Signs of Life

“If alien astronomers are out there searching for signs of life on Earth, they might just find it in the telltale pattern of light reflected by our plants, from redwood forests to desert cacti to grass-covered plains. That reflected fingerprint has been visible since vegetation first began carpeting our rocky terrestrial landscape about half a billion years ago. And as Earth aged and evolution marched onward, the reflected signal strengthened.

“Now, two astronomers are suggesting that plants could leave similar fingerprint-like patterns on distant exoplanets, and perhaps the first signs of life beyond our solar system could come from light reflected by forests covering an alien moon like Endor or cacti living in Tatooine’s deserts.

 
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“We’re trying to figure out—with all the planets we’re finding—what are the signatures that could indicate habitability?” says Cornell University’s Lisa Kaltenegger, who recently described Earth’s leafy signature in a study published in the journal Astrobiology.

“We really want to identify the handful, or two or three, that give us the best chance to pick up signs of life.”

“While this isn’t the first time scientists have suggested looking for life in a far-off planet’s light, Kaltenegger’s team adds a twist: Such reflections can also offer a good estimate for an alien planet’s evolutionary advancement, based on our knowledge of how things work on Earth.

“This idea that you could find vegetation on another planet has been around. But nobody ever used Earth’s own geological history as an archive,” Kaltenegger says. “We don’t have a second planet with habitability, but we do have our Earth through time, and it would be really smart to study it.”

“Several decades ago, the Galileo spacecraft, which was headed for Jupiter, swiveled to stare at Earth’s reflected light. It spied the signs of biology at work in the presence of atmospheric gases such as ozone and methane. More recently, astronomers have teased apart Earthshine, or the bit of Earth-light that sometimes dimly illuminates the darker part of a crescent moon’s face. They found life’s fingerprints there, too.

“Now, scientists searching for life beyond Earth are debating how biology might leave molecular marks in alien atmospheres, either by producing particular compounds or by shifting the mix of gases swaddling a planet.”

Text: “Want to Find Alien Life? Look at Older, Hotter Earths”, National Geographic.
Image: L’occhio di Shui (The Eye of Shui) by Shui Mao.

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“The alien, the industrial & the natural…”

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“In Dan Holdsworth’s latest series Transmission: New Remote Earth Views, he appropriates topographical data to document the ideologically and politically loaded spaces of the American West in an entirely new way. In his images of the Grand Canyon, Yosemite, Mount Shasta, Mount St. Helens, Salt Lake City and Park City, we see stark, uninterrupted terrains where meaning is made through what it is absent, as much as what is seen. What at first appears to be a pure white snow-capped mountain is in fact a digitally rendered laser scan of the earth appropriated from United States Geological Survey data, a ‘terrain model’ used to measure climate and land change – to measure man’s effect on the earth. Belying his empirical methodology is the fact that each of these terrains has a rich and conflicting cultural legacy. Beginning with the idealised aesthetic of the Romantic sublime via the deadpan industrial frames of the New Topographics photographers a century later, each has been subject to the gaze of artistic, political, and sociological categories claiming this territory as their own. Extending ideas of the frontier and seeing anew, Transmission captures the world as if from space, functioning not only as a map of the land but as a mapping of the discourses that these lands have come to represent. Working outside of the wilderness myths that render the images from the photographic avant-garde the ‘after’ to nineteenth-century visions of Carlton Watkins’ ‘before’, Holdsworth opens up a working territory that is open to the ambiguous and ethereal, oscillating between realms of art and science, the familiar and the alien, the industrial and the natural…”

Text & Pic: Dan Holdsworth, Transmission: New Remote Earths, 2012.