourselves, there is reason to be optimistic that the starship Endurance may well carry a more prophetic name than we perhaps dare believe.
James R. Cowles