“We are now on our way on the most remarkable journey humanity ever undertook, searching for our origins and for a cosmic echo that will finally tell us one day that we are not alone,” writes eminent astrobiologist Nathalie A. Cabrol in her enthralling forthcoming book, The Secret Life of the Universe: An Astrobiologist’s Search for the Origins and Frontiers of Life. It is a dizzying odyssey which explores the biological prospects of life elsewhere in our solar system and beyond.
Born in France where her book is already a bestseller, Cabrol is a formidably impressive scientist who has conducted research into life’s adaptation to extreme environments for NASA, and who also holds the women’s world record for freediving at altitude (that is, at 300 metres or more above sea level). We speak via video call, Cabrol—from her base in the San Francisco Bay area of California where she is Director of the Carl Sagan Centre at SETI (Search for Extra-Terrestrial Intelligence). But more about Carl Sagan in a moment.
“I cannot say exactly when it started,” says Cabrol when I ask when her fascination with the universe began. “My mum would tell me that I was always pointing at the sky and that it was the first thing I talked about.”
She was five years old when Neil Armstrong stepped onto the moon. Watching the Apollo 11 moon landing on television was a defining moment: “It was the middle of the night but my mum kept me up and the two of us were on the couch, watching. I still have those images in my head.”
Cabrol embarked on her career as an astrobiologist around the time of “Cosmos”, Carl Sagan’s astounding and hugely successful TV series about the mysteries of space. The companion book, published in 1980 and also called Cosmos is still one of the bestselling books ever with around 40 million copies sold worldwide. Cabrol tells me a wonderful story about meeting Sagan in the mid-1990s, after emailing him to ask for advice on her next career steps after completing her Master’s degree in planetary science. Cabrol was the first woman in France to be working in that field: “It had been a very difficult journey for me to get to that point. But I was finally feeling that I was home.” Cabrol had little hope of a reply. “It was a bottle in the ocean but two hours later I had a response.” Sagan suggested they meet during a conference he was attending in Paris, and the two talked for more than an hour. “He was so patient, and never did he make me feel I was wasting his time. He felt very strongly about the next generation of scientists.”
Our exploration of the possibilities for life elsewhere in the universe teach us lessons that we need to integrate now… Otherwise we will disappear
Sagan was also renowned for his gift in science communication and, as well as his huge influence on Cabrol as a scientist, he has also inspired her—40 years on—to take up the baton of writing about her own work for a general audience. Following on from Sagan’s famous quote from Cosmos (“We have lingered long enough on the shores of the cosmic ocean. We are ready at last to set sail for the stars.”), she says: “There has been so much progress since Carl first talked about those shores and we are now well on the way in our voyage into the cosmic ocean. It was time to write about that.”
And indeed The Secret Life of the Universe—written first in French and then translated into English by its author—is revelatory about the progress we have made in understanding both the origins of life on earth and also how and where we might encounter it elsewhere in the universe. For in this golden age of astrobiology, not only have we discovered environments in our own solar system that “push back our conceptions of the last frontiers of habitability and where life could be waiting to be found” (on Mars, for example, but also on Titan, Saturn’s largest moon, and on dwarf planet Ceres), but also millions of exoplanets within our own galaxy alone that are capable of supporting life. If life on earth is an accident, writes Cabrol, “then the universe has to be the mother of all pile-ups”.
Space geeks will obviously love this book. But The Secret Life of the Universe contains plenty for all of us, including those who feel space exploration is an expensive folly given the problems we face on earth. Astrobiology, Cabrol argues, provides us with a “profound mirror reflecting our own existence”. As spacecraft voyage further and further from our cosmic shore, we also gain a much-needed bigger picture as we look back at the “Pale Blue Dot”—as Carl Sagan called it—where we live. This so-called Overview Effect (see extract) highlights our planet’s insignificance. Its marvels. Its fragility. “Our planet is not even a pixel when seen from Voyager. So when you think we are fighting so hard for a fraction of that dot, it doesn’t make any sense,” says Cabrol.
“What does it mean for a planet to be habitable? Astrobiology shows us how fragile habitability is. It isn’t something that is given forever, even if you don’t do anything to it. So there is no need for us add more instability.And yet we are overheating our atmosphere. This is Venus. We are losing our water. This is Mars. Our exploration of the possibilities for life elsewhere in the universe teach us lessons that we need to integrate now as a civilisation. Otherwise we will disappear. And nobody will care.”
Insignificant though we may be, we are also mighty, Cabrol argues: “We have the ability to explore, and to ask questions about ourselves. Isn’t that amazing?” She hopes that The Secret Life of the Universe will help us to make ours the age when humans rise to the challenge of becoming planetary citizens. Now is the time, she says, to “look in the mirror and ask ourselves—who do we want to become?”
