What is Infrared?
Our eyes are detectors which are designed to detect visible light waves (or visible radiation). Visible light is one of the few types of radiation that can penetrate our atmosphere and be detected on the Earth’s surface. As we have seen from the section on the discovery of infrared, there are forms of light (or radiation) which we cannot see. Actually we can only see a very small part of the entire range of radiation called the electromagnetic spectrum.
The electromagnetic spectrum includes gamma rays, X-rays, ultraviolet, visible, infrared, microwaves, and radio waves. The only difference between these different types of radiation is their wavelength or frequency. Wavelength increases and frequency (as well as energy and temperature) decreases from gamma rays to radio waves. All of these forms of radiation travel at the speed of light (186,000 miles or 300,000,000 meters per second in a vacuum). In addition to visible light, radio, some infrared and a very small amount of ultraviolet radiation also reaches the Earth’s surface from space. Fortunately for us, our atmosphere blocks out the rest, much of which is very hazardous, if not deadly, for life on Earth.
Infrared radiation lies between the visible and microwave portions of the electromagnetic spectrum. Infrared waves have wavelengths longer than visible and shorter than microwaves, and have frequencies which are lower than visible and higher than microwaves. Infrared is broken into three categories: near, mid and far-infrared. Near-infrared refers to the part of the infrared spectrum that is closest to visible light and far-infrared refers to the part that is closer to the microwave region. Mid-infrared is the region between these two.
Courtesy of Inframetrics
The primary source of infrared radiation is heat or thermal radiation. This is the radiation produced by the motion of atoms and molecules in an object. The higher the temperature, the more the atoms and molecules move and the more infrared radiation they produce. Any object which has a temperature i.e. anything above absolute zero (-459.67 degrees Fahrenheit or -273.15 degrees Celsius or 0 degrees Kelvin), radiates in the infrared. Absolute zero is the temperature at which all atomic and molecular motion ceases. Even objects that we think of as being very cold, such as an ice cube, emit infrared. When an object is not quite hot enough to radiate visible light, it will emit most of its energy in the infrared. For example, hot charcoal may not give off light but it does emit infrared radiation which we feel as heat. The warmer the object, the more infrared radiation it emits. The infrared image of a landing space shuttle (left) shows the how the tiles underneath the shuttle have been heated during re-entry.
Courtesy of Meditherm
Humans, at normal body temperature, radiate most strongly in the infrared, at a wavelength of about 10 microns (A micron is the term commonly used in astronomy for a micrometer or one millionth of a meter). In the image to the left,the red areas are the warmest,
followed by yellow, green and blue (coolest). The image to the right shows a cat in the infrared. The yellow-white areas are the warmest and the purple areas are the coldest. This image gives us a different view of a familiar animal as well as information that we could not get from a visible light picture. Notice the cold nose and the heat from the cat’s eyes, mouth and ears.
Some animals can “see” in the infrared. For example, snakes in the pit viper family (e.g. rattlesnakes) have sensory “pits,” which are used to detect infrared light. This allows the snake to find warm-blooded animals (even in dark burrows), by detecting the infrared heat that they radiate. Snakes with 2 sensory pits are thought to have some depth perception in the infrared. We experience infrared radiation every day. The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared. Although our eyes cannot see it, the nerves in our skin can feel it as heat. The temperature-sensitive nerve endings in your skin can detect the difference between your inside body temperature and your outside skin temperature. We also commonly use infrared rays when we operate a television remote.
Near, Mid, & Far Infrared
Infrared is usually divided into 3 spectral regions: near, mid and far-infrared. The boundaries between the near, mid and far-infrared regions are not agreed upon and can vary. The main factor that determines which wavelengths are included in each of these three infrared regions is the type of detector technology used for gathering infrared light.
Near-infrared observations have been made from ground based observatories since the 1960’s. They are done in much the same way as visible light observations for wavelengths less than 1 micron, but require special infrared detectors beyond 1 micron. Mid and far-infrared observations can only be made by observatories which can observe above the atmosphere. These observations require the use of special cooled detectors containing crystals like germanium whose electrical resistance is very sensitive to heat.
What the Researchers say about FIR
Far Infrared energy is not only safe, but highly beneficial for our bodies. Far Infrared lamps are actively used for medical treatments by doctors, chiropractors, acupuncturists, physical therapists, and massage therapists for arthritis, joints pain, stiff muscles, injuries to tendons and ligaments to promote a faster self body healing effect.
Infrared heat is “radiant” heat. Radiant heat is simply a form of energy that heats objects directly through a process called conversion, without having to heat the air in between.
Radiant heat is also called Infrared Energy. The infrared segment of the electromagnetic spectrum cannot be seen, but can be perceived as heat. Our sun produces most of its energy output in the infrared segment of the spectrum. Our atmosphere has a “window” in it that allows infrared engergy rays in the 7 ~ 14 micron range to safely reach the earth’s surface. When warmed, the earth radiates infrared rays in the 7 ~ 14 micron band with its peak output at 10 microns.
According to Dr. Tsu-Tsair Oliver Chi, in his summation on the mechanism of actions of infrared devices tuned to the human body; tissues needing a boost in their output selectively absorb these rays. The internal production of the infrared energy that normally occurs within our tissues is associated with a variety of healing responses and may require a boost to a maximal level to insure the fullest healing response possible in a tissue, which is being repaired. After boosting a tissue’s level to its maximum, the remaining rays pass onward harmlessly. This phenomenon is called “resonant absorption.”
Regular use of a sauna may be as effective as a means of cardiovascular conditioning and burning of calories as regular exercise.