The near infrared can be detected as heat, as discovered by William Herschel in 1800. He found that thermometer, placed beyond the red end of a spectrum produced by a prism, showed a rise in temperature. Near infrared has many uses, for example diagnosis of breast cancer and aerial surveying. Mid or intermediate infrared is used for chemical research to investigate molecular binding energies. When the molecular vibration is equal to the infrared frequency, resonance occurs. This can be detected by absorption spectroscopy. Infrared is also used in image intensifiers.
Very little of the infrared spectrum from space reaches to sea-level, although more of it can be observed by high-altitude aircraft, such as the SOFIA (Stratospheric Observatory for Infrared Astronomy), or telescopes on high mountaintops (such as the peak of Mauna Loa in Hawaii). See also infrared astronomy.
Related categories HEAT AND THERMODYNAMICS
WAVES AND WAVE PHENOMENA
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