SOURCE: BBC News
3 February 2009
The smallest planet yet found outside the Solar System has been detected by a French space telescope.
The rocky world is less than twice the size of Earth.
Only a handful of planets have so far been found with a mass comparable to Earth, Venus, Mars or Mercury.
The discovery was made by Corot, an orbiting observatory with a 27cm-diameter telescope to search for planets orbiting other stars.
About 330 of these "exoplanets" have been discovered so far. But most of them have been gas giants similar to Jupiter or Neptune.
"For the first time, we have unambiguously detected a planet that is 'rocky' in the same sense as our own Earth," said Malcolm Fridlund, Corot project scientist from the European Space Agency (Esa).
"We now have to understand this object further to put it into context, and continue our search for smaller, more Earth-like objects with Corot," he added.
The new find, Corot-Exo-7b, orbits its Sun-like star once every 20 hours. Although very close to Earth in terms of width, its mass is several times that of our own planet.
Because the planet is so close to its parent star, its temperature is between 1,000 and 1,500C - far too hot to support life.