Comet’s 10 Million-Mile Tail Lights Up in Infrared
NASA’s new infrared telescope has released its first images.
The Wide-Field Infrared Survey Explorer has returned more than 250,000 raw images. To celebrate its performance thus far, NASA selected four of them for processing and publication.
Above, you can see the comet, Siding Spring, which was discovered in 2007 by Australian observers. Its 10 million-mile-long tail is made of glowing dust pushed away from its nucleus by the solar wind.
WISE launched on Dec. 14, 2009 and took in its first starlight at the end of the month. The telescope is intended to survey the entire sky looking for cosmic oddities. The mission will also provide better data on the average size of asteroids in the solar system, which will refine scientists’ estimates of how often a dangerous near-Earth object hits the Earth.
WISE is one of three space-based telescopes that observe in the infrared. NASA’s Spitzer Space Telescope and the Herschel Space Observatory also look at the longer wavelength side of the electromagnetic spectrum. Because the longer light waves travel more effectively through fine particles, the infrared is best for observing dusty regions.
In the image below, we see the Andromeda galaxy’s dusty spiral arms. WISE has four detectors in the infrared spectrum, which measure light with wavelengths of 3.4, 4.6, 12, and 22 microns. By using only the detectors that can measure the longest wavelengths, scientists can generate images like the one below, which shows just the dusty arms of the galaxy, which are heated by young stars.