ESA; (inset) Medialab

ScienceShot: Billion-Pixel Array Will Map the Milky Way

Technicians have assembled the largest digital camera ever built for a space mission. Completed last month, the so-called billion-pixel array (shown during assembly) is made up of 106 charge-coupled imaging devices, each slightly smaller than a credit card and thinner than a human hair. Part of the European Space Agency's Gaia probe, the camera is due to ride into space in 2013, the agency reported yesterday. During the 5-year mission, Gaia's instruments will repeatedly measure the position, color, intensity, and spectra of stars and other objects as dim as magnitude 20, about 400,000 times fainter than can be seen with the naked eye. The resulting 3D star map will include more than 1 billion stars in our galaxy and in nearby star clusters and should provide unprecedented insights into the composition, formation, and evolution of the Milky Way. Besides discovering thousands of distant, dim objects such as brown dwarfs, Gaia's sensors will likely detect hundreds of thousands of comets, asteroids, and other minor bodies in our solar system, the researchers say.

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