Comet Gets WISE Treatment
Comet Siding Spring and its ghostly tail streak across the sky in one of the first infrared pictures taken by NASA's new Wide-field Infrared Survey Explorer (WISE) space telescope, which were released February 17.
The telescope, which launched in December 2009, will scour the sky for objects that give off infrared light.
"What we're able to see that's different with WISE is the cool dust being blown off the comet by the sun," said the WISE telescope's deputy project scientist Amy Mainzer.
Cold objects emit more energy at long infrared wavelengths than warm objects do, so WISE is particularly sensitive to icy comets and cool, rocky asteroids, she added. (See comet and asteroid pictures.)
"We can learn a great deal about the physical properties of comets, such as their size and how big their dust particles are," Mainzer said.
The last time the entire sky was mapped in infrared light was in 1983, using the Infrared Astronomical Satellite, or IRAS, which had a 62-pixel sensor. WISE uses a four-million pixel—or four-megapixel—sensor.
"I would say it's the difference between an old-fashioned landline phone and an iPhone," Manzier said.