Bolometer, << boh LOM uh tuhr, >> is a device similar to a highly sensitive thermometer. It measures extremely small amounts of heat produced by certain types of radiant energy, chiefly infrared rays. Bolometers are so sensitive that they can detect infrared rays from the most distant galaxies in the universe.
A bolometer has a thin conducting strip that forms part of an electric circuit. The strip becomes slightly warmer when even a small amount of radiation touches it. This heating of the strip produces a change in the circuit’s conductivity (ability to carry current). The difference in conductivity shows the strength of the radiation. Some bolometers can operate at temperatures near absolute zero (-273.15 °C). The sensitivity of a bolometer increases tremendously at such extremely low temperatures. Samuel P. Langley, an American-born astronomer and physicist, invented the device in 1880.
