A team of scientists discovered a planet in the Gliese 581 system that appears to be potentially habitable! This planet Gliese 581 g is part of a large multi-planet star system less than 21 light-years away. Courtesy of the press release:
The planet is tidally locked to the star, meaning that one side is always facing the star and basking in perpetual daylight, while the side facing away from the star is in perpetual darkness. One effect of this is to stabilize the planet’s surface climates, according to Vogt. The most habitable zone on the planet’s surface would be the line between shadow and light (known as the “terminator”), with surface temperatures decreasing toward the dark side and increasing toward the light side.
“Any emerging life forms would have a wide range of stable climates to choose from and to evolve around, depending on their longitude,” Vogt said.
The researchers estimate that the average surface temperature of the planet is between -24 and 10 degrees Fahrenheit (-31 to -12 degrees Celsius). Actual temperatures would range from blazing hot on the side facing the star to freezing cold on the dark side.
If Gliese 581g has a rocky composition similar to the Earth’s, its diameter would be about 1.2 to 1.4 times that of the Earth. The surface gravity would be about the same or slightly higher than Earth’s, so that a person could easily walk upright on the planet, Vogt said.
It’s like a science fiction story! And our prediction for discovering such a planet by May 2011 appears to be accurate, and even a bit conservative. The next step is to examine the planet’s atmosphere for the presence of oxygen.
What an exciting time to be alive.