SETI bioastro: In hunt for E.T., a giant leap

From: LARRY KLAES (ljk4_at_msn.com)
Date: Thu Jul 08 2004 - 05:54:48 PDT

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    Headline: In hunt for E.T., a giant leap
    Byline: Peter N. Spotts Staff writer of The Christian Science Monitor
    Date: 07/08/2004

    For years, scientists have been listening for faint whispers of E.T.
    phoning anyone in electronic earshot. Now, some researchers are hearing
    sounds almost as exciting - the staccato of hammers, the crackle of arc
    welders, and the rumble of construction equipment - that signal the
    building of huge new telescopes to help answer an old question: Are we
    alone in the galaxy?

    The answer to that question looms closer, thanks to boosts in funding,
    facilities, astronomical discoveries, and advances in technology.
    Researchers say within a few years they'll be able to conduct far more
    exhaustive searches for civilizations beyond our solar system.

    The field "is in a stage of explosive growth," says Kent Cullers,
    director of research and development at the SETI Institute in Mountain
    View, Calif. "I'm not only excited, I'm ebullient."

    A decade ago, the idea of searching for intelligent life drew more
    sneers than cheers in some circles. Congress was skeptical. NASA ended
    its small-scale program, leaving the search to private efforts. Now,
    interest is building again.

    One factor is scientific opportunity. Astronomers are finding a growing
    number of planets around other stars - hinting at a potentially vast
    number of solar systems in the galaxy. NASA is planning two telescopes
    specifically designed to look for Earth-like planets outside our solar
    system, which could allow for more-targeted searches.

    Another factor is rising technological horsepower. From cheaper, faster
    computers to devices better able to detect and process extremely weak
    signals, technologies are allowing researchers to expand their searches
    beyond radio waves and visible light. At least two new ground-based
    telescopes are under construction dedicated to the search for
    extraterrestrial intelligence (SETI). In August, top SETI scientists
    will meet at Harvard University to look at potential new projects.

    Yet for all their efforts, scientists have come up empty-handed. But
    even that serves as a goad.

    "The fraction of the galaxy we've searched ... is incredibly small,"
    Dr. Cullers says - perhaps 700 sunlike stars out of billions. "If we
    tie ourselves to the growth of computing, within half a century the
    search will be billions of times larger than it is today."

    When US astronomer Frank Drake first turned a radio dish to the heavens
    to listen for ET signals in 1960, he tuned in only one channel, says
    Dan Werthimer, an astronomer and SETI pioneer at the University of
    California at Berkeley's Space Sciences Laboratory. In the 1970s, new
    receivers could monitor 100 channels at once; today, astronomers can
    monitor roughly 168 million channels simultaneously - and the number
    doubles every year, he adds.

    New clout

    The field is also finding new respectability. In its latest 10-year
    survey of key questions in astronomy and astrophysics and the
    experiments needed to answer them, a National Research Council panel
    listed a telescope being built by the SETI Institute and UC Berkeley as
    a project worth supporting. Although the panel has endorsed SETI
    efforts in previous reports, its 2001 document was the first to endorse
    a private, nonprofit SETI effort.

    Moreover, NASA - which ended its own SETI project in 1993 after it
    raised some eyebrows in Congress - has included one of the SETI
    Institute's scientists in its virtual Astrobiology Institute.

    "SETI was once a four-letter word around NASA headquarters," Cullers
    says. Now SETI researchers can compete for research money "under the
    same conditions as everyone else."

    High on the list of projects is the Allen Telescope Array, a new type
    of radio telescope being designed for the Hat Creek observatory site
    run by the University of California at Berkeley. When completed, the
    facility will boast 350 linked dishlike antennas covering a hectare, or
    about 2.5 acres. Sophisticated electronics will allow observers to
    study signals from different objects simultaneously within the
    antennas' field of view. Thus, SETI astronomers can search the sky
    around the clock for signals from E.T. while other astronomers study
    interstellar clouds, hunt for dark matter, or pursue other objectives.

    In March, former Microsoft executive Paul Allen announced that he was
    contributing $13.5 million toward the facility's expansion. An initial
    Paul G. Allen Foundation donation of $11.5 million is funding the first
    32 antennas, expected to be installed and operating by the end of the
    year. This latest announcement covers another 174 dishes - if the SETI
    Institute and the Berkeley lab building the array can raise $16 million
    in matching funds.

