SETI bioastro: Is It Time to Scrap SETI?

From: LARRY KLAES (ljk4_at_msn.com)
Date: Thu Dec 16 2004 - 08:26:32 PST

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    http://abcnews.go.com/Technology/DyeHard/story?id=311101&page=1>

    Is It Time to Scrap SETI?

    Researchers Claim Listening For Signals From ET Is Futile

    Dec. 9, 2004 - For all those folks out there who are counting the days
    until we hear from some intelligent creature on another planet,
    researchers now say we're not going to be able to eavesdrop on the space
    alien equivalent of the "I Love Lucy" show.

    During the few decades that scientists have searched systematically for
    life elsewhere in the universe there has been some hope that
    electromagnetic "leakage" from communications systems on other planets --
    such as television broadcasts -- might be detectable from Earth. If that's
    the case, then radio telescopes sweeping the sky might pick up those
    signals, giving us a window onto other worlds, and finally answering that
    increasingly overworked question, "Are we alone?"

    Don't count on it, say researchers from three institutions. Any advanced
    civilization would likely encode and compress their communications to make
    their systems more efficient, just as your computer compresses files that
    you send over the Internet, the researchers argue in a report in a recent
    issue of the "American Journal of Physics."

    And that, they say, would make those signals indistinguishable from the
    thermal radiation of stars, and thus impossible to detect because it would
    seem like part of the universe's background noise.

    Even if we did somehow capture such a signal, we wouldn't know it, says
    physicist Mark Newman of the University of Michigan in Ann Arbor.

    "If you don't know how to decode it, then you can't make out what's going
    on," Newman says.

    The Decompression Issue

    A computer can't show a picture that has been compressed by another
    computer unless it knows how to decompress it, and likewise we couldn't
    decode a television signal that had been compressed unless we already knew
    the code. And, Newman and his colleagues argue, any advanced civilization
    which has used wireless communications for even a few decades would surely
    have figured out that it makes sense to encode.

    We're already doing it, and we're just barely in the communications age.

    "This is something we already do in many of our transmissions," Newman
    says. "We encode (compress) them so they take up less space and we can
    send them faster and send more messages."

    To be fair, the Search for Extraterrestrial Intelligence, or SETI as it
    has come to be known, has never been wedded to the idea that we could
    somehow tune in to alien television broadcasts. Astronomer Frank Drake,
    who many consider the father of the current effort, told me years ago that
    any such signal would probably be far too weak to detect on Earth.

    Thus the primary aim is to find signals that are intentionally sent in our
    direction by another life form, and thus designed to be easily detected by
    us. Newman has been informed of that by many irate readers of his report
    who maintain that the search is viable because no one is really listening
    for Lucy.

    Yet much of the SETI literature does suggest that ordinary communications
    signals might be detectable.

    And that's what compelled Newman and biologist Michael Lachmann of the Max
    Planck Institute in Leipzig, Germany, and computer scientist Christopher
    Moore of the University of New Mexico in Albuquerque to take a closer
    look.

    The three built on the pioneering research of Claude Shannon, an
    electrical engineer with Bell Labs who published two seminal papers in the
    1940s on information theory. Shannon demonstrated that it is possible to
    compress data and thus distribute far more information than would
    otherwise be possible. That work is the foundation for much of today's
    communication technology.

    Compressed data, however, looks like just a jumble of junk unless it is
    decoded, and the researchers wondered if that would apply to radio signals
    as well.

    "In our paper we proved that there's an equivalent result for radio
    messages," Newman says. "The most information-rich radio message looks
    like thermal radiation, which is the standard kind of radiation that we
    see in the sky. So that would make it difficult to tell the difference
    between an intentional transmission that was very efficient and just
    natural phenomena."

    Not a Peep in 10 Years

    But what if someone out there really is trying to contact us? That message
    would not likely be encoded because they -- whoever "they" might be --
    would want us to understand it.

    "Then, of course, you could easily see it," Newman admits.

    Which takes me back about a dozen years to a time when I sat on the porch
    of Frank Drake's California home and listened to this eloquent scientist
    talk about the passion in his life, somehow finding ET.

    He said all those years ago that routine signals from another planet would
    spread out as they passed through space, weakening as their footprint grew
    ever larger. And just as a flashlight grows dimmer with distance, they
    would probably be far too weak to detect by the time they reached Earth.

    But what if someone is beaming a very tightly focused, high-powered
    transmission directly at us? Surely we could find that pretty easily.

    Drake's enthusiasm has always been infectious, but I wondered out loud how
    long that enthusiasm would last. With trillions of stars out there, how
    long would he be willing to search? When might he decide that perhaps he
    was on the wrong track, that perhaps ET is illusive, or isn't interested
    in our primitive society?

    I don't have the notes from that meeting, and couldn't reach Drake for
    this column, but I remember what he said. Picking a number out of the air,
    he said if scientists hadn't found anything in about 10 years, perhaps
    they would have to rethink their program.

    The SETI Institute in Mountain View, Calif., which Drake helped found, has
    now grown into a large organization of more than 100 scientists and
    staffers, due largely to the largess of a number of folks with very deep
    pockets.

    It is more than 20 years old now.

    And in all those years of searching, not a single signal has turned out to
    mean anything at all. If ET is trying to reach us, she must not be trying
    very hard.

    Lee Dye's column appears weekly on ABCNEWS.com. A former science writer
    for the Los Angeles Times, he now lives in Juneau, Alaska.

     


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