Science has shown it's no longer a question of "do aliens exist?" but rather "when will we contact them?"
The Aliens Are Coming!: The Extraordinary Science Behind Our Search for Life in the Universe (The Experiment, 2016) by Ben Miller is a refreshenigly clear, hugely entertaining guide to the search for alien life. Ben Miller-Cambridge-trained quantum physicist, bestselling science writer, and popular comedic actor-looks everywhere for insight, from the Big Bang's sea of energy that somehow became living matter, to the equations that tell us Earth is not so rare, to the clues bacteria hold to how life started.
On August 25, 2012, the first of our ships reached interstellar space. It was unmanned. Launched three and a half decades earlier, it had skirted Jupiter and Saturn, and was now heading out of the solar system toward Camelopardalis, a little-known constellation close to the Big Dipper. Although clear of the solar wind, it was not quite out of reach of the sun’s gravity, nor would it be for a further thirty millennia. By then it would finally have traversed what is known as the Oort Cloud, a thick outer shell of icy rubble that encases our home star and its eight planets like the flesh around a peach stone. At that point it would be nearly a light-year out. Forget the galaxy; even the solar system is unimaginably large.
The ship’s name was Voyager 1, and on board was a message from the people of Earth, encoded on what became known as the “Golden Record.” This gold-plated phonographic disc, curated by the distinguished American cosmologist Carl Sagan, spoke on behalf of all humanity. It began with a recorded message from the Secretary-General of the United Nations, Kurt Waldheim. Reading haltingly, with a strong Austrian accent, he made the following statement:
I send greetings on behalf of the people of our planet. We step out of our solar system into the universe seeking only peace and friendship: to teach if we are called upon; to be taught if we are fortunate. We know full well that our planet and all its inhabitants are but a small part of this immense universe that surrounds us and it is with humility and hope that we take this step.
After this greeting came a choir of voices speaking in fifty-five languages:* everything from Akkadian, the language of ancient Sumer, to Wu, the contemporary Chinese dialect spoken around Shanghai. Some, such as the Japanese, appeared shy: “Hello, how are you?” Others were more forthcoming, such as the Amoy of southeastern China, who offered: “Friends of space, how are you all? Have you eaten yet? Come visit us if you have time.” The speaker of Ancient Greek, on the other hand, issued a barely concealed threat: “Greetings to you all, whoever you are. We come in friendship . . . to those who are friends.”
These Greetings of Earth were accompanied by twenty-odd Sounds of Earth, among them echoing footsteps, hard rain, and a handsaw cutting fresh wood. Over one hundred Scenes of Earth showed images such as a hand being x-rayed, the chemical structure of DNA, and a man and a pregnant woman in silhouette. And, finally, there was the Music of Earth, with over twenty of humanity’s nest recordings, including the first movement of Beethoven’s Fifth, Bach’s Well-Tempered Clavier, and “Johnny B. Goode” performed by Chuck Berry.
That might have the flavor of science fiction—at least, I hope it does as I was trying my hardest—but it is all true. So far as we know, the Golden Record has not yet been intercepted by spacefaring aliens. If it is, what they are to make of it is any- one’s guess. For a start, we have to hope that they aren’t too big. An alien the size of a blue whale might have a hard time getting a needle in the groove, let alone building a hi- system for it to play on at the required speed of 162/3 revolutions per minute. Equally, too small an alien—one the size of a microbe, say—might never realize the Golden Record, or Voyager 1 itself, was even there in the first place.
Next, of course, we have to hope that they share our perception of time. As we shall see in a later chapter, not all animals on Earth do, let alone all aliens. To crows, for example, whose brains have a faster clock, human communication appears slow and deliberate. If “alien time” passes much faster than “human time,” the aliens might not realize that human speech contains information; it might simply sound like long, unintelligible groans. To understand human speech, it helps to have a brain that chugs along at human speed.
And while we are on the subject of human speech, we had better hope that any aliens that find the Golden Record have ears, that the frequency range of those ears matches that of our own, and that they themselves communicate using vocalizations. On a deeper level, we had better hope that the concepts expressed in our messages—things like “peace” and “space” and “time”—have equivalents within their own language, or languages. And on an even deeper level, we hope they share the concept of a “message” within their culture, and don’t just re it straight back again.
It doesn’t end there. To be able to see the instructions on the case of the Golden Record, detailing how the information inside is to be decoded, the aliens had better be able to see, and their vision had better be attuned to the same range of the electromagnetic spectrum as our own eyes. Again, we can see from life-forms on Earth that this is not a given. A race of superintelligent bats, for example, might see the Golden Record as nothing more than a metallic Frisbee. A community of superintelligent bacteria might just see it as a snack.
And, most importantly of all, we had better hope that the aliens have a good understanding of human culture. If they don’t, they are going to have a hard time figuring out what we were up to. When storage capacity must have been so precious, why include so many greetings? Why are genitals shown in some of the drawings of humans, but not in others? What’s the music for? Who are these people, and what the hell are they trying to tell us?
