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First Earth-Sized Planets Spotted in Remote Constellation

An artist's conception illustrates Kepler-20e. Image credit: NASA/Ames/JPL-Caltech

An artist's conception illustrates Kepler-20e. Image credit: NASA/Ames/JPL-Caltech

Astronomers working with NASA's orbiting Kepler space telescope have discovered a pair of Earth-sized planets far outside our solar system, the latest find for scientists searching for extraterrestrial life.

A joint statement by NASA headquarters and the Jet Propulsion Laboratory in ((the western U.S. state of)) California say the newly discovered planets, named Kepler 20e and Kepler 20f, have rocky surfaces, just like Earth. They also are orbiting around a parent star similar to our Sun.

But astronomers say the planets are orbiting so close to their star that the temperatures, calculated at 760 Celsius and 425 Celsius, make it impossible to nurture life as we know it.

One of the planets is just 3 percent bigger than Earth, while the other is 13 percent smaller. Astronomers say the two planets have three gas-giant siblings in the planetary system. All five planets are interspersed and orbit closer to their parent star than our solar system's innermost planet, Mercury.

Spotting the two planets is a technical feat for scientists. They are the smallest so-called "exoplanets" ever confirmed around a star like our Sun. The parent star, called Kepler 20, is about a thousand light years from Earth.

Earlier this month, Kepler astronomers announced the discovery of a super-Earth-sized planet orbiting another distant star with a life-friendly surface temperature of around 22 degrees Celsius.

Scientists say that planet, Kepler 22b, is believed to be 2.4 times the size of the Earth and circles the appropriate distance from its parent star for liquid water to possibly exist on its surface. That planet is located about 600 light years away.

NASA's Kepler telescope was launched in 2009 and is scanning a narrow segment of the cosmos, observing an estimated 150,000 stars.

Some information for this report was provided by AP, AFP and Reuters