First signs of water seen on planet outside solar system
Email this storyPrint this story 5:00AM Thursday April 12,
2007
WASHINGTON - Evidence of water has been detected for the first time
in a planet outside this solar system, an astronomer says.
The find is tantalising for scientists eager to know whether life
exists beyond Earth.
Travis Barman, an astronomer at Lowell Observatory in Flagstaff,
Arizona, said water vapour had been found in the atmosphere of a
large, Jupiter-like gaseous planet located 150 light years from
Earth in the constellation Pegasus. The planet is known as HD
209458b.
Other scientists reported in February that they were unable to find
evidence of water in this planet's atmosphere, as well as another
Jupiter-like planet.
"I'm confident," Mr Barman said. "It's definitely good news because
water has been predicted to be present in the atmosphere of this
planet and many of the other ones for some time."
Lowell Observatory, a privately owned astronomical institution,
said the research, which has been accepted for publication in the
Astrophysical Journal, was backed by Nasa.
The detection of the presence of water vapour was possible because
this planet, from the vantage point of Earth, orbits directly in
front of its star every 3 1/2 days, allowing crucial measurements
to be made. It is what is known as a transiting planet.
Scientists searching for signs of life beyond Earth are keen to
learn about the presence of water on other planets - in and beyond
this solar system - because water is thought to be fundamental to
the existence of life.
Mr Barman noted that a Jupiter-like gaseous planet such as this
one, as opposed to a rocky one like Earth, was highly unlikely to
harbour life, saying the finding about water vapour in its
atmosphere did not answer one way or another questions about the
existence of extraterrestrial life.
The findings "are not adequate to really address a question as deep
and profound as the existence of life elsewhere. We're not there
yet.
"Certainly this is part of that puzzle - understanding the
distribution of water in other solar systems is important for
understanding whether or not conditions for life are possible. The
presence of water does not exclude the possibility of life but it
doesn't mean it's there, either."
Mr Barman said his findings did provide good reason to believe
other planets beyond this solar system also had water vapour in
their atmospheres.
Water has been found elsewhere in this solar system such as in
large deposits of ice at the north and south poles of Mars.
Planet HD 209458b was also the first planet outside this solar
system found to have an atmosphere.
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