[Paleopsych] NYT: Hunting for Life in Specks of Cosmic Dust

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Tue Jul 19 19:31:56 UTC 2005

Hunting for Life in Specks of Cosmic Dust


    In astronomy, the race is on to the bottom.

    Teams of astronomers are staying up all night in the breath-fogging
    cold of the high-altitude desert of Chile and in the oxygen-starved
    heights of Hawaiian volcanoes, deciphering downloaded pixels from the
    Hubble and Spitzer Space Telescopes over soggy pizza, and then
    upstaging one another's news conferences, all in the search for the
    smallest, dimmest crumbs of creation, the most mundane specks of dust
    that may be circling some garden-variety star.

    It is here, in boring, peaceful meadows of the galaxy, far from
    fountains of lethal high energy particles, swarms of killer comets or
    hungry black holes, we are told, that we should look if we want to
    find habitable abodes and possibly life.

    And that, of course, would be the most exciting and wonderful result
    in the history of science, one of the few in astronomy that would
    probably rebound beyond science, affecting our view of our own status
    as tenants in this strange house of stars.

    Last spring the quest ratcheted another notch downward (or upward)
    when a team of astronomers announced the detection of a planet only
    seven times the mass of the Earth circling a dim star named Gliese 876
    in the constellation Aquarius. This was the first alien planet that
    astronomers were unabashedly able to identify as a ball of rock, like
    the Earth, rather than a bag of gas like Jupiter or Neptune.

    Its discoverers estimated that the new planet was made of iron and
    silicate and was about 70 percent larger in diameter than Earth.
    Moreover, as in our own solar system, there are larger Jupiter-size
    planets orbiting Gliese 876 at greater distances.

    Never mind for the moment that it was so close to its home star,
    Gliese 876, that you could bake a lasagna on its surface. The planet
    was hailed as yet another sign that the cosmos was basically friendly
    and that sooner or later planet hunters would find worlds as small as
    Earth out there, another step on the road to finding out whether or
    not humanity is alone in the universe.

    "We are beginning to find our planet's kith and kin among the stars,"
    said Geoffrey Marcy of the University of California, Berkeley, leader
    of the team that discovered the Gliese planet.

    And the joy of family reunion has resounded throughout the cosmos of
    astronomers for more than 10 years now.

    It was on the night of July 4, 1995, that Michel Mayor and his student
    Didier Queloz woke up their wives at 4 a.m. to drink Champagne and eat
    raspberry pie at an observatory in the south of France. The
    astronomers, based at the University of Geneva, had just confirmed
    that an invisible object about half the mass of Jupiter was sailing
    around the star 51 Pegasi, tugging it to and fro every four days. It
    was the first planet ever discovered around another Sun-like star.

    Dr. Mayor and his student were using a humble little-used reflector a
    mere 76 inches in diameter, way small compared with the 320-inch
    behemoths then being planned and built for cosmology. Their rivals,
    Dr. Marcy and Paul Butler, professors at San Francisco State, had to
    make do with similarly unglamorous circumstances at Lick Observatory.
    "We were typically assigned only two nights per year, exactly when the
    Moon was full and no one wanted the telescopes," Dr. Marcy recalled in
    an e-mail message.

    Most of the 150 so-called exoplanets subsequently discovered have been
    found using the "wobble" technique that Dr. Mayor's group and Dr.
    Marcy's group pioneered. This consists of looking for a to-and-fro
    motion in the star, induced by the gravitational tug of an orbiting

    In retrospect, it seems only natural that the first planetary systems
    these astronomers discovered were psychotic beasts unlike anything
    previously imagined. The more massive a planet is and the more tightly
    it circles its star, the bigger the wobble and thus the easier it is
    to detect. As a result, the first planets were so-called "hot
    Jupiters," orbiting their suns in a matter of days instead of years,
    lethally searing and dense.

    As time has gone on and they gather more data on various systems, the
    observers have been able to detect smaller planets and ones that are
    farther and farther from their stars, an effect astronomers refer to
    as "drawing back the curtain."

    Last week astronomers announced the discovery of a planet with three
    suns, in a configuration the theorists had thought was unlikely, if
    not impossible. Dr. Marcy said in an interview that when the dust
    finally settled he expected that planetary systems with architectures
    like our own - with Jupiter-mass planets in circular outer orbits,
    leaving space for smaller planets in closer orbits protected from
    comet showers - would be rare, "but not that rare."

    Whether those planets will be suitable for life and intelligence is a
    different matter, however, and one that reaches beyond astronomy into
    metaphysics and theology. The requirements for Life As We Know It,
    some astronomers argue, are so exacting that Goldilocks planets like
    Earth might be rare or even nonexistent.

