Winston Churchill, British prime minister and one of history’s most influential statesmen, was undoubtedly a man with weighty questions on his mind. How best to save the British Empire? he must have mused. What will the postwar world look like? he surely wondered. But the legendary leader also focused his prodigious mind on less pragmatic questions. For instance: Is there life on other planets?
In fact, in 1939, Churchill penned a lengthy essay on this very topic, which was never published. Besides displaying a strong grasp of contemporary astrophysics and a scientific mind, he came to a breathtaking conclusion: We are probably not alone in the universe. The long-lost piece of Churchilliana has just floated up to the surface again, thanks to an article written by astrophysicist Mario Livio in this week's edition of the journal Nature analyzing Churchill's work.
“With hundreds of thousands of nebulae, each containing thousands of millions of suns, the odds are enormous that there must be immense numbers which possess planets whose circumstances would not render life impossible,” Churchill concluded in his essay. He wrote these words on the eve of World War II—more than half a century before exoplanets were discovered.
Until last year, Churchill's thoughts on the problem of alien life had been all but lost to history. The reason: His 11-page typed draft was never published. Sometime in the late 1950s, Churchill revised the essay while visiting the seaside villa of publisher Emery Reves, but the text still didn't see the light of day. It appears to have languished in the Reves house until Emery's wife Wendy gave it to the U.S. National Churchill Museum during the 1980s.
Last year, the museum’s new director, Timothy Riley, unearthed the essay in the museum's archives. When astrophysicist Mario Livio happened to visit the museum, Riley "thrust [the] typewritten essay" into his hands, Livio writes in Nature. Riley was eager to hear the perspective of an astrophysicist. And Livio, for his part, was floored. “Imagine my thrill that I may be the first scientist to examine this essay,” he writes in Nature.
Churchill did his homework, Livio reports. Though he probably didn't pore over peer-reviewed scientific literature, the statesman seems to have read enough, and spoke with enough top scientists—including the physicist Frederick Lindemann, his friend and later his official scientific adviser—to have had a strong grasp of the major theories and ideas of his time. But that wasn't what left the deepest impression on Livio.
“To me the most impressive part of the essay—other than the fact that he was interested in it at all, which is pretty remarkable—is really the way that he thinks,” Livio says. “He approached the problem just as a scientist today would. To answer his question 'Are we alone in the universe?' he started by defining life. Then he said, 'OK, what does life require? What are the necessary conditions for life to exist?'”
Churchill identified liquid water, for example, as a primary requirement. While he acknowledged the possibility that forms of life could exist dependent on some other liquid, he concluded that “nothing in our present knowledge entitles us to make such an assumption.”
"This is exactly what we still do today: Try to find life by following the water,” Livio says. “But next, Churchill asked 'What does it take for liquid water to be there?' And so he identified this thing that today we call the habitable zone.”
By breaking down the challenge into its component parts, Churchill ended up delving into the factors necessary to create what is now known as the “Goldilocks zone” around a star: that elusive region in which a life-sustaining planet could theoretically exist. In our own solar system, he concluded, only Mars and Venus could possibly harbor life outside of Earth. The other planets don't have the right temperatures, Churchill noted, while the Moon and asteroids lack sufficient gravity to trap gasses and sustain atmospheres.
Turning his gaze beyond our own solar system raised even more possibilities for life, at least in Churchill's mind. “The sun is merely one star in our galaxy, which contains several thousand millions of others,” he wrote. Planetary formation would be rather rare around those stars, he admitted, drawing on a then-popular theory of noted physicist and astronomer James Jeans. But what if that theory turned out to be incorrect? (In fact, it has now been disproven.)
“That's what I find really fascinating,” Livio notes. “The healthy skepticism that he displayed is remarkable.”
Churchill suggested that different planetary formation theories may mean that many such planets may exist which “will be the right size to keep on their surface water and possibly an atmosphere of some sort.” Of that group, some may also be “at the proper distance from their parent sun to maintain a suitable temperature.”
The statesman even expected that some day, “possibly even in the not very distant future,” visitors might see for themselves whether there is life on the moon, or even Mars.
But what was Winston Churchill doing penning a lengthy essay on the probability of alien life in the first place? After all, it was the eve of a war that would decide the fate of the free world, and Churchill was about to become Prime Minister of the United Kingdom.
Such an undertaking was actually quite typical for Churchill, notes Andrew Nahum, Keeper Emeritus at the Science Museum, London, because it reflects both his scientific curiosity and his recurring need to write for money. It was skill with the pen that often supported Churchill and his family's lavish lifestyle (recall that he won the 1953 Nobel Prize for Literature, with a monetary award of 175,293 Swedish Kroner worth about $275,000 today).
“One recent biography is entitled No More Champagne: Churchill And His Money,” Nahum says. “That was a phrase he put into a note to his wife about austerity measures. But he didn't know much about austerity. He liked luxury so he wrote like crazy, both books and articles that his agent circulated widely.”
