Download The Daily Telegraph – London… 14th February 2008… New Solar

The Daily Telegraph – London…
14th February 2008…
New Solar System Boosts Possibility Of Alien Life…
A planetary system with remarkable similarities to our own has been discovered, potentially
increasing the chances of finding extra-terrestrial life.
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Astronomers have identified two new planets orbiting a star about half the size of our sun
some 5,000 light-years away.
The system, called OGLE-2006-BLG-109L, resembles a slightly scaled down version of our
Solar system because the two gas giant planets are similar sizes relative to their star as
Jupiter and Saturn are to our sun.
The smaller planet is roughly twice as far from its star as the larger one, just as Saturn is
about twice as far from the sun as Jupiter.
Planetary scientists who discovered them believe there could be rocky planets, like
Mercury, Venus, Earth and Mars, closer to the star.
Of around 250 planets so far discovered only 25 are known to be in systems with multiple
planets.
The discovery of OGLE-2006-BLG-109L, highlighted in the journal Science, has excited
astronomers because it suggests there could be large numbers of other planetary systems
which take a similar form to our own.
Researchers searching for extraterrestrial life generally assume the most likely locations will
be rocky planets in the so-called "habitable zone" - the region of a planetary system in which
temperatures would allow water to remain in liquid form.
Keith Horne, Professor of Astronomy at St Andrews University, said: "Here we have a
system where the two largest planets are similar to the two largest in our own system.
"This is something of a surprise. It may indicate that planetary systems like our own are
relatively common.
"Once we know that planets similar to Earth are common, it is straightforward to go ahead
on finding them and investigating whether these harbour any forms of life."
The newly discovered system was identified by a world-wide network of 11 telescopes,
including the UK's Liverpool Telescope on the Canary Islands.
It was found through the use of gravitational microlensing - a method that takes advantage
of the tendency of light rays to bend as they pass close to large objects such as stars.
The gravity of the intervening object warps surrounding space and magnifies light from
objects in the background.
The technique was first proposed by Albert Einstein. For it to work, a star must pass almost
directly between the observer and the planet or star being observed.
Scott Gaudi, assistant professor of astronomy at Ohio State University, said: "Theorists
have wondered whether gas giants in other solar systems would form in the same way as
ours did. This system seems to answer in the affirmative."
Dr Martin Dominik, also of the University of St Andrews, said: "While most planetary
systems around other stars substantially differ from the Solar system, a series of recent
detections have brought us closer and closer to home.
"Sooner rather than later, someone can be expected to discover an Earth-mass planet
orbiting a star other than the sun - and it could be us."