From: | ISCNI*Flash |
Title: | ANOTHER PLANET FOUND AROUND DISTANT STAR |
Source: | San Jose Mercury News |
Date: | Feburary 11, 1996 |
announced the discovery of yet another -- this one nine times the mass of
Jupiter -- that signals a new frontier of astronomy.
To the cheers of a capacity 800-person crowd attending his lecture at
Foothill College [near Palo Alto, California] on February 9, Marcy laid a
transparency on an overhead projector showing data gathered from Lick
Observatory's 120-inch telescope and analyzed earlier that day.
"This is a new class of planets -- I even hate to use that term -- this may
be a new beast... This is a new frontier," Marcy said.
This planet marks the fourth discovered using a phenomenon known as the
Doppler effect that measures a star's wobble caused by the gravity of a
nearby object.
The new planet, found orbiting a star in the Milky Way known as HD 114762,
has an eccentric or egg-shaped orbit and takes 87 days to orbit its star.
Marcy, who has become accustomed to rocking the astronomical world since his
and colleague Paul Butler's discoveries last month of two new planets, said
that he was especially excited by this discovery because it proves that a
planet they discovered orbiting the star 70 Virginis late last year is not a
freak.
Like the one announced on Feb 9, that planet also has several strange
characteristics, including a mass 6.5 times the size of Jupiter, and an
eccentric 116-day orbit.
"When you have two discoveries of similar-type planets, it proves 70 Vir is
not a freak," Marcy said. "We're dealing with a new class of planets."
Marcy explained later that he could not claim discovery of the latest planet
because astronomer David Latham at Harvard University discovered that HD
114762 wobbled back in the late 1980s. Latham, however, lacked instruments
that could break up the light from the stars into colors and determine that a
planet caused the wobble.
"So the research languished until we could use higher-precision instruments
to confirm that a planet did exist," Marcy said, noting that his student Eric
Williams has been analyzing the data for his master's thesis.
Marcy acknowledged that with current instruments, only planets the size of
Jupiter and larger can be detected. But next year, advances in data
collection and tools will allow astronomers to find planets the size of
Saturn.
He was less certain about the possibility of finding intelligent life on
other planets.
"I believe, based on my limited information, that all the stars you see at
night have planets," he said. "Are there terrestrial planets to allow liquid
water to puddle? Let others say whether life exists."
Others are hard at work on that very question. Puzzling radio signals have
been detected from Virginis 70, the very star around which Marcy found his
first planet last year.
The discovery has raised hopes that extraterrestrial civilizations may exist.
However, those responsible for picking up the emissions have cautioned that
there is only a slim chance that an alien broadcaster is behind them.
Nevertheless, the scientists -- based at the University of California at
Berkeley -- say they cannot explain the repetitive nature of some of the
signals from Virginis 70, in the constellation Virgo.
The discovery was made by scientists working on a project called Serendip 3,
part of SETI (Search for Extraterrestrial Intelligence), a privately funded
program. On first learning that a planet had been found orbiting Virginis 70,
the Serendip 3 team searched their records for data that the project might
have received from space near the star. They found one "highly unusual" set
of signals with a repetitive pattern. As a result, they have announced that
they are going to begin a new search of space near the star later this year.
Growing numbers of astronomers now believe that radio signals from alien
civilisations will soon be detected.
"I believe the odds on there being advanced civilisations in our Milky Way
galaxy are a thousand to one on," said Prof. Paul Horowitz of Harvard
University. His team operates an 84-foot radio telescope near Boston that
continually searches the sky for artificial signals.
So far, there have been many false alarms where likely signals have failed to
repeat themselves.
Another astronomer, Prof. Frank Drake, said: "The real signal, when it is
found, will be unmistakable. I strongly believe that we shall find one before
the year 2000."
But other scientists warn that it could be dangerous to advertise our own
presence on Earth by transmitting signals.
Prof. Robert Rood of Harvard said: "The civilisation that blurts out its
existence on interstellar beacons at the first opportunity may be like some
early hominid descending from the trees and calling 'Here, kitty' to a
sabre-toothed tiger."