Editing Infrared astronomy (section)

==History==
[[File:NICMOS cross cut.png|thumb|Hubble's ground-breaking near-infrared NICMOS]]
[[File:SOFIA with open telescope doors.jpg|thumb|right|200px|[[SOFIA]] is an infrared telescope in an aircraft, shown here in a 2009 test]]
The discovery of infrared radiation is attributed to William Herschel, who performed an experiment in 1800 where he placed a thermometer in sunlight of different colors after it passed through a [[prism (optics)|prism]].<ref name="caltech_herschel" /> He noticed that the temperature increase induced by sunlight was highest ''outside'' the visible spectrum, just beyond the red color. That the temperature increase was highest at infrared wavelengths was due to the spectral response of the prism rather than properties of the Sun, but the fact that there was any temperature increase at all prompted Herschel to deduce that there was invisible radiation from the Sun. He dubbed this radiation "calorific rays", and went on to show that it could be reflected, transmitted, and absorbed just like visible light.<ref name="caltech_herschel">{{cite web|url=http://coolcosmos.ipac.caltech.edu/cosmic_classroom/classroom_activities/herschel_bio.html |title=Herschel Discovers Infrared Light |access-date=9 April 2010 |publisher=Cool Cosmos |url-status=dead |archive-url=https://web.archive.org/web/20120225094516/http://coolcosmos.ipac.caltech.edu/cosmic_classroom/classroom_activities/herschel_bio.html |archive-date=25 February 2012  }}</ref>

[[File:Wrapped Up for the Cool Cosmos.jpg|thumb|left|High on the Chajnantor Plateau, the [[Atacama Large Millimeter Array]] provides an extraordinary place for infrared astronomy.<ref>{{cite news|title=First Results from the ESO Ultra HD Expedition|url=http://www.eso.org/public/announcements/ann14035/|access-date=10 May 2014|newspaper=ESO Announcement}}</ref>]]

Efforts were made starting in the 1830s and continuing through the 19th century to detect infrared radiation from other astronomical sources. Radiation from the Moon was first detected in 1856 by [[Charles Piazzi Smyth]], the Astronomer Royal for Scotland, during an expedition to Tenerife to test his ideas about mountain top astronomy. [[Ernest Fox Nichols]] used a modified [[Crookes radiometer]] in an attempt to detect infrared radiation from [[Arcturus]] and [[Vega]], but Nichols deemed the results inconclusive. Even so, the ratio of flux he reported for the two [[star]]s is consistent with the modern value, so [[George Rieke]] gives Nichols credit for the first detection of a star other than our own in the infrared.<ref name="rieke">{{cite journal | author = Rieke, George H. | title = History of infrared telescopes and astronomy | journal = Experimental Astronomy | volume = 25 | issue = 1–3 | pages = 125–141 | date = 2009 | doi = 10.1007/s10686-009-9148-7 | bibcode = 2009ExA....25..125R| s2cid = 121996857 }}</ref>

The field of infrared astronomy continued to develop slowly in the early 20th century, as [[Seth Barnes Nicholson]] and [[Edison Pettit]] developed [[thermopile]] detectors capable of accurate infrared [[photometry (astronomy)|photometry]] and sensitive to a few hundreds of stars. The field was mostly neglected by traditional astronomers until the 1960s, with most scientists who practiced infrared astronomy having actually been trained [[physicist]]s. The success of radio astronomy during the 1950s and 1960s, combined with the improvement of [[infrared detector]] technology, prompted more astronomers to take notice, and infrared astronomy became well established as a subfield of astronomy.<ref name="rieke"/><ref>{{cite book |last=Glass |first=Ian S. |date=1999 |title=Handbook of Infrared Astronomy |publisher=[[Cambridge University Press]]|location=Cambridge, England |isbn=0-521-63311-7}}</ref>

Infrared [[space telescope]]s entered service. [[United States Air Force Infrared Sky Surveys|Early infrared sky surveys]] were carried out by the United States Air Force using [[sounding rocket]]s.<ref name="Price2008"/> In 1983, [[IRAS]] made an all-sky survey. In 1995, the European Space Agency created the [[Infrared Space Observatory]]. Before this satellite ran out of [[liquid helium]] in 1998, it discovered protostars and water in our universe (even on Saturn and Uranus).<ref>{{Cite web|url=http://link.galegroup.com/apps/doc/CV2644300557/SCIC?u=mcc_pv&xid=d1c570e6|title=Science in Context - Document|website=link.galegroup.com|language=en|access-date=25 September 2017}}</ref>

On 25 August 2003, NASA launched the [[Spitzer Space Telescope]], previously known as the Space Infrared Telescope Facility.  In 2009, the telescope ran out of liquid helium and lost the ability to see [[far infrared]].  It had discovered stars, the [[Double Helix Nebula]], and light from [[extrasolar planet]]s.  It continued working in 3.6 and 4.5 micrometer bands.  Since then, other infrared telescopes helped find new stars that are forming, nebulae, and stellar nurseries. Infrared telescopes have opened up a whole new part of the galaxy for us. They are also useful for observing extremely distant things, like [[quasar]]s. Quasars move away from Earth. The resulting large redshift make them difficult targets with an optical telescope. Infrared telescopes give much more information about them.

During May 2008, a group of international infrared astronomers proved that [[intergalactic dust]] greatly dims the light of distant galaxies. In actuality, galaxies are almost twice as bright as they look. The dust absorbs much of the visible light and re-emits it as infrared light.