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Tagged with “astrobiology” (7)

  1. Carolyn Porco: Searching for Life in the Solar System - The Long Now

    Life nearby

    If we find, anywhere in the universe, one more instance of life besides what evolved on Earth, then we are bound to conclude that life is common throughout the vastness of this galaxy and the 200 billion other galaxies.

    The discovery would change how we think about everything.

    Most of the search for life beyond Earth, Porco explained, is the search for habitats.

    They don’t have to look comfy, since we know that our own extremophile organisms can survive temperatures up to 250°F, total desiccation, and fiercely high radiation, high pressure, high acidity, high alkalinity, and high salinity.

    In our own Solar System there are four promising candidate habitats—Mars, Europa (a moon of Jupiter), Titan (a moon of Saturn), and Enceladus (“en-SELL-ah-duss,” another moon of Saturn).

    They are the best nearby candidates because they have or have had liquids, they have bio-usable energy (solar or chemical), they have existed long enough to sustain evolution, and they are accessible for gathering samples.

    On Mars water once flowed copiously.

    It still makes frost and ice, but present conditions on Mars are so hostile to life that most of the search there now is focussed on finding signs of life far in the past.

    Europa, about the size of Earth’s Moon, has a salty ocean below an icy surface, but it is subject to intense radiation.

    Photos from the Hubble Space Telescope revealed that occasional plumes of material are ejected through Europa’s ice, so future missions to Jupiter will attempt to fly by and analyze them for possible chemical signatures of life.

    The two interesting moons of Saturn are Titan, somewhat larger and much denser than our Moon, and tiny Enceladus, one-seventh the diameter of our Moon.

    Both have been closely studied by the Cassini Mission since

    2004.

    Titan’s hazy atmosphere is full of organic methane, and its surface has features like dunes and liquid-methane lakes “that look like the coast of Maine.”

    But it is so cold, at 300°F below zero, that the chemical reactions needed for life may be too difficult.

    Enceladus looks the most promising.

    Cassini has sampled the plumes of material that keep geysering out of the south pole.

    The material apparently comes from an interior water ocean about as salty as our ocean, and silica particles may indicate hydrothermal vents like ours.

    “I hope you’re gettin excited now,” Porco told the audience, “because we were.”

    The hydrothermal vents in Earth’s oceans are rich with life.

    Enceladus has all the ingredients of a habitat for life—liquid water, organics, chemical energy, salts, and nitrogen-bearing compounds.

    We need to look closer.

    A future mission (arriving perhaps by the 2030’s) could orbit Enceladus and continually sample the plumes with instruments designed to detect signs of life such as complexity in the molecules and abundance patterns of carbon in amino acids that could indicate no biology, or Earth-like biology, or quite different biology.

    You could even look for intact organisms.

    Nearly all of the material in the plumes falls back to the surface.

    Suppose you had a lander there.

    “It’s always snowing at the south pole of Enceladus,” Porco said.

    “Could it be snowing microbes?”

    (A by-the-way from the Q&A:

    Voyager, which was launched 40 years ago in 1977, led the way to the outer planets and moons of our Solar System, and five years ago, Porco pointed out, “It went beyond the magnetic bubble of the Sun and redefined us as an interstellar species.”)

    —Stewart Brand

    http://longnow.org/seminars/02017/jul/24/searching-life-solar-system/

    —Huffduffed by adactio

  2. Sara Seager: Other Earths. Other Life. - The Long Now

    We are one tool away from learning which distant planets already have life on them and which might be welcoming to life.

    MIT Planetary Scientist Sara Seager is working on the tool. She is chair of the NASA team developing a “Starshade” that would allow a relatively rudimentary space telescope to observe Earth-size planets directly, which would yield atmospheric analysis, which would determine a planet’s life-worthiness.

    Despite 1,000-plus exoplanet discoveries by the Kepler spacecraft and the hundreds more expected from the Transiting Exoplanet Survey Satellite after 2017, neither instrument can make detailed observation of the atmosphere of small rocky planets, because each star’s brilliance overwhelms direct study of the rocky motes that might harbor life. A Starshade cures that.

    A former MacArthur Fellow, Seager is author of Exoplanet Atmospheres (02010) and an astrophysics professor at MIT. Her maxim: “For exoplanets, anything is possible under the laws of physics and chemistry.”

    http://longnow.org/seminars/02015/aug/10/other-earths-other-life/

    —Huffduffed by adactio

  3. Space talk: Ann Leckie and Caleb Scharf

    This week we’re leaving planet Earth behind, with the astrobiologist Caleb Scharf and the science-fiction phenomenon Ann Leckie.

    Recent advances in astrophysics have allowed scientists to find planets orbiting around remote stars, with more than a thousand distant exoplanets identified in the last 20 years. Scharf explores the competing pulls of two principles which have guided modern astronomers, and outlines his proposal for a middle way where human life is "special but not significant, unique but not exceptional".

    The novelist Ann Leckie is both significant and exceptional, carrying off an unprecedented sweep of science fiction’s most prestigious awards with her debut novel, Ancillary Justice. She talks about how she got into the head of a vast, distributed intelligence, why gender politics made their way into her novels and the different ways in which scientific discoveries fire the SF imagination.

    http://www.theguardian.com/books/audio/2014/oct/17/ann-leckie-caleb-scharf-science-fiction-astrobiology-podcast

    —Huffduffed by adactio

  4. Big Picture Science: Long Live Longevity

    Here’s to a long life – which, on average, is longer today than it was a century ago. How much farther can we extend that ultimate finish line? Scientists are in hot pursuit of the secret to longer life.

    The latest in aging studies and why there’s a silver lining for the silver-haired set: older people are happier. Also, what longevity means if you’re a tree. Plus, why civilizations need to stick around if we’re to make contact with E.T.

    And, how our perception of time shifts as we age, and other tricks that clocks play on the mind.

    http://radio.seti.org/episodes/Long_Live_Longevity

    —Huffduffed by adactio

  5. Paul Davies: Are we alone in the universe?

    Is intelligent life trying to communicate with us from space? Professor Paul Davies explores the potential and limits of research into the origin and evolution of life, and the search for life beyond Earth. Has ET maybe visited our planet ages ago and left us a message? At the Australian National University, Paul Davies discussed his latest book The Eerie Silence: Are We Alone in the Universe?

    —Huffduffed by adactio

  6. Finding intelligent life with telescopes and computers

    Are human beings the only example of intelligent life in the universe?

    Dr. Jill Tarter, director for the Center for SETI Research, says it’s scientifically valid to ask if the same processes of physics and chemistry that resulted in human life and civilization might have occurred elsewhere in the universe.

    In this short podcast presentation, Dr. Tarter talks about the role that the Allen Telescope Array is playing in the effort to identify signals engineered by non-human life if it exists somewhere in the cosmos.

    "Life on earth is made out of stardust. Life somewhere else is going to probably be made out of stardust too."

    http://domino.research.ibm.com/comm/research.nsf/pages/d.compsci.seti.html

    —Huffduffed by adactio