Kepler II

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Most of the telescopes that have been launched into space have been designed to look all around the sky, allowing them to study just about any region of the universe.

But as mission scientist Alan Boss explains, a soon-to-be-launched telescope called Kepler will do something a little different:

BOSS: It is a roughly 1-meter-diameter telescope which will be staring at a hundred thousand stars in the constellations Cygnus and Lyra, easily visible from the northern hemisphere. It will stare at those hundred thousand stars for about three and a half years continuously, without ever closing its eyes -- no blinking allowed.

The goal of that stare-down is to find planets orbiting the stars -- especially Earth-like planets around Sun-like stars.

In particular, Kepler will look for events called transits, in which a planet briefly passes in front of its parent star, blocking a little bit of the star's light.

Kepler will accomplish this with an array of 42 CCDs -- the same type of detectors found in digital cameras. But the CCDs on Kepler are so sensitive that they should be able to detect a drop in a star's light of just one one-hundredth of a percent.

If it's repeated a few times, this tiny flicker in a star's brightness will do much more than just tell us that the star has a planet. It'll reveal the planet's size, its distance from the star, and its temperature. And the total number of discoveries will tell us if Earth-like planets are common -- or if our comfortable little world is a cosmic rarity.

Script by Damond Benningfield, Copyright 2009

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