Is the Rocky Alien Planet Gliese 581d Really Habitable?
A rocky alien planet called Gliese 581d can be the first known beyond the world capable of supporting life as we know Earth, a new study suggests.
Astronomers make a new modeling study of the atmosphere have discovered that the planet is probably in the "habitable zone" of its parent star - who go just to the right of the distances that allow liquid water to exist. The alien world could be similar to Earth in a fundamental way, harboring oceans, clouds and rainfall, according to research.
This conclusion is consistent with other recent models. But not definitively establish that life-sustaining water flowing through the planet's surface.
The new study is that Gliese 581d, which is about seven times more massive than Earth, has a thick atmosphere, carbon dioxide-based. That is very possible on a planet so big, the researchers said, but it is a fact.
The Gliese 581 system: worlds of possibilities
Gliese 581d of parents, known as Gliese 581, is a red dwarf star located 20 light years from Earth, just a stone's throw in the cosmic scheme of things. So far, astronomers have detected six planets orbiting the star, Gliese 581d is not the only intriguing for scientists to think about the possibility of life beyond Earth.
Another planet in the system, called Gliese 581g is approximately three times more massive than Earth, and is most likely a rocky world. This planet received much attention when his discovery was announced in September 2010 and is located right in the center of the habitable zone. That makes 581g an ideal candidate for liquid water and life as we know - if the planet exists.
Some researchers question the analysis to find the planet, and say they can not confirm 581g in follow-up studies. discoverers of the planet, however, are standing by their findings. [The Strange Alien Planet]
Gliese 581d outside the orbits of 581g, far enough from its star than researchers believed that too cold for life when it was originally discovered in 2007. However, a strong greenhouse can be heated 581d substantially increased, perhaps enough to sustain liquid water.
That's the tentative conclusion that the new study and other recent studies by different research teams, which is also possible to model the atmosphere of Gliese 581d.
Modeling alien atmosphere
The planet Gliese 581d receives less than one third of solar energy than Earth is from our sun, and may be tidally locked (a situation in which one side of the world always faces its sun - a permanent day - and the other gives the back, causing the eternal night.)
After the discovery of Gliese 581d is generally believed that any atmosphere thick enough to keep the planet cool hot enough on the night side to freeze completely, ruining any prospect of a habitable environment, researchers say.
The research team tested this possibility in the new study, the development of a new type of computer model that simulates environments alien planets' and surfaces in three dimensions. The model is similar to those used to study climate change on Earth.
When the team ran the model, they found that Gliese 581d, probably made can hold liquid water if it has a dense atmosphere of carbon dioxide. Although the planet is relatively far from the dim red dwarf parent star, may be warmed by the greenhouse effect, with the heat during the day circulated around the globe by the atmosphere.
The team, led by scientists at the Laboratory of Metrology Dynamique (CNRS / UPMC / ENS / Ecole Polytechnique) at the Institute Pierre Simon Laplace, Paris, France, published their findings in The Astrophysical Journal Letters.
The work is still speculative.
To determine conclusively whether Gliese 581d is actually habitable, future work will probably need to detect and characterize the atmosphere directly. And that is likely years away, as it requires the development of new and advanced telescopes. probes by man will not get the planet in the short term, with current technology, it would take hundreds of spacecraft for thousands of years to make the journey of 20 light years.
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