That’s not to say that Churchill was simply slinging copy about aliens for a paycheck. “He was profoundly interested in the sciences and he read very widely,” notes Nahum, who curated the 2015 Science Museum exhibition “Churchill's Scientists.” Nahum relates the tale of how as Chancellor of the Exchequer, Churchill was once sent a book on quantum physics, and later admitted that it had occupied him for the better part of a day that should have been spent balancing the British budget.
He not only read scientific content voraciously, but wrote on the topic as well. In a 1924 issue of Nash's Pall Mall Magazine, Churchill anticipated the power of atomic weapons. “Might not a bomb no bigger than an orange be found to possess secret power to destroy a whole block of buildings nay, to blast a township at a stroke?” he warned. In 1932, he anticipated the rise of test-tube meat in the magazine Popular Mechanics: “Fifty years hence, we shall escape the absurdity of growing a whole chicken in order to eat the breast or the wing, by growing these parts separately in a suitable medium,” he wrote.
In 1939 he authored three essays, tackling not just extraterrestrial life but the evolution of life on Earth and the popular biology of the human body. Two were published during 1942 by the Sunday Dispatch, Nahum discovered when reading Churchill's papers at the University of Cambridge. It remains a mystery why his thoughts on alien life went unpublished.
In the rediscovered essay, Churchill admits that, because of the great distances between us and other planet-harboring stars, we may never know if his hunch that life is scattered among the vastness of the cosmos is correct. Yet even without proof, Churchill seems to have convinced himself that such a possibility was likely—perhaps by swapping his scientific mind for one more finely attuned to the human condition during the troubled 20th century.
“I, for one, am not so immensely impressed by the success we are making of our civilization here that I am prepared to think we are the only spot in this immense universe which contains living, thinking creatures,” he wrote, “or that we are the highest type of mental and physical development which has ever appeared in the vast compass of space and time.”
Seventy-five years after Churchill's bold speculations, there's still no proof that life exists on other worlds. But, as was often the case, his analysis of our own still seems prescient.
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About Brian Handwerk
If aliens ever sent us a message, scientists hope to pick it up in a remote part of northern California.
There, in a clearing nestled amid the volcanoes of the Cascade Range, 42 radio dishes point together at the sky. The dishes, each 20 feet across, form a single, giant scientific instrument called the Allen Telescope Array. Scientists built the array to receive radio signals — the sort of message that could answer a very important question: Are we the only intelligent life in this vast universe?
“It’s a question humans have been asking forever,” observes astronomer Jill Tarter. Until recently, she directed the SETI (Search for Extra-Terrestrial Intelligence) Institute in Mountain View, Calif. “We read these ancient texts, and the ancient Greeks, the Romans, the Chinese — they were all wondering how we humans fit into the universe.” The SETI Institute helped build the Allen Telescope Array in hopes of finding some answers.
While the question is ancient, our understanding of the universe has changed over the centuries. We now know that stars do not hang from the sky like fruit on a tree. We also know Earth orbits the Sun and not the other way around. But we still don’t know if life exists elsewhere. And if extraterrestrial life does exist, does it have the technology to communicate with us on Earth?
If so, the Allen Telescope Array is listening, day and night, for some signal. From time to time, the dishes pivot toward a new patch of the sky. The array has not yet picked up any alien calls. So far, intelligent life appears limited to Earth.
But that has hardly frustrated scientists. The search for life elsewhere in the universe continues to prove irresistible to experts in a wide variety of fields, from biology to astronomy, and from psychology to computer science. And they’re not just looking for aliens that can communicate: Many researchers suspect that simpler, microscopic alien life might be lurking on some distant planet.
Even if their quest has yet to turn up any aliens, it has led to some surprising discoveries — including some right here on Earth. If anything, the search for extraterrestrial life has become a lot more exciting. Perhaps it’s just a matter of time until we discover we’re not alone.
In 1960, astronomer Frank Drake (father of Science News writer Nadia Drake) was among the first to listen for extraterrestrial radio signals. That was decades before anyone knew whether any aliens out there even had a place to call home. We now know they might, thanks to discoveries since 1995 of planets outside our solar system.
To date, astronomers have found hundreds of these far-off worlds, called exoplanets. Some scientists predict hundreds of billions more exoplanets await discovery in our galaxy, the Milky Way. It’s easy to imagine there must be life on at least one of those planets. And if not there, perhaps life thrives on some moon orbiting one of those planets.
“Some may be at the right temperature where liquid water might exist. And that’s necessary for life as we know it,” says Tarter.
The discovery of so many new worlds, most of them found by the Kepler space telescope, has helped narrow the search for aliens. Tarter says the Allen Telescope Array now points at stars Kepler has flagged as having planets. Astronomers elsewhere in the United States and abroad have joined the hunt for life elsewhere in the universe.
Scientists searching for extraterrestrial life aren’t just looking up. Biologists, who study life in all of its forms, have joined the search too. They peer down into some of Earth’s most unfriendly places to find tiny but tough organisms called extremophiles (ex TREEM oh fylz). For more than 50 years, scientists have found extremophiles in places where life wasn’t thought to be possible.
Some of these microbes live in the acidic sulfur springs of Yellowstone National Park. Some thrive near cracks in the ocean floor — called hydrothermal vents — that spew scalding water. Others flourish in cracks in the ice in Antarctica, or deep underground in mines.
