History of the telescope of the IRAS satellite in 1983 revolutionized infrared astronomy from space. This reflecting telescope which had a mirror, operated for nine months until its supply of coolant (liquid helium) ran out. It surveyed the entire sky detecting 245,000 infrared sources—more than 100 times the number previously known. Although optical telescopes can image the near ultraviolet, the ozone layer in the stratosphere absorbs ultraviolet radiation shorter than 300 nm so most ultra-violet astronomy is conducted with satellites. Ultraviolet telescopes resemble optical telescopes, but conventional aluminium-coated mirrors cannot be used and alternative coatings such as magnesium fluoride or lithium fluoride are used
Why Does the Sun Shine? (The Sun Is a Mass of Incandescent Gas) Why Does the Sun Shine? (The Sun Is a Mass of Incandescent Gas) Why Does the Sun Shine? (The Sun Is a Mass of Incandescent Gas) is an EP by alternative rock band They Might Be Giants, released in 1993. The EP is notable for being their first release with a full-band lineup, rather than only the two original members (John Flansburgh and John Linnell) performing. It was also released as a single on 7" vinyl. All of the songs on the EP are cover versions, except for one. The title song is a cover of a song by Hy