SCIENCE fiction teleserials like Star Trek
may not be gifts of over-stretched imagination, after all. Two independent
sightings of a planet around a sun-like
star dispel the notion that our solar system is unique. This has freshly fuelled
inquiries into the possibility of extraterrestrial life-forms.
The star, 51 -Pegasus, is eight billion
years old and 40 light-years away and is
visible to the naked eye from earth's
northern hemisphere. The new-found
planet revolves around it in four days,
less than five million miles from it,
skimming the star's outer surface where
temperatures reach roughly 1800oF.
Reports of the first siting, by Michel
Mayor and Didier Queloz of the Geneva
Observatory in Switzerland, on October
6, met with much skepticism. But after a
four-day study scientists at the Lick
Observatory near San Jose, California,
confirmed this.
After hearing about the Swiss study,
Geoffrey Marcy, professor of Physics
and Astronomy at the San Francisco
University, and Paul Butler, post-doctoral researcher at the University of
California, Berkeley, made independent
measurements of the 5 1 -Pegasus system.
Because it is revolving very close to
the star, the planet is lost in the glare of
the star's dazzling light and therefore
not normally visible. During the obserations by the American scientists,
which took four days, that is, the time in
which the planet completes one revolution, the doppler's shift in the star's light
was measured. The normal light spectrum experienced a wobble in the star's
motion caused by the planet's gravitational pull. Says Marcy, "It pushes the
star around like nothing we've seen".
As of now, the scientists do not
know what the planet is comprised of -
solids or gases, whether it is accompanied by other planets or is a solitary
wanderer. They are also not sure about
the origin of the planet. One possibility
being investigated is that of the planet
being thrown towards the mother star
in a collision or a near-collision with
another planet. The American scientists
are carrying out further observations
over a period of 10 days to find answers
to some of these questions.
Until now, the only accepted planets
were those belonging to a dead sun or
pulsar, which is a dense, rapidly spinning remnant of an exploded star. Two
or possibly three such planets were discovered three years ago by Alexander
Wolszczan at the Pennsylvania State
University.
With the weekly magazine Science
News reporting the detection of a large
planet around another star - the GL229
- about 30 light-years from the earth,
scientists are waiting with great anticipation. Says astronomer Douglas
Duncan, of the Adder Planetarium and
the University of Chicago, "Planets are
not easy to find... This is the decade in
which we will find out just how com-
mon planets are."
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