Background and Technology
Early Infrared Astronomy
After Sir William Herschel's discovery of infrared ,which showed that the Sun emits infrared radiation, astronomers tried to see if other objects in the universe gave out infrared waves. In 1856, astronomers used thermocouples (devices which convert heat into electric current) to detect infrared radiation from the Moon. Much later, in 1948 (decades before the first Moon landing), more sophisticated infrared studies of the Moon would show that its surface was covered with a fine powder. In the early 1900's, infrared radiation was successfully detected from the planets Jupiter and Saturn and from some bright stars such as Vega and Arcturus. However, the insensitivity of the early infrared instruments prevented the detection of other near-infrared sources. Work in infrared astronomy remained at a low level until breakthroughs in the development of new, sensitive infrared detectors were achieved in the 1960's.