Exoplanet Nearest Earth Not Habitable
Since man first looked up into the twinkling eyes of the night sky we, as a species, have been curious about heavenly bodies.
While we have since made great strides in dissecting and understanding aspects of the space made possible through advanced stellar technologies
But, the holy grail of our search has been the search for life; confirmation that we are not alone, or that we have found another planet that can support human life. We are, and have always been explorers. We have an insatiable need to know what is over the next hill, what is on the other side.
On April 21, 2009, a planet orbiting Gliese 581, Gliese 581 e, was announced with an approximate mass of 1.9 Earth masses.
Gliese 581 c initially generated interest because it was originally reported to be the first potentially Earth-like planet in the habitable zone of its star, with a temperature right for liquid water on its surface, and by extension, potentially capable of supporting some forms of Earth-like life.
However, further research on the potential effects of the planetary atmosphere casts doubt upon the habitability of Gliese 581 c and indicates that the (unconfirmed) fourth planet in the system, Gliese 581 g, is a better candidate for an atmosphere which may support life. The Gliese 581 system is relatively close to Earth, at 20.3 light years (192 trillion km or 119 trillion miles) in the direction of the constellation of Libra.
In a report in Nature, the European Southern Observatory's La Silla facility in Chile found a planet near Alpha Centauri B using the Harps instrument. The planet has at minimum the same mass as Earth, but circles its star far closer than Mercury orbits our Sun.
Harps and instruments like it measure the subtle change in color - the redshift or blueshift - of the host star's light as its orbit moves it slightly closer to and further away from Earth.