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  • richardmitnick 2:57 pm on August 19, 2014 Permalink | Reply
    Tags: , SETI,   

    From The New York Times: “The Intelligent-Life Lottery” 

    New York Times

    The New York Times

    AUG. 18, 2014
    George Johnson

    Almost 20 years ago, in the pages of an obscure publication called Bioastronomy News, two giants in the world of science argued over whether SETI — the Search for Extraterrestrial Intelligence — had a chance of succeeding. Carl Sagan, as eloquent as ever, gave his standard answer. With billions of stars in our galaxy, there must be other civilizations capable of transmitting electromagnetic waves. By scouring the sky with radio telescopes, we just might intercept a signal.

    But Sagan’s opponent, the great evolutionary biologist Ernst Mayr, thought the chances were close to zero. Against Sagan’s stellar billions, he posed his own astronomical numbers: Of the billions of species that have lived and died since life began, only one — Homo sapiens — had developed a science, a technology, and the curiosity to explore the stars. And that took about 3.5 billion years of evolution. High intelligence, Mayr concluded, must be extremely rare, here or anywhere. Earth’s most abundant life form is unicellular slime.

    Since the debate with Sagan, more than 1,700 planets have been discovered beyond the solar system — 700 just this year. Astronomers recently estimated that one of every five sunlike stars in the Milky Way might be orbited by a world capable of supporting some kind of life.

    That is about 40 billion potential habitats. But Mayr, who died in 2005 at the age of 100, probably wouldn’t have been impressed. By his reckoning, the odds would still be very low for anything much beyond slime worlds. No evidence has yet emerged to prove him wrong.

    Maybe we’re just not looking hard enough. Since SETI began in the early 1960s, it has struggled for the money it takes to monitor even a fraction of the sky. In an online essay for The Conversation last week, Seth Shostak, the senior astronomer at the SETI Institute, lamented how little has been allocated for the quest — just a fraction of NASA’s budget.

    “If you don’t ante up,” he wrote, “you will never win the jackpot. And that is a question of will.”

    Three years ago, SETI’s Allen Telescope Array in Northern California ran out of money and was closed for a while. Earlier this month, it was threatened by wildfire — another reminder of the precariousness of the search.

    Allen Telescope Array
    Allen Telescope Array

    It has been more than 3.5 billion years since the first simple cells arose, and it took another billion years or so for some of them to evolve and join symbiotically into primitive multicellular organisms. These biochemical hives, through random mutations and the blind explorations of evolution, eventually led to creatures with the ability to remember, to anticipate and — at least in the case of humans — to wonder what it is all about.

    Every step was a matter of happenstance, like the arbitrary combination of numbers — 3, 12, 31, 34, 51 and 24 — that qualified a Powerball winner for a $90 million prize this month. Some unknowing soul happened to enter a convenience store in Rifle, Colo., and — maybe with change from buying gasoline or a microwaved burrito — purchase a ticket just as the machine was about to spit out those particular numbers.

    According to the Powerball website, the chance of winning the grand prize is about one in 175 million. The emergence of humanlike intelligence, as Mayr saw it, was about as likely as if a Powerball winner kept buying tickets and — round after round — hit a bigger jackpot each time. One unlikelihood is piled on another, yielding a vanishingly rare event.

    In one of my favorite books, “Wonderful Life,” Stephen Jay Gould celebrated what he saw as the unlikelihood of our existence. Going further than Mayr, he ventured that if a slithering creature called Pikaia gracilens had not survived the Cambrian extinction, about half a billion years ago, the entire phylum called Chordata, which includes us vertebrates, might never have existed.

    Gould took his title from the Frank Capra movie in which George Bailey gets to see what the world might have been like without him — idyllic Bedford Falls is replaced by a bleak, Dickensian Pottersville.

    For Gould, the fact that any of our ancestral species might easily have been nipped in the bud should fill us “with a new kind of amazement” and “a frisson for the improbability of the event” — a fellow agnostic’s version of an epiphany.

    “We came this close (put your thumb about a millimeter away from your index finger), thousands and thousands of times, to erasure by the veering of history down another sensible channel,” he wrote. “Replay the tape a million times,” he proposed, “and I doubt that anything like Homo sapiens would ever evolve again. It is, indeed, a wonderful life.”

    Other biologists have disputed Gould’s conclusion. In the course of evolution, eyes and multicellularity arose independently a number of times. So why not vertebrae, spinal cords and brains? The more bags of tricks an organism has at its disposal, the greater its survival power may be. A biological arms race ensues, with complexity ratcheted ever higher.

    But those occasions are rare. Most organisms, as Daniel Dennett put it in “Darwin’s Dangerous Idea,” seem to have “hit upon a relatively simple solution to life’s problems at the outset and, having nailed it a billion years ago, have had nothing much to do in the way of design work ever since.” Our appreciation of complexity, he wrote, “may well be just an aesthetic preference.”

    In Five Billion Years of Solitude, by Lee Billings, published last year, the author visited Frank Drake, one of the SETI pioneers.

    “Right now, there could well be messages from the stars flying right through this room,” Dr. Drake told him. “Through you and me. And if we had the right receiver set up properly, we could detect them. I still get chills thinking about it.”

    He knew the odds of tuning in — at just the right frequency at the right place and time — were slim. But that just meant we needed to expand the search.

    “We’ve been playing the lottery only using a few tickets,” he said.

    See the full article here.