    The list of astronomical requirements for life gets longer and more
    exacting every year: the home star has to be far enough from the
    galactic center to be away from lethal black hole pyrotechnics, for
    example, but not so far into the galactic sticks that stellar
    evolution has not yet produced enough of the heavier elements like
    oxygen and iron needed for planets and life.

    Among other things, its planet has to have liquid water, a magnetic
    field to keep away cosmic rays, plate tectonics to keep things
    stirred, a giant outer planet to keep away comets and asteroids and
    perhaps a big moon to stabilize its rotation axis.

    Of the 200 billion or so stars in the galaxy, what fraction have the
    lucky combo to win this cosmic lottery? Faced with the same paltry
    data, different astronomers get vastly different conclusions, ranging
    from hundreds of thousands to one, namely our own.

    Among the various members of the planetary posse, Frank Drake, an
    astronomer at the SETI Institute and a pioneer of the practice of
    listening with radio telescopes for alien broadcasts, is one of the
    most optimistic.

    "It may well be that there are far more habitable planets orbiting M
    dwarfs than orbiting all other types of stars combined," he said on
    the institute's Web site recently, referring to the dim red stars like
    Gliese 876. The SETI Institute is holding a conference this week on
    the habitability of planets belonging to such stars.

    On the other hand are pessimists who argue that planets like the Earth
    and therefore even simple life forms are rare. One is Ben Zuckerman,
    an astronomer and exoplanet hunter at the University of California,
    Los Angeles, who admitted in an e-mail message, "Frankly, the correct
    answer remains anyone's guess, and the range of guesses is very wide

    But, he emphasized, the question can actually be answered by future
    spacegoing experiments like the Terrestrial Planet Finder and Kepler,
    which will find and count habitable planets in our corner of the

    A null result would suggest that humans might be alone in the galaxy
    or the universe.

    This would merely be an interesting academic argument except for a
    film that is going around, and which I recently viewed, called "The
    Privileged Planet," which suggests that the Earth's nice qualities are
    no accident.

    The film, produced by Illustra Media in California, is based on a book
    of the same name by Guillermo Gonzalez, an astronomer at Iowa State,
    and Jay W. Richards, a philosopher and vice president of the Discovery
    Institute in Seattle.

    It argues that Earth is so special and unlikely that it must be the
    work of an intelligent designer. "What if it's not a cosmic lottery?"
    Dr. Richards asks in the film.

    The Discovery Institute advocates "intelligent design," a notion that
    posits the intervention by a designer, whether divine or not, in the
    origin and history of life, as an alternative to standard evolutionary
    biology. Illustra Media has produced a series of videos in support of
    this idea.

    The showing of the film at the Smithsonian Museum of Natural History
    last month exacerbated the worries of many astronomers that the Big
    Bang would be next on the hit list of creationists.

    Thoughtful cosmologists have long wondered about the apparent
    friendliness of the universe to carbon-based life forms like us. The
    notion that the fix must be in from a creator, however, has always
    been rejected as unscientific thinking.

    It's the job of scientists, after all, to pursue natural causes and
    explanations, not settle for supernatural ones.

    One such explanation for the specialness of the Earth, for example,
    comes from theories of modern particle physics and cosmology, which
    seem to suggest that there have been many, many Big Bangs resulting in
    a plethora of universes. We live in one that is suitable for us the
    same way that fish live in the sea.

    A prominent cardinal in the Catholic Church, Christoph Schönborn,
    recently criticized this idea, along with evolution, in a July 7
    article on the Op-Ed page of The New York Times. He said the church
    needed to "defend human reason" against "scientific claims like
    neo-Darwinism and the multiverse hypothesis in cosmology invented to
    avoid the overwhelming evidence for purpose and design found in modern

    But the argument from design, many scientists say, is circular.
    Charles Stevenson, a planetary scientist at Caltech, said that it was
    no surprise that the Earth appears suited to our needs. "That's what
    Darwinian evolution tells us should happen. We are adapted to our
    world," Dr. Stevenson said.

    Who knows what powers atoms in their collective and complex majesty
    have to respond to their environments over time?

    Lacking anything approaching a final theory of physics, or of how
    planetary systems form, and of more than one example of life - the
    biosphere on Earth - scientists have no way of actually knowing how
    unlikely various properties of life and the universe are. In science
    the smart money is always on surprise.

    Everybody agrees that intelligent technological life is a much greater
    leap, but it might be instructive to consider who is laying down bets
    on at least looking for it. Among the financial angels of the search
    for extraterrestrial intelligence, or SETI, have been people like Paul
    Allen, the co-founder of Microsoft; the late Barney Oliver, William
    Hewlett and David Packard, leaders of Hewlett-Packard; Gordon Moore,
    the founder of Intel; and the novelist Arthur C. Clarke, who invented
    the idea of the communications satellite.

    The smart money isn't always right, but this is certainly smart money.

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