In short, we had better hope that the aliens are just like us.
Is there any question more fascinating than whether or not we are alone in the universe? The faint, ghostly light of the Milky Way is the glow of billions of stars. Is it really possible that Earth is the only habitable planet among them, and that we are the only intelligent species? And if there is intelligent life out there, might we be able to communicate with it?
The Ancient Greeks certainly thought we might. Epicurus, for example, one of the founding fathers of modern science, stated around 300 BC that “other worlds, with plants and other living things, some of them similar and some of them different from ours, must exist.” Newton was also onside, as is plain from an appendix he added to his famous treatise on mechanics and gravitation, the Principia:
This most beautiful System of the Sun, Planets, and Comets, could only proceed from the counsel and dominion of an intelligent and powerful being. And if the fixed Stars are the centers of other like systems, these, being form’d by the like wise counsel, must be all subject to the dominion of One.
Aliens are everywhere. They can be angels come to warn us of the follies of nuclear war or they can be demons that abduct us to carry out bizarre sexual experiments. Their shape changes, from the angry Little Green Men of the first half of the twentieth century to the placid Greys of the present day. They visit us in flying saucers, speak to us telepathically, or appear as strange lights in the sky. Yet so far as we can determine, all this is a product of our imaginations. Much as we might wish it were otherwise, there is no compelling evidence that intelligent, technologically advanced aliens have ever visited Earth. But before you throw this book down in a pique of anti-scientific disgust and head for the Mind, Body, and Spirit section, stop. Because as is so often the case, the real science is so much more interesting than the non-scientific stuff. While alien autopsies grab the headlines, thousands of scientists— real, hardworking, peer-reviewed, genuinely qualified scientists—are slowly inching closer to the real thing. And trust me: If we do manage to make contact with an alien intelligence, those stories about flying saucers and pervy Little Green Men are going to seem very man-made indeed.
The plain truth is that the last few years have seen something of a sea change in the way we view life in the cosmos. Thanks to NASA’s recent Kepler mission, we have discovered that planets like ours are common throughout the galaxy. We also know that life got started on Earth very early in its history, and that it thrives in some incredibly extreme environments. As our probes and manned missions venture out into the solar system, and we image Earthlike planets with ever-increasing accuracy, our first encounter with alien life is rapidly approaching.
Most scientists expect that encounter will take place via a telescope, and that the life in question will be in the form of single-celled organisms so small that they would be invisible to the naked eye. A second, slightly more remote possibility is that microscopic organisms will be found on an icy moon within our own solar system, or even living cheek by jowl with us right here on Earth. And if single-celled life is as widespread as we currently believe, complex intelligent life won’t be far behind.* Just how far behind is the subject of this book.
Thrillingly, it turns out that life on Earth can teach us a surprising amount about life on other planets. Complex life, as we shall see, is rarer than single-celled life; exactly how much rarer is a subject of an intense but increasingly well-informed debate. Intelligence, as we shall shortly discover, is not unique to humans; in fact we share it with at least half a dozen other species, and maybe more. Some of those other intelligent species even have language, and decoding it may be an important first step toward communicating with extraterrestrials.
Forget science fiction. You are living through one of the most extraordinary revolutions in the history of science, the emergent belief of a generation of physicists, biologists, and chemists that we are not alone. Our journey to understand how this revolution has come about will lead us through some ravishingly beautiful science, and hint at answers to some truly deep existential questions. All of what follows is accessible if you have an open mind; in fact, a creative bent will be as valuable as a scientific one, because this subject goes right to the heart of what it means to be human.
Before we get started, here’s the briefest of guides to the journey ahead. These three opening chapters will give us an overview of the hunt for extraterrestrials to date, UFO crazes included, and try to answer the question of why the Search for Extraterrestrial Intelligence, or SETI as it is known, has gone from pariah to pontiff in less than a decade. In the meat of the book, we’ll get a handle on what our latest studies of life on Earth can tell us about the possibilities for “life-as-we-know-it” and “life-as-we-don’t”—in other words, the chances of finding intelligent extraterrestrial organisms that are based on car- bon, and those made of something else entirely. Finally, we’ll look at how we might decode an alien message, should we be lucky enough to receive one, and what kind of messages—if any—we should be sending in return.
If our science is right, within the next decade we will have hard evidence that there are other living things out there in the universe. As we shall see, it’s an outside bet, but if we are very lucky, some of those living things will have been just at the right stage of development at just the right time to have sent us a message that we are capable of understanding. Some of those messages might be traveling through you right now, as you read this book. If you are at all interested in how we might intercept them, and what they might say, read on . . .
Excerpted from The Aliens Are Coming! by Ben Miller. Reprinted by permission of the publisher, The Experiment.