Light of the Stars Read online

  OTHER BOOKS BY ADAM FRANK

  Astronomy:

  At Play in the Cosmos

  The Constant Fire:

  Beyond the Science vs. Religion Debate

  About Time:

  Cosmology and Culture at the Twilight of the Big Bang

  To my sister, Elisabeth Frank, and our long, strange road. I am grateful that your humor, resolve, and Camp Dawson friendship were on this path with me.

  CONTENTS

  INTRODUCTION: THE PROJECT AND THE PLANET

  CHAPTER 1: THE ALIEN EQUATION

  CHAPTER 2: WHAT THE ROBOT AMBASSADORS SAY

  CHAPTER 3: THE MASKS OF EARTH

  CHAPTER 4: WORLDS BEYOND MEASURE

  CHAPTER 5: THE FINAL FACTOR

  CHAPTER 6: THE AWAKENED WORLDS

  ACKNOWLEDGMENTS

  NOTES

  ILLUSTRATION CREDITS

  INDEX

  LIGHT OF THE STARS

  INTRODUCTION

  THE PROJECT AND THE PLANET

  THE COSMIC TEENAGER

  Imagine a room full of teenagers. The chairs are arranged in a loose circle, and the air smells of cheap cleaning products and anxiety. The kids are mostly in their late teens. Some are slumped in their chairs, trying to look bored; others lean forward, listening closely. They are here to tell their stories. The sixteen-year-old girl in the Black Sabbath T-shirt and chipped black nail polish got busted for dealing drugs at her high school. The skinny boy with a bad tattoo on his hand was arrested for joyriding in his grandparents’ car. They’re all in this room because they’re on the wrong road. Old enough to have some power over their own lives, they’ve been making bad choices, destructive choices.

  Each of the kids takes a turn unspooling how they got here. Some came from families that could barely hold it together. Others were trapped in their own feelings of isolation and insecurity. But in telling their stories, some of the kids catch a glimpse of an insight. It’s something they couldn’t imagine, couldn’t truly feel, before.

  They are not alone. They are not the first.

  The circle and the stories give some of the kids the chance to see that it’s not just them. Their individual stories are not so individual. Other kids their age have walked this road before, and some have even found a way out. Some have found a way to grow up.

  • • •

  WE HUMANS, with our project of civilization, are like those kids.

  The massive collective project we call civilization began about almost ten thousand years ago, when the last ice age ended and our planet’s climate grew warmer and wetter. In response, some of us stopped our nomadic wandering and settled into villages. Around those small groupings of huts and storehouses, the Earth was put to plow. We cultivated grains and rice. We domesticated the ox, the goat, and the cow. We created a new way of being human beyond the old hunter-gatherer way of life. It was an agricultural revolution that brought with it a radically different way of understanding ourselves and our place beneath the stars. This project of civilization accelerated when some of the villages grew into the first cities. There, we developed sophisticated new technologies for irrigation. We forged metals and stored information in writing. Through the tumult of markets and trade and conflict, our work became specialized. Some of us became millers, others tanners, others soldiers, and others still administrators. Some of us even became a special kind of priest whose job it was to watch the skies. And all the while, our numbers steadily increased. By one thousand years after the birth of Christ (1000 CE), three hundred million human beings walked the Earth.1 Then, just five or six centuries ago, a new approach to the natural world was established. Harvesting ideas from across the planet, we discovered a method for directly probing the world’s behavior—what we now call science. Using it, our project’s capacities exploded. We learned to cross oceans quickly in ever-larger ships and in relative safely. Improvements in sanitation and medicines began to keep us from dying young. Machines for farming began freeing us from famine. In response, population growth rates exploded, and in the first half of the 1800s, our numbers crossed the one billion mark.2

  In the years around that milestone, we made perhaps the most important discovery for our project of civilization. Using the fruits of our newly established scientific society, we learned how to harvest fossil fuels. Tapping a hundred million years of stored sunlight in the form of coal, and then petroleum,3 industrial civilization tidal-waved across the globe. Touching even the most remote corners of every continent and every ocean, our capacities seemed to grow without limit. By 2011 CE, just about two centuries after reaching one billion, our numbers had climbed to seven billion.4 Today, even a modest-sized modern city houses more people than lived on the entire planet before the dawn of agriculture. Using the tools of science and its daughter technologies, we explored the entire planet. We mapped everywhere. We were everywhere. These days, at any given moment, there are even half a million people flying miles above the ground.5

  Our project was thriving.

  For the most part, the planet took little notice of our experiment in civilization building. The clearing of land for farming certainly altered local balances of life and resources, but the Earth as a whole—meaning the surface, air, water, and life—wasn’t significantly and globally disturbed from the state we found it in when civilization began. With the industrial revolution in the 1800s, the relationship between the project and the planet shifted. Earth began to “feel” our presence. Air, water, ice, rock—all the interdependent, strongly linked parts of the planet we inhabit—began to change. And, as it has done many times before in its four-and-a-half-billion-year history, the Earth started shifting from one planetary “state” to another.

