This is Yves. I was a very active science fiction reader throughout my adolescence and much of my adulthood. But I’m not at all optimistic that humans will find forms of life, as we choose to define it, outside of our solar system, given the enormous distances from our very short lifespan. . On the other hand, however, most commentators have a narrow-minded view of what life is, to the extent that it is presumed to be biological. Why aren’t stars on the list? Couldn’t this be life operating on a very different time scale than ours?
By Sarah Scoles, Colorado-based science journalist and senior contributor to Undark. She is the author of “Contact,” “They are already there” And “Countdown: The Blinding Future of 21st Century Nuclear Weapons.” » Originally published on In darkness
Lisa Kaltenegger’s lab has a bit more color than a typical research facility, filled with a plethora of luminous glassware. It’s the kind of rainbow network you might expect to see in a life scientist’s lab. But Kaltenegger is not an expert on life, nor does she grow colorful organisms in these little transparent houses for biological study. She is an astronomer and wants to know how masses of microbes located on distant planets could appear through a telescope.
Kaltenegger populated petri dishes and other containers with organisms like algae, samples of which she coaxed from her life sciences colleagues at Cornell University. Each species changes the hue of its environment in a particular way, transforming the deserts, ice or hot springs from which it came – or, in this case, the color palette of Kaltenegger’s laboratory. Ocean algae, for example, can create a crimson bloom, while some inhabitants of sulfur hot springs produce a mustard hue.
Kaltenegger’s lab is part of the Interdisciplinary Carl Sagan Institute, which she founded with the goal of discovering life in the universe. His new book “Extraterrestrial Earths: The New Science of Planet Hunting in the Cosmos” details the research that aims to find such life forms and understand the planets they may inhabit – a quest that, for her, sometimes begins with these colorful organisms.
Once a given group of organisms has grown sufficiently, Kaltenegger and his colleagues load it into a backpack and bring it to Cornell’s civil engineering department. There, scientists can use remote sensing equipment to view the samples as a telescope would, measuring the different color patterns of light that result. This way, the idea goes, scientists can recognize potential extraterrestrial organisms – which could, hypothetically, resemble algae and algae-altering Earth alterations – from a distance, based on their color fingerprints.
Information about their color is then fed into computer models created by Kaltenegger of planets, both real and hypothetical. “A few touches allow me to move the planet closer to the star, manipulate the color of its sun, increase its gravity, create sand dunes, oceans or jungles across the world, and add or to eliminate life forms,” writes Kaltenegger. “I create worlds that could exist and light imprints to search for with our telescopes.”
In “Alien Earths”, Kaltenegger outlines the state and challenges of this research, while exploring the range of planets found there. this solar system and beyond, all with the aim of answering this ultimate question: Are we alone? “The question must have an obvious answer: yes or no,” she writes. “But once you try to find life elsewhere, you realize it’s not that simple. Welcome to the world of science.
Kaltenegger launches “Alien Earths” by creating the different ways that people have been thinking about life in the universe – or rather the lack of evidence so far. But the bulk of the book is about investigating how and where life might arise in the universe, and how humans might recognize it. In this quest, she bounces from planetary evolution to exoplanet studies, from biological evolution to telescope technology, the text being as interdisciplinary as her institute.
There is a lot of ground to cover, and the flow of the book is not always tightly organized thematically. But what the book perhaps lacks in structural coherence, it makes up for in gripping detail that takes readers into the titular worlds – and may lead them to observe their own planet from afar, as an alien would through his own telescope.
Take the imaginary planet that begins the book: one where an entire hemisphere is always dark, the other always light: “You wait for the sunset and the darkness of night, but they never come,” writes -She. “To experience nightfall, one must travel for days to the other end of this distant planet, the place of eternal twilight. »
The text shines most when Kaltenegger talks about his own research, fascinating in its inventiveness. In the digital planets she creates, informed by her experiences, she acts as a kind of god, manipulating them at will and out of curiosity. “I can cover the oceans with green algae blooms or dot the continents with yellow microbial mats,” she says. “Without leaving my office, I can create new worlds. »
Kaltenegger explains this complex science in a simple, sometimes lyrical and often humorous way. For example, when discussing whether and how humans might communicate with extraterrestrial life, she writes that “the experience might end up being like a human trying to talk to a jellyfish.” I tried this; the results were far from promising.
The book also presents the kind of big-picture cosmic facts that blow away every new generation of pop science readers, like when she explains how the speed of light affects our perception of stars: “Because light needs time to to travel. through the cosmos you can find a connection to your own past in the sky,” she writes. “There is a star in the night sky whose light emitted when you were born and which has only just arrived now.”
Sometimes humor and jaw-dropping come in one package, as in Kaltenegger’s description of the solar system revolving around the center of the galaxy. “If you ever feel stuck,” she writes, “remember: cosmologically speaking, you are not. You rush through the cosmos. And you are part of it.
In this cosmos, scientists have discovered more than 5,000 distant planets over the past 30 years, a wave of discoveries that Kaltenegger traces, with descriptions as rich as his imagined creations. For example, the planet CoRoT-7 b, discovered in 2009, is so hot that it melts its own rocks. These liquefied rocks evaporate, then fall back to the cursed ground in the form of lava rain.
Kaltenegger experimented with a similar lava planet in his lab, to understand again how a telescope could see such a place: his team selected 20 different varieties of rocks that could be found on the planets, then mixed them together in powder form to get the compositions for the type of planet they wanted to create. When placed on a heated metal strip, they become small-scale lava – a sort of linear lava planet. “The worlds we create are so small that they can easily fit in the palm of my hand,” Kaltenegger writes. She and her colleagues then try to understand what this lava would look like on a large scale to a telescope, so they can compare that signature to the sites they actually see.
Readers may be surprised, however, to find that much of “Alien Earths” focuses on This Earth and its close neighbors in the solar system. “When we search the cosmos for life, Earth is our only key to unlocking the secrets of what it needs to get started,” says Kaltenegger. Exoplanet scientists therefore spend much of their time studying their environment more closely: life flourishing in their own petri dishes, the evolution of familiar continents, records of meteorite impacts or the way the atmosphere has changed over time.
Conversely, studying other planets could reveal more about Earth and how it managed to support life. Other planets could also serve as warnings: “Exploring space allows us to gain the knowledge needed to save us from asteroids, pollution and the depletion of Earth’s limited resources,” writes Kaltenegger.
But according to her, the best way for humans to save themselves in the long term is not necessarily to ward off planetary unrest. It’s to get out of here. All planets – foreign or not, polluted or not – will one day become uninhabitable: the stars on which they orbit will go out “in a burning blaze of glory”, causing life to boil away, or they will slowly become darker and their worlds will disappear. will cool slowly. . Although it won’t happen on Earth for billions of years, Kaltenegger has a suggestion: “Let’s become wanderers of this amazing universe,” she writes. “It doesn’t have to end in fire or ice.”
