Alien Nations: Why Life on Other Planets Will Resemble Ours

Hard science offers a remarkably detailed portrait of how extraterrestrials may live — and clues on where our own civilization is headed

Scientists, now routinely detecting potentially habitable planets in space, are the closest yet to determining the truth about aliens. But there is another question that almost none talk about: If other beings do populate the universe, what are they doing out there?

Are the possible inhabitants of Teegarden b, some 12 light-years from Earth’s solar system, driven to explore and migrate? Do they have a great power rivalry with the citizens of Teegarden c? What about the potential folks on the “super Earth” exoplanet K2–72 e? Are they inclined to hate and love according to tribe?

Such questions may appear to be only the stuff of science fiction. But it turns out that the hard laws of physics, biology, and geophysics apply on other habitable planets just as they do on Earth. And they suggest a remarkable level of detail about how alien societies might operate, says the astrophysicist Frank Drake, detail that among other things could help resolve some of humankind’s most charged debates, from how to confront a changing climate to how to treat beings from other places.

Drake is the man behind the Drake equation, the intellectual foundation of the six-decade-old effort to find technologically advanced alien life. At 89, he is still one of the most respected figures in space science. The search for aliens has turned up nothing thus far, but Drake says he has at least some idea of what space societies will look like. “In many, many places, evolution would produce intelligent species capable of making things,” he said, sitting in front of a mug of coffee in his California home, up the road from the beach amid millennium-old redwoods near Santa Cruz. “They will make technology we could detect from a great distance. That will be a common event. They will first make [primitive machines] and eventually radar transmitters, and once they make a radar transmitter, we can discover them.” Drake barely blinked.

Science cannot tell you the precise social details of an alien society — is there democracy? Do otherworldly beings go through courtship? But the principles governing atoms, chemistry, and fundamental forces everywhere can be used to infer its broad shape. If there are technological societies in space, for instance, the extraterrestrial population almost certainly lives in cities and uses language, since such cooperation underpins civilizations. Given that legislatures, iPhones, and Simone Bileses do not arrive from nowhere, its population is the beneficiary of competition and cooperation. There would have to be politics and war, since that is how disputes are resolved. There would be a locus of power in the form of leadership. That leader — a monarch, a parliament, a president, whatever — would be tribal and territorial, since a society is a coherent group with boundaries, even if there are divisions within it, according to Nicholas Wright, a neuroscientist at University College London.

Hence Drake’s eponymous equation, the more or less standard formula for estimating the number of technological space civilizations, and his lifelong search for the radio or light signals that he is certain aliens are transmitting, as if shouting to Earth, “We are here.”

The Drake equation consists of seven variables involving the state of the universe that, when multiplied, assume the answer to one of the universe’s great mysteries: Are we alone? We are not, Drake responds, and with his equation goes on to attempt to calculate just how many technological societies are out there. In 1950, that question was the subject of one of the most consequential lunches in the history of space science. The Nobel Prize-winning physicist Enrico Fermi was dining with other science luminaries at Los Alamos, the national laboratory in New Mexico where the atomic bomb was invented, when he uttered three words that have haunted alien hunters ever since: “Where is everybody?” That is, if there are so many technologically able extraterrestrials, as many scientists thought even before Drake, why had no one yet seen one? The question became known as Fermi’s paradox.

When Drake proposed his equation in 1961, he was not responding directly to Fermi’s question — Drake’s calculation tells nothing about the location of aliens. Instead, Drake, then a young astronomer at Green Bank Observatory in West Virginia, was trying to devise an organizing principle for a meeting of scientists that he had been asked to host. On the agenda was determining a strategy to detect signals of alien life using a radio telescope, and so Drake — figuring that for starters the scientists needed to grasp the sheer difficulty of their task, meaning the number of space civilizations that might exist — formulated what would thereafter be called the Drake equation.

Despite the exoplanet revolution, there has been no conclusive sign of alien life, which means Fermi’s question persists: “Where is everybody?”

The meeting quickly became space lore, and launched a formal alien hunting initiative called the Search for Extraterrestrial Intelligence, or SETI for short. The meeting’s attendees would dub themselves the “Order of the Dolphin,” after discussions they held about communication among species here on Earth, and NASA would spend about $78 million on the quest over the subsequent years. Drake himself became among the field’s biggest celebrities. From the appearance of bacteria to intelligent humans discovering fire and electricity, a compact synthesis of science and history on Earth told him that alien voices could be found if we just listened hard and long enough. “To me, it seemed that a particular course of growth should happen often out there,” Drake said. “There should be something there to find. That’s the whole story in a nutshell.”

As straightforward as the equation seems written in full, it turned out that neither Drake nor the rest of the SETI field could assign a confident numerical value to any but the very first of the variables — the rate of star creation. They could not even be sure how many stars hosted planets, another key Drake variable. For more than three decades afterward, no one got any further. Federal funding for SETI research dried up, cut off by Washington politicians who said it was a waste of money.

But in 1995, a Swiss astronomy PhD candidate named Didier Queloz, working with his professor, Michel Mayor, at the Haute-Provence Observatory in southern France, made a blockbuster discovery. Monitoring the light from a star called 51 Pegasi, 50 light-years from Earth, Queloz detected a wobble that suggested the presence of a nearby, smaller body, such as a planet. For six months, they checked and rechecked their observations, then made an announcement: They had found the first clear evidence of a planet orbiting a sun-like star outside the solar system — what’s known as an “exoplanet.” It marked the start of a scientific revolution — the first actual proof that there were in fact places where aliens might live. Last year, Queloz and Mayor shared the Nobel Prize in physics for their work.