  The relatively temperate planet our project of civilization was born into began sliding into the past. Something new, something as yet unknown, now waits for its own time to begin. The planet is changing, and it’s changing because of us. Those changes will, without doubt, stress our project of civilization. If the changes are extreme enough, they may even make the kind of civilization we rely on for survival impossible to continue. Our project may collapse.

  And that is why humans, with our project of civilization, are cosmic teenagers (as Carl Sagan often noted). Our technology and the vast energies it has unleashed give us enormous power over ourselves and the world around us. It’s like we’ve been given the keys to the planet. Now we’re ready to drive it off a cliff. Unlike those kids, however, we are still blind to the truth. We are still unable to see the reality our project of civilization only recently revealed.

  We are not alone. We are not the first.

  Across our history, we have never seen our project of civilization—or ourselves, for that matter—as anything but a one-time story. We have always appeared to ourselves as something essentially new, something entirely different. Every step we humans took was a step into the unknown. There was nothing to guide us, no other histories we could look to and know what might be expected.

  It is time to put that story to rest, because we have grown past it.

  Through long effort, we have mapped out the four-billion-year history of life on Earth, and it shows us that we are not the first. We are not the first time a species has changed a planet’s climate through its own success. The Earth and its inhabitants have been evolving together for eons, and we are just the most recent in a long line of its experiments.

  But there is more.

  Our science has also shown us something we did not know even twenty years ago. The universe is awash in planets and they are, in principle, not so different from our own. There is every reason to expect that on many of these worlds there will be oceans and currents. There will be mountains with fierce winds and valleys that begin the day shroude
d in morning fog and end it with falling rain.

  And there will be life, too. Sure, it is possible we’re on the only world to host life in all of cosmic history. Science has, of course, been arguing about the existence of life on other worlds for centuries. But the explosion in our knowledge about other worlds sheds new light on this question, revealing something remarkable. The discovery of all those new planets means we can only be unique if the laws of the universe are strongly biased against life and intelligence. In other words, there are so many planets in the right place for life to form that the burden now falls on the pessimists. It’s up to the naysayers to demonstrate how, with so many worlds and so many possibilities over the whole of cosmic space and time, we somehow are the first and the only.

  So, while it is important to remember that the question of other life on other worlds remains open and undecided, we can now see that there has, most likely, been life before us. And on some worlds that life will, most likely, build rich and complex biospheres. Going further still, over the long history of the cosmos, life on some of those other worlds will, most likely, have woken up. It will have learned to think, to reason, and even to build its own projects of civilization.

  One way or another, science points to the fact that we are likely not the first. Now it’s time to take those insights from astronomy and earth science seriously. In light of our maturing knowledge, it’s time to tell a different story about ourselves and our fate among the stars and their many worlds.

  SCIENCE AND MYTH

  Try to get a teenager to change his or her driving behavior only by quoting statistics about traffic fatalities, and you’re likely to be met with a blank stare. That’s because we humans need more than numbers or the rising curve on a graph to understand the world. We are fundamentally storytellers. Ask the kids in that group of troubled teens about themselves, and they’ll respond with a narrative about families and fights, their isolation at school, or the time they ran away or the day a parent skipped out on them. We all use stories to make sense of ourselves in the world. And what’s true of individuals is also true of cultures and the sweep of their history.

  For most of history, we have used myth to tell our biggest stories. When you hear the word myth, you’re likely to think of a false story. But, taking a long view of human evolution, myths are often more than just true or false, and they’ve always played an essential role for us. Every society, in every time and place, has had a system of myths, a constellation of stories that provide a basic sense of meaning and context. Some speak only to our internal life as we make our transitions to adulthood, to parenthood, and to old age. But some tell the big stories. Through these mythic-scale big stories (including their forms in religion), people came to understand how their culture thought the universe was born, how the Earth was formed, and how people were made.

  In our age, that role falls to science. Instead of gods and spirits, we now have the Big Bang and Darwin’s story of the descent of man. With science, we found a new way to enter into a dialogue with the world, one where experimentation and evidence led the way. That’s how the big stories get put together for us moderns. But the power of those stories as stories never went away.

  When it comes to the fate of our civilization in a climate-changed world, however, we don’t have a big story that can convert rising global temperatures and melting Greenland ice sheets into a grand narrative with us in it. The only thing close is a story that goes something along the lines of “we suck.” Human beings are greedy and selfish. We are nothing but a plague on the planet.

  That story is not only unhelpful and impoverished, it’s also entirely wrong from the perspective of the new understanding of life and planets we’ve recently gained. People often cast the climate crisis in terms of “saving the planet.” But as the biologist Lynn Margulis once put it, the Earth “is a tough bitch.”6 It’s not the Earth that needs saving. Instead, it’s us and our project of civilization that need a new direction. If we fail to make it across the difficult terrain we face, the planet will just move on without us, generating new species in the novel climate states it evolves. The “we suck” narrative makes us villains in a story that, ultimately, has none. What that story does have are experiments—the ones that failed and the ones that succeeded.

