Smallest Earth-like planet found

Wednesday, 25 January 2006, 18:02 GMT

Smallest Earth-like planet found
By Rebecca Morelle
BBC News science reporter

Scientists used the microlensing technique to find the new planet
An international team of astronomers has found the smallest Earth-like
planet yet outside our Solar System.

The new planet has five times the Earth's mass and can be found about
25,000 light-years away in the Milky Way, orbiting a red dwarf star.

The discovery, reported in the journal Nature, was made using a method
called microlensing, which can detect far-off planets with an Earth-like
mass.

The planet's cold temperatures make the chance of finding life very
unlikely.

The planet, which goes by the name OGLE-2005-BLG-390Lb, takes about 10
years to orbit its parent star, a red dwarf which is similar to the Sun
but cooler and smaller.

It is in the same galaxy as Earth, the Milky Way, but is found closer to
the galactic centre.

Like Earth, it has a rocky core and probably a thin atmosphere, but its
large orbit and cool parent star mean it is a very cold world.

Predicted surface temperatures are minus 220 degrees Celcius (-364F),
meaning that its surface is likely to be layer of frozen liquid. It may
therefore resemble a more massive version of Pluto.

"This is very exciting and important," said Professor Michael Bode from
Liverpool John Moores University, a principal investigator for the
RoboNet project which collaborated on this research.

"This is the most Earth-like planet we have discovered to date, in terms
of its mass and the distance from its parent star," he told BBC News.

"Most of the other planets that have been discovered are either much
more massive, much hotter or both."

The microlensing technique used to find this planet was first predicted
by Albert Einstein in 1912.

Microlensing occurs when a massive object in space, like a star, crosses
in front of another more distant star.

As it passes, the gravity from the foreground object bends the light
coming from the background star, temporarily making it look brighter.
This usually lasts for about a month.

How can we prove there is life on a distant planet when we have
problems seeing if there is life on Mars?

Dr Martin Dominik, University of St Andrews

If the foreground star has a planet orbiting it, it will distort the
light even more, and will make the star behind it look even brighter.
But this effect lasts for a much shorter period, giving astronomers just
hours or days to detect it.

Dr Martin Dominik from the University of St Andrews is a co-leader of
the PLANET collaboration, one of the microlensing networks used to
detect the new planet.

"We first saw the usual brightening reaching a peak magnification on 31
July 2005. On 10 August, however, there was a small 'flash' lasting
about half a day," he said.

"By succeeding in catching this anomaly with two of the telescopes of
our network and with careful monitoring, we were able to conclude that
the lens star is accompanied by a low-mass planet."

The discovery was the joint effort of three microlensing campaigns,
PLANET/RoboNet, OGLE and MOA, and involved researchers from 12
countries.

So far, about 160 planets have been found outside our Solar System, but
only three of them have been located using the microlensing technique.

Recent simulations of planet formation suggest that bodies with an
Earth-like mass are abundant. Scientists are attempting to discover more
new worlds using this technique and are looking for ways to refine it
further.

Dr Nicholas Rattenbury, from Jodrell Bank Observatory in Liverpool, a
member of the MOA microlensing collaboration, points out: "We could take
this research forward by building a network of bigger telescopes around
the world to make us more efficient at detecting these Earth-like
planets."

If planets are found with conditions similar to our own planet, then the
next step would be to begin the search for life, but this might not
prove easy.

"To prove there is life on a far-off planet would be difficult," Dr
Dominik told the BBC News website.

"How can we prove there is life on a distant planet when we have
problems seeing if there is life on Mars?"
End Quote

What they aren't telling you about DNA profiles
and what Special Branch don't want you to know.
http://www.nutteing2.50megs.com/dnapr.htm
was on http://www.nutteing.50megs.com/dnapr.htm
or nutteingd in a search engine.

Valid email (remove 4 of the 5 dots)
Ignore any other apparent em address used to post this message -
it is defunct due to spam.



--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG