New NASA Craft, With Infrared Power, Will Map the Unseen Sky
By Dennis Overbye
The New York Times
December 7, 2009
SEEING STARS The Wide‐field Infrared Survey Explorer, which contains a four‐million‐pixel camera, will photograph the entire sky every six months.
Most of the light from stars and other objects like planets in the universe is doubly invisible. It comes in the form of infrared, or heat radiation, with wavelengths too long for our eyes to pick up. Moreover, most infrared wavelengths do not penetrate the Earth’s atmosphere to get to our unseeing eyes.
So to take a proper inventory of cosmic shenanigans, astronomers have had to take to space. On Friday, they will get a little more help when the National Aeronautics and Space Administration is scheduled to launch the Wide‐field Infrared Survey Explorer, or WISE, into orbit from Vandenberg Air Force Base in California as early as 9:09 a.m., Eastern time.
Circling the Earth in a polar orbit 300 miles high, the spacecraft, equipped with a 16‐inch telescope and infrared detectors, will photograph the entire sky every six months.
WISE is a successor to the Infrared Astronomy Satellite, or IRAS, which was launched in 1983 and made the first heat maps of the sky. And it is a trailblazer for the giant James Webb Space Telescope due in 2014.
But whereas IRAS had 62 pixels in its camera, WISE has 4 million, said Edward L. Wright of the University of California, Los Angeles, principal investigator for the spacecraft. As a result, WISE will be hundreds of times as sensitive as its predecessor and able to survey a vastly larger volume of space.
Dr. Wright said he and his colleagues expected to see millions of new infrared sources, including ultraluminous galaxies that are breeding stars copiously inside shrouds of dust, and a thousand of the cool almost‐stars known as brown dwarfs, which are bigger than Jupiter but too small to ignite thermonuclear reactions.
“We should find out how many old, cold brown dwarfs are out there,” Dr. Wright said.
The other prime targets include asteroids, especially so‐called near‐Earth objects that might one day pose a threat to civilization. The WISE astronomers hope to measure the diameters of hundreds of thousands of asteroids to get a better sense of how dangerous they are.
Dr. Wright said the project had been almost 12 years in the making and cost $320 million, including operations and launching.
“What we hope to do is find the most interesting objects for next‐generation telescopes to look at,” he said.
“If we don’t find something totally unexpected,” he added, “I’ll be surprised.”
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