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NARRATOR: NASA's Kepler mission has confirmed the discovery

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of the first Earth-size planets outside our solar system

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orbiting a sun-like star.

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Located about 1,000 light years from Earth, the Kepler-20 solar system

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has five planets orbiting a star similar to the Sun.

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Kepler-20f, the 4th planet in the system,

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orbits its star every 19.6 days

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and has a surface temperature of 800 degrees Fahrenheit.

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Kepler-20e has an orbital period of 6.1 days

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and has a surface temperature of 14-hundred degrees Fahrenheit.

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It is about 90 percent the size of Earth.

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Kepler-20f is slightly larger than Earth,

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with a radius that is 3 percent larger.

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The extreme temperatures and proximity to their host star

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means that the planets are not in the habitable zone,

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the region where liquid water could exist on the surface.

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These discoveries are a validation of the complex data analysis process

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that the Kepler team is using to detect transits

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of Earth-sized planets in front of their stars.

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Scientists hope to eventually find Earth-size, habitable planets

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with liquid water that could sustain life as we know it.

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Kepler is on a three-and-a-half year mission

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to search for Earth-size planets in our galaxy.