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  • richardmitnick 2:49 pm on August 13, 2014 Permalink | Reply
    Tags: , , , , SETI, , ,   

    From SPACE.com: “Hairspray Chemical Could Aid Search for Alien Life” 

    space-dot-com logo

    SPACE.com

    August 13, 2014
    Charles Q. Choi

    Chemicals once found in hairspray may serve as signs of alien life on faraway worlds, researchers say.

    These compounds may reveal that extraterrestrials have disastrously altered their planets, scientists added.

    To detect biomarkers, or signs of life, on distant worlds, scientists have often focused on molecules such as oxygen, which theoretically disappears quickly from atmospheres unless life is present to provide a constant supply of the gas. By looking at light passing through atmospheres of alien worlds, past studies have suggested future instruments such as NASA’s James Webb Space Telescope could detect telltale traces of oxygen.

    But the search for extraterrestrial intelligence (SETI) has mostly concentrated on “technosignatures,” such as radio and other electromagnetic signals that alien civilizations might give off. Now researchers suggest that searches for atmospheric biomarkers could also look for industrial pollutants as potential signs of intelligent aliens.

    SETI ATA
    SETI Institute’s Allen Telescope Array

    SETI@home screensaver
    SETI@home, citizen science, Public Distributed Computing running on BOINC software

    Astronomers at Harvard University focused on tiny, superdense stars known as white dwarfs. More than 90 percent of all stars in the Milky Way, including our own sun, will one day end up as white dwarfs, which are made up of the dim, fading cores of stars.

    sirius
    Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint pinprick of light to the lower left of the much brighter Sirius A.

    Though white dwarfs are quite cold for stars, they would still be warm enough to possess so-called habitable zones — orbits where liquid water can exist on the surfaces of circling planets. These zones are considered potential habitats for life, as there is life virtually everywhere there is liquid water on Earth.

    The scientists examined how Earth-size planets in the habitable zones of white dwarfs might look if they possessed industrial pollutants in their atmosphere. They focused on chlorofluorocarbons (CFCs), which are entirely artificial compounds, with no known natural process capable of creating them in atmospheres.

    CFCs are nontoxic chemicals that were once used in hairspray and air conditioners, among many other products, before researchers discovered they were causing a hole in Earth’s ozone layer, which protects the planet from dangerous ultraviolet radiation.

    “Very hairy extraterrestrials may be a little easier to detect,” joked lead study author Henry Lin, a physicist at Harvard.

    CFCs are strong greenhouse gases, meaning they are very effective at absorbing heat. This means that if CFCs are in the atmosphere of a distant Earth-size planet, they could alter a white dwarf’s light when that world passes in front of that star — enough for the $8.8 billion James Webb Space Telescope (JWST), which is due to launch in 2018, to detect them.

    In addition, the researchers noted that CFCs are long-lived molecules, capable of lasting up to about 100,000 years in atmospheres. This means they could even serve as markers of long-dead alien civilizations. [10 Alien Encounters Debunked]

    The investigators simulated the amount of time it would take JWST to detect the fluorocarbon CF4 and the chlorofluorocarbon CCl3F in the atmosphere of an Earth-size planet in the habitable zone of a white dwarf. They modeled concentrations of these gases 100 times greater than the highs currently seen on Earth.

    The scientists found it would take JWST three days of looking at such a white dwarf to detect signs of CF4, and only a day and a half for CCl3F.

    NASA Webb Telescope
    NASA/Webb

    “The most exciting aspect of the results is that within the next decade we might be able to search for excessive industrial pollution in the atmospheres of Earth-like planets,” study co-author Abraham Loeb, a theoretical astrophysicist and chair of Harvard’s astronomy department, told Space.com.

    Ironically, “aliens are often referred to as green little creatures, but ‘green’ also means ‘environmentally friendly,'” Loeb said. “Detectable CFC-rich civilizations would not be ‘green.'”

    The scientists did caution that it would take much longer to detect these industrial pollutants than it would biomarkers such as oxygen, which JWST could find after about three hours of looking at such a planet. Astronomers should only attempt to discover technosignatures such as CFCs if initial searches for fundamental biomarkers like oxygen were successful, the research team suggested.

    The astronomers cautioned it would be 100 times more difficult to detect industrial pollutants on planets orbiting yellow dwarf stars like the sun, making such searches beyond the capabilities of JWST. It would also take an unrealistically long time to detect CFC levels on alien planets that match those currently found on Earth, Loeb said.

    One potentially sobering future discovery might be of alien worlds that possess long-lived industrial pollutants such as CFCs but no longer have any short-lived biomarkers such as oxygen.

    “If we find graveyards of other civilizations, most rational people would likely get engaged in protecting the Earth from a similar catastrophe,” Loeb said.

    “We call industrial pollution a biomarker for intelligent life, but perhaps a civilization much more advanced than us with their own exoplanet program will classify industrial pollution as a biomarker for unintelligent life,” Lin said

    However, if astronomers discover a world heavy with CFCs that exists outside the habitable zone of its star, that could mean an extraterrestrial civilization may have intentionally “terraformed” that planet, making it livably warmer “by polluting it with greenhouse gases,” Loeb said. Scientists have previously suggested terraforming Mars by warming and thickening the Red Planet’s atmosphere so that humans can roam its surface without having to wear spacesuits.

    The scientists detailed their findings in a paper submitted to the Astrophysical Journal.

    See the full article here.

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