Andrew Yee[_1_]
June 12th 07, 03:59 AM
Potsdam Institute for Climate Impact Research
Potsdam, Germany
Contact:
Werner von Bloh, Potsdam Institute for Climate Impact Research (PIK),
Germany
phone: +49 (0)331 288 26 03
Press Office:
Uta Pohlmann, phone: +49 (0)331 288 25 07
11 June 2007
Surprise during the Search for a Second Earth
Potsdam -- A team of scientists led by the Potsdam Institute for Climate
Impact Research (PIK) investigated the habitability of the planetary system
Gliese 581 in the constellation of Libra, 20 light-years away. With the help
of a model for the evolution of Earth-like planets coupled with a climate
model they were able to demonstrate habitable conditions on the planet Gl
581d, while its smaller brother, Gl 581c, has to be classified
uninhabitable.
This contradicts the findings of another research team in April of this year
that announced Gl 581c to be the first habitable planet outside our solar
system.
The new investigations of the Potsdam scientists Werner von Bloh, Christine
Bounama and Siegfried Franck together with Manfred ****z from the Texas
University at Arlington incorporate the thermal evolution of planets, i.e.
the cooling of the planetary body from its formation and the connected
geodynamic parameters. Because of its heavy mass the Potsdam scientists
consider it likely that Gl 581c has a dense atmosphere. Previous
calculations derived the habitability of the planet only from temperatures
calculated for the radiation balance of the planetary surface without an
atmosphere.
The planetary system Gliese 581 contains probably three planets orbiting a
Red Dwarf. The central star has 100 times less luminosity than our Sun. Both
planets investigated are so-called Super-Earths, i.e. planets with a mass up
to 10 times higher than that of the Earth.
Among the extrasolar planets detected so far, the planet Gl 581c, already
acclaimed by the media as a "second Earth", has the most similar dimensions
compared to Earth, because it has "only" five times its mass. But according
to the new calculations the orbit is too close to the central star so that
the surface is too hot for the evolution of life.
In contrast to previous assumptions, the environmental conditions on the
planet Gl 581d with an eight times higher mass than Earth and a more distant
orbit could allow the evolution of primitive life forms. Because the planet
always has the same side turned towards its central star -- as the Moon does
to the Earth -- the emergence of higher life forms is very unlikely. On the
day side it is probably warm, while on the night side severe cold dominates.
Nor could Gliese 581d become a second home planet for mankind because even
on its sunlit side, red twilight prevails and wild storms blow.
The search for a "second Earth" able to harbor higher life forms is
therefore still far from over. Nevertheless, a more detailed investigation
of Gl 581d would be exciting because it orbits in the habitable zone, where
the emergence of life might be possible. This planet and its neighbors are
within the range of detection of the Darwin satellite mission planned by the
Europeans for 2015, a mission designed for the observation of extrasolar
planets and the detection of life. The Super-Earth Gl 581d should be
explicitly observed as part of this endeavor.
More information:
* Article
http://arxiv.org/abs/0705.3758v1
* Homepage of Research Project
http://www.pik-potsdam.de/PLACES
Potsdam, Germany
Contact:
Werner von Bloh, Potsdam Institute for Climate Impact Research (PIK),
Germany
phone: +49 (0)331 288 26 03
Press Office:
Uta Pohlmann, phone: +49 (0)331 288 25 07
11 June 2007
Surprise during the Search for a Second Earth
Potsdam -- A team of scientists led by the Potsdam Institute for Climate
Impact Research (PIK) investigated the habitability of the planetary system
Gliese 581 in the constellation of Libra, 20 light-years away. With the help
of a model for the evolution of Earth-like planets coupled with a climate
model they were able to demonstrate habitable conditions on the planet Gl
581d, while its smaller brother, Gl 581c, has to be classified
uninhabitable.
This contradicts the findings of another research team in April of this year
that announced Gl 581c to be the first habitable planet outside our solar
system.
The new investigations of the Potsdam scientists Werner von Bloh, Christine
Bounama and Siegfried Franck together with Manfred ****z from the Texas
University at Arlington incorporate the thermal evolution of planets, i.e.
the cooling of the planetary body from its formation and the connected
geodynamic parameters. Because of its heavy mass the Potsdam scientists
consider it likely that Gl 581c has a dense atmosphere. Previous
calculations derived the habitability of the planet only from temperatures
calculated for the radiation balance of the planetary surface without an
atmosphere.
The planetary system Gliese 581 contains probably three planets orbiting a
Red Dwarf. The central star has 100 times less luminosity than our Sun. Both
planets investigated are so-called Super-Earths, i.e. planets with a mass up
to 10 times higher than that of the Earth.
Among the extrasolar planets detected so far, the planet Gl 581c, already
acclaimed by the media as a "second Earth", has the most similar dimensions
compared to Earth, because it has "only" five times its mass. But according
to the new calculations the orbit is too close to the central star so that
the surface is too hot for the evolution of life.
In contrast to previous assumptions, the environmental conditions on the
planet Gl 581d with an eight times higher mass than Earth and a more distant
orbit could allow the evolution of primitive life forms. Because the planet
always has the same side turned towards its central star -- as the Moon does
to the Earth -- the emergence of higher life forms is very unlikely. On the
day side it is probably warm, while on the night side severe cold dominates.
Nor could Gliese 581d become a second home planet for mankind because even
on its sunlit side, red twilight prevails and wild storms blow.
The search for a "second Earth" able to harbor higher life forms is
therefore still far from over. Nevertheless, a more detailed investigation
of Gl 581d would be exciting because it orbits in the habitable zone, where
the emergence of life might be possible. This planet and its neighbors are
within the range of detection of the Darwin satellite mission planned by the
Europeans for 2015, a mission designed for the observation of extrasolar
planets and the detection of life. The Super-Earth Gl 581d should be
explicitly observed as part of this endeavor.
More information:
* Article
http://arxiv.org/abs/0705.3758v1
* Homepage of Research Project
http://www.pik-potsdam.de/PLACES