  This larger perspective, gained in light of the stars, does not absolve those who drive climate denial for reasons of greed or political gain. They are fully culpable for their folly. From a planetary perspective and its long view, they will become the reason why Earth’s experiment in civilization building fails to reach its higher potential.

  So there is an entirely new “big story” we can tell. It’s a drama that puts humanity back into the life of the planet. It’s a narrative that puts Earth and its life back into the proper context of a universe awash in planets.

  In this new story, we aren’t collectively villains but we may collectively become losers.

  ASTROBIOLOGY AND THE ANTHROPOCENE

  Over the last half century, our project of civilization has learned to look out and look back as never before. We have looked back billions of years to uncover the Earth’s deep history. We’ve seen how our species and its civilization comprise just another “expression of the planet,” as writer Kim Stanley Robinson calls it.7

  The evolution of the planet and its life cannot be separated. That is what our science has shown us. Earth and its life must be thought of as a whole that “coevolves” together. Two and a half billion years ago, for example, it was microbes that reworked the world by creating the oxygen-rich atmosphere we now breathe. In the process, those species “polluted” themselves off most of the planet’s surface.8 Using this new oxygen-rich air, the Earth then moved on to create new versions of itself, like the one with the first large sea-creatures, the one with enormous dinosaurs, and the one carpeted by vast grasslands. Those fish, dinosaurs, and grasslands were once new actors on the world’s stage. They appeared and took their places in the long drama of Earth’s undirected experiments in coevolution. The Earth has run many experiments in life and its possibilities over the last four billion years. We’re just the latest version, and in that way we’re not so unique.

  And just as our science looked back to reveal Earth’s history, it also looked outward, traveling across billions of miles to explore the other worlds of our solar system. These audacious journeys showed us that “climate” is not something limited to patterns in your local weather report. On Venus, 220-mile-per-hour winds blow high in the atmosphere.9 On Mars, icy fog forms each night near its northern pole.10 There’s even rain (made of gasoline) drifting over forty-mile-wide lakes on Titan, the giant moon of Saturn.11 In terms of having a climate, our planet is also not that unusual.

  Finally, we have also looked out to the stars and discovered that the universe is fecund with solar systems like our own. The numbers from these monumental studies tell us that projects of civilization like ours may likely have occurred elsewhere at other points in cosmic history. As long as the universe isn’t exceptionally biased against it, we are not the first. Others, on other worlds, will likely have come before us. And with our new knowledge of planets and their laws, we can also see that they too will likely have faced a similar dilemma to the one staring us down today. Even our climate crisis may likely not be so unique and not even that unusual.

  So our science has done its job. When it comes to the relationship between life and planets, it has shown us entirely new realities and new possibilities. This science is new, it’s revolutionary, and it’s called astrobiology. Through the truly heroic efforts of scientists across the world, astrobiology has opened up new, universal truths for us about the braided potential for planets and life. It has shown us what has happened here, and what might happen elsewhere.

  That knowledge comes at a strangely auspicious moment, bestowing it with great consequence.

  Ten thousand years ago, our project of civilization was born after the beginning of what geologists call the Holocene, a p
lanetary epoch of warm, wet conditions following the end of the ice ages. But in driving climate change, we’re now pushing the Earth out of the Holocene into a new era in which human impacts dominate the planet’s long-term behavior. The new era is called the Anthropocene.12

  We all want our project of civilization to continue deep into the Anthropocene. But our efforts so far have mostly failed. We’ve known about global warming, the most obvious symptom of the emerging Anthropocene, for more than fifty years.13 Despite having that knowledge, we’ve done almost nothing to deal with climate change and its consequences. Our politics, our economics, and even our moral philosophy have all failed to drive actions that could ensure the long-term sustainability of our project on a changing planet.

  That failure is rooted in the mistaken view that we, and our project, are a one-time story. But we can be forgiven for that failure because, until very recently, we didn’t have the tools or the information to rise above such tunnel vision. We did not yet have the astrobiological perspective. But now we do, and it can change the path to our future.

  This book explores what might be called the astrobiology of the Anthropocene, and it’s built out of two braided questions.

  •What can the revolutions of astrobiology tell us about life on other worlds, even other intelligences and their civilizations?

  •What can life on other worlds, even other intelligences and their civilizations, tell us about our own fate?

  These interwoven questions will lead us to a fundamentally new story about what we are and what’s happening to us at this crucial moment in our civilization building. It’s a narrative built from space telescopes, deep-sea submersibles, robots diving into comets and geologists scrambling over deadly glacial chasms. In telling that story we’ll encounter science that is nothing less than thrilling.