• E-mail
• Print
• Comment
• Font Size
• Digg
• del.icio.us
• Discuss article

Science & Technology: STARS & PLANETS

Posted on: Wednesday, 28 July 2004, 06:00 CDT

THE HUNT for life in the Universe has shifted into a higher gear - with the backing of a powerful alliance of scientists of all kinds that includes astronomers, geologists, chemists, biologists and experts in intelligence. This was a central message from a conference on Bioastronomy, held in Iceland this month.

A few years ago, such conferences were very much the province of the Seti (Search for Extraterrestrial Intelligence) community. They are the folks who are "listening out" for a radio signal from an alien intelligence. Although they have widened the search by now looking for signals conveyed by light or other radiations, the Seti researchers have still - after 40 years - failed to pick up that phone call from ET.

But the success of Seti depends on the aliens actually bothering to send out a powerful signal into space. Suppose, instead, that ET is the strong silent type? That's where the new initiative comes in.

First, astronomers are looking for planets beyond the solar system. And there is good news here. Over the past decade, 123 planets have been found circling other stars. Almost all of these are heavyweight gas giants, like Jupiter in our solar system but these new planetary systems presumably include smaller planets like the earth.

The conference heard how most of these planetary systems have a "habitable zone", where an earth-like planet would not be thrown out by the known giant planets, and where water would be liquid for billions of years - long enough for life to evolve.

Life might also arise on a watery moon that orbits a giant planet. It would be a scaled up version of Jupiter's moon Europa, which is warmed by volcanic heat and capped by a layer of ice. If the aliens are living on such water or ice worlds, they would presumably have some difficulty in building radio transmitters for Seti communications.

The next stage in planet hunting will come from Nasa's Kepler satellite (pictured). To be launched in 2007, Kepler will look for stars that dim briefly, as a planet passes in front. The telescope on Nasa's follow- up, the Terrestrial Planet Finder Coronagraph, will block out the light of the star itself, and see the faint planet nearby. And the European Space Agency's Darwin mission will use several telescopes, flying in formation, to see planets even more clearly.

In the meantime, biologists are discovering that life might evolve even on planets quite different from earth. Iceland - with its icecaps and boiling geysers - was an appropriate locale for the discussion on bacteria that thrive below freezing point of water, and others that enjoy temperatures up to 121C.

The British evolutionary biologist Simon Conway pointed out that the aliens - if they exist - were not going to be "chaps with green ears" and cautioned that alien intelligence is probably something so different and so remarkable that we cannot even imagine it. Instead of just listening for patterns in radio signals, scientists should be looking for "anomalies" of any kind in the universe.

What's Up

The evening sky is dominated by the great Summer Triangle of bright stars. Almost overhead is blue-white Vega, the leading star of the small constellation of Lyra (the lyre). To the left of Vega you'll find Deneb, in Cygnus (the swan). The third star shines lower in the sky: Altair, the brightest star of Aquila (the eagle). To its lower right you'll find the red star Antares, marking the heart of Scorpius (the scorpion). There's an unusual dearth of bright planets in the evening sky. But that's more than compensated for around 2am, when brilliant Venus rises in the northeast. It's currently 10 times brighter than any of the stars.

As the dawn glow begins to light up the sky, you'll find Saturn much lower down to the left of Venus and some 50 times fainter. As the month goes by, the two planets will draw together and reach their closest on the night of 31 August/1 September.

Throughout early and mid August you'll spot shooting stars from the Perseid display of meteors. They are fragments of a comet called Swift Tuttle, seeming to emanate from the constellation Perseus as they burn up in the earth's atmosphere. The maximum is due on the morning of 12 August, after sunrise as seen from the UK. But two comet astronomers, Esko Lyytinen from Finland and Tom Van Flandern in Washington, predict there will be an extra stream of fragments that may create a burst of shooting stars the previous evening at around 10pm on 11 August - an ideal time to see them from this country.

More News in this Category