    The facility is of broad interest to radio astronomers in general
    because it represents an American entry in an international design
    competition for an even bigger array of radio telescopes covering
    nearly 250 acres. The Square Kilometer Array is slated to begin
    operating in 2020, after scientists select the site for the observatory
    and pick the technology that will be used. The Allen Telescope Array
    represents a major step forward, allowing SETI scientists to search up
    to 1 million stars in a fraction of the time it would take using
    single-observer telescopes.

    Cullers notes that current research goals include giving radio-based
    SETI projects an ability to look for signals simultaneously in a range
    of different transmission modes - including more complex signals, such
    as those used by cellphones.

    If radio has been the preferred approach for seeking out other
    civilizations in the galaxy, researchers also have started looking for
    various forms of light as a medium of communication.

    Laser bursts represent one possibility, says Paul Horowitz, a physics
    professor at Harvard University who is hunting for E.T. with optical
    telescopes. With 20th-century earthbound technology, he points out,
    it's possible to take the most powerful lasers, generate a pulse
    lasting only a billionth of a second or so, then send it "backwards"
    through a large telescope. Viewed from afar, such a burst would be
    5,000 times as bright as the sun. Because light from the laser and from
    the star dims at the same rate, "if you can see the star, you can see
    the flash," he says.

    Up to now, he and his colleagues at Harvard and Princeton University
    have observed 15,000 stars and come up empty. But they now are building
    a 72-inch telescope that will allow them to survey large patches of sky
    at a time. They plan to begin operating the telescope - funded by a
    $350,000 grant from the Planetary Society in Pasadena, Calif. - within
    a year. Other teams at facilities such as the Lick Observatory in
    California are also running more selective searches.

    One wavelength of emerging interest lies in infrared light, which falls
    just below visible light on the electromagnetic spectrum. Looking in
    that wavelength regime was first proposed by Freeman Dyson of the
    Institute for Advanced Study in Princeton, N.J. In 1959, he suggested
    that advanced civilizations might build orbiting habitats and
    solar-power stations that formed a "shell" around a star at a distance
    that matched that of the civilization's home planet. Such a "Dyson
    Sphere" would emit large amounts of infrared radiation, giving the star
    the appearance of emitting too much infrared light.

    Irradiating civilization?

    At the time, it sounded like an intriguing approach. But astronomers
    have since learned that sunlike stars - especially those with disks of
    dust and gas surrounding them - can appear to generate too much
    infrared radiation for their type.

    Dr. Werthimer and colleague Charles Conroy have taken an initial crack
    at looking for excess IR by picking sunlike stars that are too old to
    have protoplanetary disks. Instead of bidding for precious telescope
    time, they mined data archived from surveys taken by ground- and
    space-based infrared telescopes.

    While they found 32 stars that might have been Dyson Sphere candidates
    based on infrared readings alone, they found no unusual radio emissions
    or light pulses from 20 of the stars observed at the Arecibo Radio
    Telescope in Puerto Rico or from 25 of the stars viewed at optical
    observatories.

    Other scientists are contemplating the possibility of searching for
    pulses from infrared lasers. Such lasers might be a preferred means of
    sending signals or setting up beacons across the galaxy because the
    light penetrates interstellar dust that can block visible light,
    researchers say.

    Trying to expand efforts to cover a range of wavelengths and
    transmission types as the technology becomes available may seem like
    casting good money after bad. But limiting searches to one form of
    communication or to one type of search strategy is futile, Werthimer
    counters. "It's naive to think we know exactly what E.T. is doing."

    Is anybody out there?

    * From 1947 to 1969, the US Air Force studied UFOs under Project Blue
    Book, headquartered at Wright-Patterson Air Force Base in Ohio. Of
    12,618 total sightings reported to Project Blue Book, 701 remain
    unidentified.

    * During several space missions, NASA astronauts reported phenomena
    they could not explain; NASA later determined that, in the context of
    space, none of the observations could be termed abnormal.

    * Congress ended funding for NASA's High Resolution Microwave Survey in
    1993; as a result, SETI launched the private nine-year Project Phoenix,
    which ended in March.

    * Project Phoenix searched more than 750 nearby stars for radio signals.

    Sources: NASA, SETI


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