by Marc Kaufman
That view was reprised, of all places, on The Colbert Report, the fake cable TV news show that often gets views through the back door that would never make it through the front. Following reports about the Vatican astrobiology conference in 2009, host Stephen Colbert invited one of the Vatican astronomers from Arizona, Brother Guy Consolmagno, onto the show. Brother Guy, as he wanted to be called, was trained as a physicist at MIT before becoming a priest and later earned a doctorate in planetary science from Arizona State University, so he’s an astronomy professional as well as a devout Catholic. But he had the same welcoming embrace ready for any “extraterrestrial brothers.” After all, he told Colbert, the Church has highlighted extraterrestrials for centuries in the form of angels. “The whole mythology of angels in the Christian and Jewish tradition shows that the Church, the people who wrote the Bible, were not afraid of other intelligent creatures who are also worshipping God.”
Colbert wasn’t buying it. “Why would the Catholic church do this?” he asked in both the mock and serious incredulity of a playacting but serious Catholic. “Doesn’t this upset our place at the center of God’s creation?” Consolmagno responded that God wanted us to learn about the universe as a way of knowing His work. Unimpressed, Colbert replied, “If we accept there is alien life on other planets, doesn’t that totally blow Jesus out of the water? He came down and became man, not creature.” Then came the clincher. Could Jesus, or Jesus-like saviors, be walking among and saving intelligent creatures on other faraway planets, too? Answered Consolmagno: “I’m not there, but it could be.”
This extraterrestrial debate actually goes back in recorded fashion to the fourth-century B.C. Greeks. Epicurus, the philosopher of pleasure and pain, argued what became known as the “plurality of worlds” position, that life did exist on other celestial bodies. Aristotle, however, held a strong one-world view that did not allow for life beyond Earth and, adopted by Christianity, dominated the Western world well into the Renaissance. Books by Steven Dick, a retired historian at NASA, and Notre Dame University professor Michael Crowe detail the impressive constancy and heat of the debate over the centuries, as well as the elaborate deductions of men including Descartes, Immanuel Kant, and Benjamin Franklin as they tried to reach and defend positions with essentially no scientific data. Much of the debate involved whether or not the Christian worldview allowed for the possibility of a “plurality of worlds.”
One of the most strident voices was that of founding father Thomas Paine, who, in The Age of Reason, wrote that a belief in Christianity and in what was then considered the enlightened acceptance of a plurality of worlds “cannot be held together in the same mind; and he who thinks that he believes in both has thought but little of either.” In mid-nineteenth-century England, the man considered the greatest intellect of the time—geologist and moral philosopher William Whewell, master of Trinity College, Cambridge University—wrote first anonymously and then publicly that those who argued many planets were inhabited were wrong on the science, and also that central aspects of Christianity and the possible presence of extraterrestrial life were incompatible.
Whewell’s defense of the Christian narrative against the “plurality of worlds” caused an intellectual firestorm that inspired some fifty articles and twenty books within several years. The biggest point of contention was not that belief in Christianity was undermining the evidence of science, as might be argued today. Rather, the plurality-of-worlds position, which was then taught in many schools, was believed by most men and women of science to be entirely consistent with the existence of an omnipresent God. What made Whewell’s scientific and intellectual critics irate was that he was implying they had not thought through the implications of their convictions about the plurality of worlds and were therefore compromised Christians.
The implications of astrobiology hardly end with religion. A 2009 workshop on the possible societal challenges raised by astrobiology introduced a variety of others, many of them quite practical. In fact, that was the point of the two-day, NASA-sponsored meeting: to bring other disciplines into the discussion about how to respond to possible breakthroughs in extraterrestrial science. Those invited included forty-two professionals ranging from scientists to priests, from anthropologists and philosophers to ethicists. It was hardly a fringy group; many more men wore blue blazers than ponytails.
At the opening, SETI pioneer Frank Drake acknowledged that the task of the workshop, even the convening of the group, was on the far periphery of both science and astrobiology. Long an optimist about finding extraterrestrial life, however, Drake saw change coming. “When the time of a detection comes, this group will be among the most central in the world in dealing with the consequences, good and bad, of what just happened.”
Margaret Race, the workshop organizer and a SETI Institute biologist, likened the astrobiological moment to the genetics and biotechnology revolutions of the 1990s, when scientists began to regularly move genes around and a layer of ethicists came in to set limits and create guidelines. “Scientists and engineers have been making the decisions about how to conduct missions and investigate space since the start of the space age,” she told the group. “We now need others.”
The meeting divided into groups based on areas of expertise, and over the two and a half days the list of issues to confront grew quite long. Some involved more familiar topics such as how to define life, how to look for life, and how to integrate potential extraterrestrial life into established religious and social views. But other, seldom broached questions came up that put astrobiology into a different light. For instance, heated discussions broke out about the moral responsibilities of humans to life found on other planets. And if a responsibility did exist, was it absolute, or did it slide up and down a scale with the simplicity or complexity of the life? Taking it a step further, some wondered whether extraterrestrial life could be patented and owned by future explorers. The workshop also heard discussion about terra-forming, the process of modifying a planet (usually Mars) enough to create an atmosphere and then a biosphere that could support humans. Once the stuff of science fiction, it’s now the subject of serious scientific and ethical discussion.
