From Daily Mail.
It’s got the same climate as Earth, plus water and gravity. A newly discovered planet is the most stunning evidence that life - just like us - might be out there. The discovery was announced today by a team of European astronomers, using a telescope in La Silla in the Chilean Andes.
The Earth-like planet that could be covered in oceans and may support life is 20.5 light years away, and has the right temperature to allow liquid water on its surface.
The new planet, which orbits a small, red star called Gliese 581, is about one-and-a-half times the diameter of the Earth. It is the first exoplanet (a planet orbiting a star other than our own Sun) that is anything like our Earth. Gliese 581 is among the closest stars to us, just 20.5 light years away (about 120 trillion miles) in the constellation Libra. It is so dim it can be seen only with a good telescope.
It has a mass five times that of Earth, probably made of the same sort of rock as makes up our world and with enough gravity to hold a substantial atmosphere.
Astrobiologists - scientists who study the possibility of alien life - refer to a climate known as the Goldilocks Zone, where it is not so cold that water freezes and not so hot that it boils, but where it can lie on the planet’s surface as a liquid. This new planet lies bang in the middle of the zone, with average surface temperatures estimated to be between zero and 40c (32-102f). Lakes, rivers and even oceans are possible.
The surface gravity is probably around twice that of the Earth and the atmosphere could be similar to ours.
Although the new planet is in itself very Earth-like, its solar system is about as alien as could be imagined. The star at the centre - Gliese 581 - is small and dim, only about a third the size of our Sun and about 50 times cooler. The two other planets are huge, Neptune-sized worlds called Gliese 581b and d (there is no “a”, to avoid confusion with the star itself).
The Earth-like planet orbits its sun at a distance of only six million miles or so (our Sun is 93 million miles away), travelling so fast that its “year” only lasts 13 of our days. The parent star would dominate the view from the surface - a huge red ball of fire that must be a spectacular sight. Its sun is an ancient star - in fact, it is one of the oldest stars in the galaxy, and extremely stable. If there is life, it has had many billions of years to evolve.
This makes this planet a prime target in the search for life. According to Seth Shostak, of the Search for Extraterrestrial Intelligence Institute in California, the Gliese system is now a prime target for a radio search.
The real importance is not so much the discovery of this planet itself, but the fact that it shows that Earth-like planets are probably extremely common in the Universe. There are 200 billion stars in our galaxy alone and many astronomers believe most of these stars have planets.
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Greenhouse Effect May Expand Habitable Planet Roster. (National Geographic News)
In the search for habitable planets around nearby stars, the greenhouse effect blamed for global warming on Earth may not always be bad news.
A French-led group of planetary researchers recently modeled the theoretical effects that a cocktail of “super-greenhouse” gases might have on a recently discovered giant planet.
The team found that the theoretical mixture may warm the planet Gliese 581 d to the right temperature for permanent liquid water, the major criterion of any habitable zone.
Gliese 581: one planet might indeed be habitable. (Physorg)
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