Info-Authority: Infrared

Infrared is a form of radiation consisting of invisible electromagnetic waves ranging from one millimeter to three-quarters of a millimeter in length. It is a medium-length wave on the electromagnetic spectrum: waves shorter than infrared lengths are known as microwaves, while waves longer than infrared are visible to the human eye and make up light. Light waves are emitted from objects that are extremely hot (e.g. sunlight, or flames) while infrared waves are emitted from essentially everything else -- any object that has mass and does not emit its own light, from things as cold as ice cubes to those as warm as heated charcoal, gives off some degree of infrared radiation. These infrared waves can be felt by the human body in the form of heat, but they cannot be seen without use of special technologies. In recent years, however, such technologies have become widely available, and have been discovered to possess a variety of practical applications.

Infrared Night Vision

Infrared waves are most commonly harnessed to allow individuals to see in low-light areas, particularly through the use of night vision goggles. Night vision goggles work by detecting infrared radiation and converting it into imagery visible to the human eye so that cooler objects appear in colors towards the blue spectrum and warmer objects appear in colors towards the red spectrum. This allows for easily distinguishing warm bodies from cool terrain. Night vision is especially useful for military and law-enforcement personnel, who frequently require snap thermal information in order to determine targets. It is also used by firefighters, who make use of infrared to comprehend their surroundings in smoke-filled environs. Night vision is not limited to humans: the technology behind such goggles is also found in the natural physiology of certain animals, most notably rattlesnakes, who are able to perceive in infrared through "pits" along their body which pick up sensory information. Such animals commonly use infrared to hunt in lightless warrens and to strike at warmer (and hence more vital) parts of the bodies of their prey.

Infrared Photography

Infrared is also of use in photography, which can be converted into thermal colors to give valuable information as to the varying degrees of heat in a particular scene. This can be especially useful in satellite photography; for example, in helping to determine the relative temperatures of layers of clouds, or the more active regions of an urban landscape. Such imaging is capable of extremely thorough detail. A picture of a person's skull in infrared will reveal a curious collage of red and orange around warmer regions of the face as well as blue and green around cooler areas; in the case of an animal, such as a cat or dog, the wet nose will be a vivid blue. Because of its surreal multi-hued appearance, infrared photography was particularly popular for use by musicians on album covers in the 1960s.

Infrared Data Transmitters

Another common use for infrared is the transmission of data, particularly by means of remote control. Such devices emit an infrared signal which is then transformed into an electrical current by a receiver on a television or other electronic device to which the remote is synchronized. Infrared is ideal for this purpose because it is invisible, cannot usually be felt by humans, and does not permeate walls, thus avoiding interference with other nearby machines.

By Matthew Ingalls




	Infrared Infrared is a form of radiation consisting of invisible electromagnetic waves ranging from one millimeter to three-quarters of a millimeter in length. It is a medium-length wave on the electromagnetic spectrum: waves shorter than infrared lengths are known as microwaves, while waves longer than infrared are visible to the human eye and make up light. Light waves are emitted from objects that are extremely hot (e.g. sunlight, or flames) while infrared waves are emitted from essentially everything else -- any object that has mass and does not emit its own light, from things as cold as ice cubes to those as warm as heated charcoal, gives off some degree of infrared radiation. These infrared waves can be felt by the human body in the form of heat, but they cannot be seen without use of special technologies. In recent years, however, such technologies have become widely available, and have been discovered to possess a variety of practical applications. Infrared Night Vision Infrared waves are most commonly harnessed to allow individuals to see in low-light areas, particularly through the use of night vision goggles. Night vision goggles work by detecting infrared radiation and converting it into imagery visible to the human eye so that cooler objects appear in colors towards the blue spectrum and warmer objects appear in colors towards the red spectrum. This allows for easily distinguishing warm bodies from cool terrain. Night vision is especially useful for military and law-enforcement personnel, who frequently require snap thermal information in order to determine targets. It is also used by firefighters, who make use of infrared to comprehend their surroundings in smoke-filled environs. Night vision is not limited to humans: the technology behind such goggles is also found in the natural physiology of certain animals, most notably rattlesnakes, who are able to perceive in infrared through "pits" along their body which pick up sensory information. Such animals commonly use infrared to hunt in lightless warrens and to strike at warmer (and hence more vital) parts of the bodies of their prey. Infrared Photography Infrared is also of use in photography, which can be converted into thermal colors to give valuable information as to the varying degrees of heat in a particular scene. This can be especially useful in satellite photography; for example, in helping to determine the relative temperatures of layers of clouds, or the more active regions of an urban landscape. Such imaging is capable of extremely thorough detail. A picture of a person's skull in infrared will reveal a curious collage of red and orange around warmer regions of the face as well as blue and green around cooler areas; in the case of an animal, such as a cat or dog, the wet nose will be a vivid blue. Because of its surreal multi-hued appearance, infrared photography was particularly popular for use by musicians on album covers in the 1960s. Infrared Data Transmitters Another common use for infrared is the transmission of data, particularly by means of remote control. Such devices emit an infrared signal which is then transformed into an electrical current by a receiver on a television or other electronic device to which the remote is synchronized. Infrared is ideal for this purpose because it is invisible, cannot usually be felt by humans, and does not permeate walls, thus avoiding interference with other nearby machines. By Matthew Ingalls Related Links: NASA - Infrared Waves Information on infrared from the NASA Web site.