Friday, October 1, 2010

Gliese 581G The New Earth We'll All Soon be Living On - or Not.

Artists depiction of Gliese 581G

Wednesday the University of California, Santa Cruz announced the discovery of two new planets orbiting the red dwarf star known as Gliese 581, located around twenty light years from earth in what we see as the Libra constellation.

The new planets were both discovered using the Doppler method which measures the shift in the wavelength of light being emitted by a star which, changes when tugged on by the gravity of an object orbiting around it. A planet's mass, the shape of its orbit, and it's distance from it's sun, all effect how the light shifts allowing astronomers to devise specific details about distant objects like these two new Exoplanets of which, the most talked about has been designated Gliese 581G.

With a mass of three to seven times that of the Earth, Gliese 581G is the sixth to be identified orbiting Gliese 581 and is the newest planet in the system to be marked as a potential home for life. Unlike Gliese 581C - which is likely too close to it's star and therefore too hot to sustain liquid water or life - and Gleise581D - which is likely to0 far away from the sun and therefore too cold (or maybe not if it has a thick enough atmosphere) - Gliese 581G orbits it's sun in the so called "Goldilocks Zone" making it the most likely contender yet for a planet capable of sustaining life.

Like the rest of the known planets in the system, 581G follows a circular orbit around it's sun, it completes an orbit every 37 days and is, as far as we can tell, the fourth planet from it's sun. Gliese is also tidally locked to it's star. That means one side of the planet is always facing the sun locking it in a state of perpetual daylight , while the other faces away leaving it in total darkness- which would make the line between shadow and light or terminator, the most habitable place on the planets surface. Researchers also estimate the average temperature on the planet to be between -24 and 10 degrees Fahrenheit.

But contrary to the popular take on this story, which professor of astronomy and astrophysics at the University of California, Santa Cruz, Steven Vogt is not helping by saying things like:

"Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent,"

Don't go packing your bags or planning what deep space message you'll be sending to the people of Gliese just yet. While this is an amazing discovery, aside from details about it's mass, orbit, and general surface temperature, not much else can be said for certain about what the planet is actually like. The more important point of this planets discovery is what it could mean for the odds of finding other "Earth-Like" planets capable of sustaining life. Because the fact that a planet like this has been discovered in a system not only within our own galaxy but within 20 light years of our own solar system, is a good indication that habitable planets are in fact abundant throughout our galaxy.


You can read the original press release from The University of California: HERE. You should also check out Phil Plaits post on this subject as well which is the most detailed post I was able to find on the subject.
Monday, October 11th, 2010 - Astronomer Francesco Pepe of the Geneva Observatory and the Swiss group announced that they had been unable to find any reliable sign of a fifth planet in Gleise's habitable zone.


Go HERE for more info.

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