The sun is the source of all life on Earth. The sun's rays that reach the surface of the planet consist of ultraviolet light (UV), visible light and infrared radiation (IR). It is this infrared radiation that is responsible for the transport of heat from the sun.
Infrared has a number of special properties. The amount of heat that infrared radiation loses travelling through air is negligible. Only once the infrared radiation comes into contact with an object does it release heat. This is why the weather is warmer on cloudless days. In addition to this, the so-called long-wave infrared radiation has a penetrating effect; this enables it to be absorbed by the human body (muscles and tissues).
Everything that lives, grows and flourishes needs infrared radiation and emits infrared radiation. This is why we can track down people and animals in the dark using special infrared night vision devices. The penetrating properties of infrared radiation warm the body and have a biological, thermic and therapeutic effect. The body responds to the infrared radiation by increasing its blood circulation and perspiration rate. The body relaxes, secretes toxins, builds up its resistance and is reenergised.
The history of infrared
In 1880 William Herschel found that in a certain part of the light spectrum there was a connection between light and temperature, and so discovered what we know today as infrared. A great deal has happened since his discovery, and infrared is used in a wide range of applications. Infrared has been found to have a beneficial effect on the human body. The infrared radiation is absorbed by the skin and the underlying muscles and tissues and has a biological, thermic and therapeutic effect.