that, because we humans have messed up Earth, it would be immoral to do the same to Mars. Adler Planetarium astronomer Grace Wolf-Chase admonishes us to clean up Earth’s mess before we mess up another planet. “Considering the possibility of extraterrestrial species motivates us to re-evaluate humanity’s history as stewards of Earth, and to examine critically human behaviors before migrating to other worlds” [2.93].
Would colonization be legal? The UN Outer Space Treaty, recall, holds that Mars, like other celestial locations, cannot be subject to national appropriation by claim of sovereignty, by means of use or occupation. Might the USA or China—whichever country lands first—simply stake a claim? “I don’t see how Mars could be anything but a land grab driven by homesteading rules,” pines Christopher Wanjek [2.91].
Among the many quandaries that the prospect of colonization raises is this: will earthlings living on Mars still be earthlings? Or, will evolution require such a level of adaptation that humans will become posthuman? Polish scientist Konrad Szocik along with his colleagues entertains this quandary and responds by recommending CRISPR gene editing to enhance adaptation. “It is worth keeping in mind that living in different—let’s call them unnatural places, which are not a part of the environment of evolutionary adaptedness—locations is not problematic per se, if humans are prepared in an appropriate way to live there” [2.82]. Astroethicists of responsibility must engage the question: Is it our moral right if not obligation to engineer the future of human evolution so that a successor species—a posthuman species—emerges?
Here is my tentative response: if a biosphere exists on Mars, then we should treat it as having intrinsic value. But if Mars is currently lifeless then, despite the interplanetary necessity for genetic engineering, we should take advantage of the opportunity to seed the Red Planet with life for the sake of its future. This becomes the moral warrant for both terraforming and colonization.
What about the mega vision of extending the habitat of Homo sapiens to outer space, turning earthlings into a transplanetary species? I applaud such a grand vision. I only add two grumbles, one scientific and the other theological. Scientifically, once Earth’s colonists have adapted to a significantly new off-Earth environment, their descendants may no longer be human. We will not be able to say confidently that a single transplanetary species has come into existence. Theologically, we ought not to expect a utopian life to commence on a new planet. We ought not to expect we will create El Dorado or a heaven in the heavens. Earth’s colonists to new worlds will bring with them a very ancient yet perduring pattern of living: sin.
2.3.10 How Do We Protect Earth from the Sky?
Even with colonists migrating from the third to the fourth planet, the vast majority of earthlings will remain living on Earth. Earth will continue to be our home for the foreseeable future. The ecological-ethical mandate is clear: if we Homo sapiens do not get our act together we’ll go extinct before Martian microbes will.
Earth is a dangerous place to live. The heavens threaten. The Sun occasionally launches solar flares, which fry electricity grids by generating intense currents in wires. More rare than solar flares but equally potent are blasts of radiation from a nearby γ-ray (gamma ray) burst. A short-hard γ-ray burst, caused by the violent merger of two black holes or two neutron stars or a combination, provides the most frightening scenario. If one such blast would be directed at Earth from within 200 parsecs away (less than 1% of the distance across the Milky Way), it would zap Earth with enough high-energy photons to wipe out 30% of the atmosphere’s protective ozone layer for nearly a decade.
There are more threats coming from Earth’s heavens. Comets and asteroids, when large in size, can explode on Earth’s surface with the impact of a nuclear bomb. It is widely believed among scientists that sixty-five million years ago an asteroid ten kilometers in diameter hit Earth and triggered the mass extinction of dinosaurs. Can we protect Earth from future asteroid catastrophes? The UN’s Science and Technical Subcommittee’s Near-Earth Object Working Group and its internal panel, Action Team 14, have been working on the details of an international approach since 2001.
The astroethical response to possible and probable futures is to prepare. These damage scenarios lead us to think ahead. We need to plan for our planet’s future, and we need to incorporate such possibilities into our planning. With regard to solar flares, fortunately, there are ways to mitigate the damage should it occur: engineers can protect the grid with fail-safes or by turning off the power in the face of an incoming blast. With regard to a comet or asteroid strike, we will be given advanced notice. A diversion strategy could be effective, perhaps by hitting the object while it is yet far away with a nuclear bomb. We have no way to prevent gamma ray bursts from striking our Earth, but we could provide protective shields in sanctuaries for life forms we wish to restart following the event. These matters belong to our quandary. Just how will we respond?
2.4 Levels of Intelligence in the Milky Way Metropolis
Is it likely that yet-to-become neighbors are already living in our Milky Way metropolis? Yes, indeed. “A conservative estimate,” speculates University of Arizona astrobiologist Chris Impey, “might be a billion habitable ‘spots’— terrestrial planets in conventionally defined habitable zones, plus moons of giant planet harboring liquid water—in the Milky Way alone. That number must be multiplied by 1011 for the number of ‘petri dishes’ in the observable cosmos” [2.34].
When we meet them, will they be like us? No, says philosopher of biology Michael Ruse. Something like us, perhaps; but not us. “It seems that natural selection can and does produce intelligent beings all the way up to humans. I confess that even if this can happen, I would think selection would more likely produce humanoids—beings like humans but not necessarily identical to us. There might be at least as many Wookies in the universe as there are humans” [2.75].
The first question the ratiocentric astrobiologist will ask about our extraterrestrial contacts will be this: Are they intelligent? If so, just how intelligent? We mean it when we employ a term such as ETI, extraterrestrial intelligence.
In anticipation of contact with alien intelligence in a form that reasonably resembles Homo sapiens on Earth, perhaps we should consider engagement with three possibilities: extraterrestrial biotic individuals who are inferior to us (intellectually less intelligent), our peers (equal in intelligence), and superior to us (more highly intelligent) [2.58]. Each of these three categories implies a different set of moral responsibilities [2.58].
Curiously, for decades prior to the advent of the field of astrobiology, astronomers and science fiction writers measured the variety of extraterrestrial beings according to scales of intelligence. The mere existence of astrocognitionists among astrobiologists demonstrates the preoccupation we have with intelligence. “The multidisciplinary field of astrocognition,” according to David Dunér, “could be generally defined as “the study of the origin, evolution and distribution of cognition in the Universe,” or simply “the study of the thinking Universe” [2.28]. Until recently, coffee conversation among astrobiologists distinguished between stupid microbial life, on the one hand, and intelligent or even super-intelligent aliens, on the other. Elsewhere I have argued that all life is intelligent, even microbial life; and what we are dealing with are relative levels of intelligence [2.61].7
Regardless of my position on continuity of intelligence, the astroethicist must speculate about possible and probable ETI scenarios. We may make new galactic friends with beings inferior to us in intelligence, equal to us in intelligence, and even superior to us in intelligence. Some might be hostile. Some might be friendly. Others might even be benevolent. Each possible extraterrestrial scenario would shape our terrestrial response and our responsibility. In what follows we will get specific about each scenario.
2.4.1 What is Our Responsibility Toward Intellectually
