Mission
WISE surveyed the sky in four wavelengths of the infrared band, at a very high sensitivity. Its detector arrays have 5-sigma sensitivity limits of 120, 160, 650, and 2600 microjanskies (µJy) at 3.3, 4.7, 12, and 23 micrometres (aka microns). This is a factor of 1,000 times better sensitivity than the survey completed in 1983 by the IRAS satellite in the 12 and 23 micrometres (micron) bands, and a factor of 500,000 times better than the 1990s survey by the Cosmic Background Explorer (COBE) satellite at 3.3 and 4.7 micrometres. On the other hand, IRAS could also observe 60 and 100 micron wavelengths.
- Band 1 – 3.4 micrometres (microns) – broad-band sensitivity to stars and galaxies
- Band 2 – 4.6 micrometres – detect thermal radiation from the internal heat sources of sub-stellar objects like brown dwarfs
- Band 3 – 12 micrometres – detect thermal radiation from asteroids
- Band 4 – 22 micrometres – sensitivity to dust in star-forming regions (material with temperatures of 70–100 kelvins)
The primary mission lasts ten months: one month for checkout, six months for a full-sky survey, then an additional three months of survey until cryogenic coolant runs out. The partial second survey pass will facilitate the study of changes (e.g. orbital movement) in observed objects.
Read more about this topic: Wide-field Infrared Survey Explorer
Famous quotes containing the word mission:
“I cannot be a materialist—but Oh, how is it possible that a God who speaks to all hearts can let Belgravia go laughing to a vicious luxury, and Whitechapel cursing to a filthy debauchery—such suffering, such dreadful suffering—and shall the short years of Christ’s mission atone for it all?”
—D.H. (David Herbert)
“We can come up with a working definition of life, which is what we did for the Viking mission to Mars. We said we could think in terms of a large molecule made up of carbon compounds that can replicate, or make copies of itself, and metabolize food and energy. So that’s the thought: macrocolecule, metabolism, replication.”
—Cyril Ponnamperuma (b. 1923)
“... [a] girl one day flared out and told the principal “the only mission opening before a girl in his school was to marry one of those candidates [for the ministry].” He said he didn’t know but it was. And when at last that same girl announced her desire and intention to go to college it was received with about the same incredulity and dismay as if a brass button on one of those candidate’s coats had propounded a new method for squaring the circle or trisecting the arc.”
—Anna Julia Cooper (1859–1964)