Scientists from the European Southern Observatory working in Chile have found a new planet outside our solar system that is more like Earth than any other known planet. Although the new planet is relatively close to us in astronomical terms -- less than 200 trillion (200,000,000,000,000) kilometers away -- astronomers need much more information before they can predict whether it harbors life.
Like Earth, the new planet "Gliese 581c" orbits its sun in "the habitable zone." The estimated surface temperature is between minus 3 and 40 degrees (celsius) -- neither too cold nor too hot for life as we know it. This means there could be liquid water on the planet's surface.
A team from the European Southern Observatory working at the ESO's La Silla Paranal site in Chile confirmed the planet's existence. St.phane Udry is a principal author of their scientific report:
"At the distance of the planet from the star, we expect water to be present on the surface of the planet. And when you speak about water, you may speak about life."
Finding this planet orbiting one of hundreds of billions of stars in our (Milky Way) galaxy was a great technological achievement, but nobody knows yet how far it advances the search for life outside Earth. American astrophysicist Steve Maran says of Gliese 581c:
"It's not quite the Earth yet. We don't know how a planet like that would differ from the Earth, but it's more like the Earth than any of the more than 200 other planets we've found so far."
The new planet, about 50 % larger in diameter than Earth, is in the constellation Libra. Its sun is a red dwarf star -- much smaller, dimmer and cooler than our sun. The planet is much closer to its sun than Earth is to ours, completing one orbit every 13 days.
"It's the smallest planet yet found, the one closest to being like our Earth. But it's still five times heavier and probably half again as big."
Computer models indicate Gliese 581c could have a rocky surface -- like Earth -- or that it might be covered with oceans. But could it support life? Many questions await answers. Astronomers are now looking much more closely at other similar (red dwarf) stars that could have planets with even more Earth-like conditions.