Infrared radiation is used in infrared saunas to heat the occupants, and to remove ice from the wings of aircraft (de-icing). It is also gaining popularity as a method of heating asphalt pavements in place during new construction or in repair of damaged asphalt. Infrared can be used in cooking and heating food as it heats only opaque, absorbent objects and not the air around them, if there are no particles in it.
The infrared portion of the spectrum has a number of technological uses, including target acquisition and tracking by the military; remote temperature sensing; short-ranged wireless communication; spectroscopy, and weather forecasting. Telescopes equipped with infrared sensors are used in infrared astronomy to penetrate dusty regions of space, such as molecular clouds; detect low temperature objects such as planets orbiting distant stars, and to view highly red-shifted objects from the early history of the universe.
At the atomic level, infrared energy elicits vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states. Infrared spectroscopy is the examination of absorption and transmission of photons in the infrared energy range, based on their frequency and intensity.[3]
"Heat"
Infrared radiation is popularly known as "heat" or sometimes "heat radiation," since many people attribute all radiant heating to infrared light, but this is a widespread misconception. Light and electromagnetic waves of any frequency will heat surfaces which absorb them. Infrared light from the sun only accounts for 50% of the heating of the Earth, the rest being caused by visible light.[citation needed] Green (or even ultraviolet) lasers can char paper and incandescently-hot objects will put out visible radiation. However, it is true that objects at room temperature will emit radiation mostly concentrated in the 8-12 micron band (see black body and Wien's displacement law).Unlike heat transmitted by thermal conduction or thermal convection, radiation can propagate through a vacuum. Heat is the energy in transient form and flows due to temperature difference.