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The modern religious, ethical, even philosophical debate about the current and future findings of modern astrobiology is in its infancy. But the purely secular debate about extraterrestrial life—the one that considers whether the discovery is possible at all—is fast losing ground to the march of science. The three primary viewpoints in that debate still have their advocates but here’s why, at the finish of my own extended encounters with astrobiology, I have come to believe the science only points to one conclusion.
OPTION 1. We are alone in the universe and Earth is the only planet, moon, asteroid, comet, or undiscovered other body anywhere with life.
From the perspective of science and logic, this position is essentially a nonstarter. We can search for life beyond Earth for centuries and not find it, but that doesn’t mean it isn’t there. It just means we didn’t find it. As philosopher and astrobiology thinker Carol Cleland put it, this is not a case where the absence of evidence is evidence of absence. From a logical perspective, she said, sometimes an absence of evidence can and does mean something doesn’t exist. If you go to Africa on the hunch that the brontosaurus still roams the land and you don’t find any, then the absence of evidence is compelling. But that isn’t the case with our efforts so far to find life of any sort beyond Earth. Astrobiology is a huge and dynamic endeavor and it has, in its modern incarnation, only just begun. Especially given the vastness of the canvas and the discoveries of the past decade, I don’t see how anyone can reasonably come to the conclusion or make the claim that Earth and only Earth has life.
OPTION 2. Only Earth has complex life.
Sure, microbes might exist in nooks and crannies, deep underground or in liquid or icy water, but too many things have to go right for a life-form to evolve beyond a basically single-cell state. This is the argument
of the influential book Rare Earth, by paleontologist Peter Ward and astronomer Donald Brownlee. While microbial life is probably widespread across the cosmos, they write, it takes enormous good fortune for life to evolve into more complex forms because of the innumerable ways that extinction—to the point of planetary sterilization—can be inflicted. Even the Earth has had many close calls that could have snuffed out all life; the fact that evolution continued, they argue, is something of an improbable fluke. The argument has its followers, but I find the conclusion unconvincing.
First, having “life” come together from nonlife is generally viewed as the hard part, the step that scientists don’t understand and can’t replicate. Even when future headlines read that “life” has been created in a lab, the claim will be a substantial exaggeration for years to come since the “life” created will be made from molecules and compounds manufactured by humans. What synthetic biologists are doing is remarkable, but nobody is close to understanding how life can be formed from nonliving parts that haven’t been previously engineered or changed by scientists. That’s why the cartoon resonates of a professor at the blackboard diagramming the origin of life in exquisite but incomplete detail. The blackboard equations and processes lead to life only because toward the end of the intricate formula, a balloon appears that matter-of-factly declares, “Miracle Happens.” I’m not saying that life needs an otherworldly miracle to begin, or that science isn’t making progress in refining possible scenarios. Rather, the evidence needed to scientifically know what happened on early Earth is gone, erased by 4.5 billion years of turbulent geology and changing atmospheres, and some 3.8 billion years of evolution.
So starting life is, by most accounts, the biggest deal. Keeping it going and allowing it to evolve is also a big deal, and is where the “Rare Earthers” find disqualifying obstacles. So many stellar, solar, and planetary factors have to be just so for evolution to produce complex life that the chances of it happening frequently are slim to none, they argue. They might be right. But this presumed specialness of the cosmic dynamics that allowed Earth and perhaps only Earth to be stable long enough for single-cell life to evolve into something more complex sounds familiar, suspicious even. Earth was special, too, when people believed it was the center of the universe, and it is unique today to those who reject the logic and power of evolution and natural selection as a pathway from simplicity to complexity. Ward and Brownlee certainly don’t share those beliefs, but they are awfully impatient. Given the fact that we have known for sure only since 1995 that planets exist outside our solar system, and given the fact that talented and engaged scientists strongly believe that innumerable stars have habitable zones for the planets that orbit them, and given the fact that the laws of physics and chemistry appear to work throughout the universe as they do here, it seems very premature to say that complex life evolved on Earth alone. Especially so, now that respected astronomers like Geoff Marcy and Andrew Howard have extrapolated from their planet-hunting data that tens of billions of Earth-sized planets exist in the Milky Way alone.
What’s more, as any microbiologist will tell you, single-cell organisms come in species from the rudimentary to the extremely complex, they contain the same kind of DNA-based genetic material that organizes the rest of “higher” life, and they ruled the Earth alone for most—more than 75 percent—of the time that Earth has supported life. So if microbes are common across the universe, then it strains credulity to conclude that evolution everywhere else stops with them. Certainly, single-cell life on other distant planets can be easily snuffed out by an incoming asteroid, a fading sun, or any number of other catastrophes. But if astrobiology has proven nothing else, it has unequivocally shown that life, once started, is tenacious beyond imagination, and that it can adapt to the most extreme circumstances.