The discovery that life on Earth can survive under such harsh conditions has broadened the understanding scientists have of where they might find life off Earth.
“By learning more about the boundaries of life here on Earth, we can improve our definition of what life is and what it can tolerate,” says Jamie Foster. This biologist at the University of Florida studies extremophiles. “It’s really important to turn over every rock and look in every environment," says Foster. "The envelope of life keeps getting bigger and bigger with the discoveries of life in these extreme environments.”
Extremophiles on Earth suggest that scientists may not have to study some distant star to find evidence of extraterrestrial life. They may not be intelligent, but single-celled life-forms could be hiding relatively close by. Scientists point to one candidate site: Europa, a moon of Jupiter. It probably hides a vast, slushy ocean beneath its smooth, icy surface. Measurements also suggest it might host superhot hydrothermal vents — like those found on the floor of oceans on Earth.
“We know that life can exist here on Earth in that kind of environment, so it might be possible on Europa,” Foster says.
There is no immediate plan to send spacecraft off to find out. But later this summer, a NASA rover called Curiosity should arrive at Mars. It “will give us a really interesting clue as to whether Mars is potentially habitable now or possibly was in the past," says Foster. "Most people think that if life exists on Mars, it’s probably under the surface.”
It will take future missions to explore the depths of Mars and Europa for signs of life. Meanwhile, the search for life continues to engage scientists in a surprising variety of ways. While some remain busy with the hunt itself, others are already thinking way ahead to the day we might make contact.
Speaking in numbers
“If we get a message from another civilization, it’s not going to be in English or Chinese or Swahili,” says psychologist Douglas Vakoch. He is director of Interstellar Message Composition at the SETI Institute. “What language do we have in common? The usual starting place is math and science.”
Math is sometimes called the universal language. Though people may speak very different languages in different countries, math works the same everywhere. If you have two rocks and scoop up three more, you end up with five — regardless of where you live. We all share the same basic rules of addition, subtraction, multiplication and division. Researchers like Vakoch argue that if the language of math can be understood among nations, then why not among planets?
If an alien civilization can beam a message across space, then it must have first created some kind of transmitter, Vakoch observes. Building a transmitter — or any instrument that sends energy through space — requires a lot of knowledge about math. And if that alien math really is the same as human math, then it offers us a way to communicate. So it is easy to imagine that the first message from aliens may consist of radio pulses that follow a mathematical pattern. For example, we may receive pulses in multiples of two: first two, then four, followed by six, eight and so on.
Vakoch tries to predict what an incoming alien message might look like. He also works with other scientists to determine what kind of outgoing messages we should send back. It might be useful to send pictures of human beings to other civilizations, for example, or to include information about biology and life on Earth.
“We’re looking for ways to communicate something that can be described in scientific terms,” he says.
That is just what some scientists have already done. On November 16, 1974, researchers led by Frank Drake transmitted a message from the Arecibo Radio Telescope in Puerto Rico toward a distant grouping of stars. The radio pulses followed a numerical pattern, encoding a sort of “introduction to Earthlings” for aliens. The message contained information about human beings, our counting numbers, the radio telescope and the solar system.
“The message was repeated a couple of times,” Vakoch says. “That’s one way to make sure it remains intelligible even if there’s some error in transmission.”
So far, there’s been no answer. But nobody expected one yet — the message will take about 25,000 years to reach its destination.
If and when a message from an alien civilization does arrive, it may come as a series of super-short bursts of light or as a packet of radio waves. Whatever the message’s form, it likely will have traveled for thousands or even millions of years across space — even if all it offers us is a brief “hello” from a civilization just as unsure about the universe as we are.
That uncertainty helps make the search for extraterrestrial life so interesting, says Tarter, who has spent 20 years studying ways to listen for aliens. In May, she changed gears, going from searching for alien signals to raising money for the institute. Listening for aliens offers endless opportunities for anyone curious about our place in the universe, she says.
“There are a lot of things we don’t know, and you may have the opportunity to figure them out,” Tarter says. “Science is about constantly asking ‘why’ and figuring out the answers to questions that nobody else has answered.”
She notes that any message — even a simple “hi” — would have enormous implications for all humans. A message will have to travel thousands, if not millions, of years to get from planet to planet. By the time we receive a signal, the civilization that sent it might not even exist any more, which means we might not make new alien friends.
But if we receive a message, Tarter says, “then we’ll know that it’s possible to survive all the problems we have created for ourselves, and work our way out of them. I can’t imagine anything more profound than learning that it’s possible to grow old as a civilization.”
radio wave An electromagnetic wave used for long-distance communication. Radio waves are longer than the waves of visible light.
extraterrestrial Anything of or from regions beyond Earth.
extremophile A microorganism that lives in conditions of extreme temperature, acidity, alkalinity or chemical concentration.
astronomy The study of stars, space and the universe as a whole.
exoplanet A planet that orbits a star outside the solar system.
hydrothermal vent An opening in the sea floor out of which heated, mineral-rich water flows.
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