OPTION 3. Life exists beyond Earth and, in some instances, has become complex and most likely includes what we would consider intelligence.
Not surprisingly, this is what many and probably most scientists involved in astrobiology consider the most likely scenario. An objection often raised to this conclusion is that if extraterrestrial life existed on other planets or moons, we would have already found it. Similarly, people ask, if intelligent alien life exists, why hasn’t it come to Earth and made itself known? Variations on these questions were famously posed by nuclear physicist Enrico Fermi in 1950: If the perceived probability of the existence of extraterrestrial civilizations is so high, he asked, then why is there no evidence for, or contact with, any life-forms beyond Earth? Fermi’s paradox is not an insignificant obstacle. It was posited around the time that UFO reports—perhaps the layman’s answer to the paradox—became the rage. Absent a good answer, some people turned to a bad one. But other answers exist, and many again focus on the vastness of time and space.
Humans have had the capacity to actually search for extraterrestrial life in a technologically advanced way for only about fifty years. We on Earth have produced radio waves and other far-traveling signatures of intelligent activity for less than 150 years. In a universe estimated to be 13.8 billion years old, and which has had stars, solar systems, and trillions of planets for a good portion of that time, 150 years is not even a blink of the eye. What’s more, the stars closest to our sun are the Alpha Centauri system, about 4.25 light-years away. That’s about 30 trillion miles. No planets have actually been found in Alpha Centauri, but let’s assume for a second they exist and house intelligent life. Traveling at the speed of light, a beamed message going back and forth to our solar system would take 8.5 years.
It’s true that the biosignatures of atmospheric oxygen and complex hydrocarbons have been around Earth’s atmosphere much longer, and technologically advanced civilizations from beyond could have detected them and known what they meant. Logic says that is correct, but doesn’t offer much more on the question. But science, and especially astrobiology, is grounded in this different truth: An absence of evidence is not evidence of absence—unless you’re looking for living brontosauri or unicorns in the ballfield. It may be meaningful or frustrating to some that extraterrestrial life remains unfound or unconfirmed but, really, the search has just begun. When Fermi posed his paradox, it actually hadn’t even begun. Step back a bit, and this picture emerges of what has been discovered: The universe is now ruled by what appears to be a singular set of laws of physics and chemistry, organizing principles that led to the formation of single-cell microbes on one planet at least and, through evolution, led to ragweed, cats, and us. The universe is now known to be swimming in carbon, amino acids, nitrogen, hydrocarbons, water, and energy from starlight—the bottom-line essentials for life as we know it. And life on Earth has shown itself to be extraordinarily tenacious and capable of surviving catastrophes from asteroid hits to the glacial times of what is sometimes called Snowball Earth. If life started on any of those countless other planets we know to be out there, why wouldn’t it have the same tenacity? The universe, it seems, has the ingredients and structure for quite a cosmic menagerie.
Yes, spacecraft have landed on or flown past most of the planets and some of the moons of our solar system, and no life has yet been confirmed. What’s more, we’ve found that conditions out there can get awfully cold, awfully hot, awfully dry, and awash in killing cosmic radiation. But many planetary scientists hold that the possibility of some current or former life on Mars, Europa, or Enceladus in particular remains very much intact, and our ability to identify and confirm its presence is in its infancy. Any discovery of a second or third genesis in our own pedestrian solar system would pretty much have to mean that life is a commonplace across the universe. So the real long-term action is those exoplanets, the ones we’ll be examining with occulters and sunshades and spectrometers on the lookout for signatures of life. Doesn’t it seem unlikely that none—zero—of the trillions and trillions of planets now reasonably presumed to exist beyond our solar system have the ingredients and conditions needed to cobble together life, and the stability needed to allow
life to evolve and grow more complex? Doesn’t it seem more likely that we will, in the near or further future, make our first contact with undoubtedly extraterrestrial life, and that it will be a day our world long remembers as the harbinger of a new frontier in a dramatically changed cosmos?
ACKNOWLEDGMENTS
My indebtedness to the insights, skills, and kindnesses of others in creating this book is perhaps best told through chronology. It was due to a series of hardly inevitable occurrences that the project was started and through the generosity of others’ spirit that it grew and thrived.
It was my Washington Post colleague Shankar Vedantam who got the ball rolling. He had participated in the Templeton-Cambridge Journalism Fellowship in Science and Religion at Cambridge University, and for several years he suggested I, too, might find it valuable and enjoyable. My resistance broke down in 2007, and I’ll be forever grateful to Shankar for his persistence. My month at Cambridge in 2008 was spent listening to talks by prominent and often compelling speakers from many disciplines, and then was followed by my writing and presenting a paper on the topic I had selected—astrobiology and its implications for religion. The Cambridge program was expertly run with great hospitality by Fraser N. Watts, Director of the Psychology and Religion Research Group at Cambridge University and an Anglican priest; Julia Vitullo-Martin, director of the Center for Urban Innovation in New York; and Sir Brian Heap, a research associate at the University of Cambridge. Their help and encouragement was essential, and the fellowship provided an ideology-free setting for learning.
