Science terms or definitions are necessary, but knowing a definition and understanding a subject are sometimes not the same. With that disclaimer, I’ll offer this definition of the electromagnetic spectrum (EMS). The electromagnetic spectrum is the complete range of possible wavelengths of electromagnetism, from longest to shortest.
Imagine the length of a long piece of string to represent the distance between electromagnetic waves. We could cut the string in any fractional length we choose, and continue to divide the string into smaller and smaller pieces. In theory, there is no limit to how short the pieces of string could be cut or how many pieces we could cut. It’s also possible to make longer and longer pieces of string by tying on additional pieces. Down the road we wind up with an infinitely large number of string pieces of many different lengths. Likewise, possible wavelengths of electromagnetism are virtually infinite.
Electromagnetic waves include radio, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. These range in length from many kilometers to only trillionths of a centimeter. In the following brief primer on electromagnetic waves, we will use radio waves as an illustration. The length of waves in the radio band of the EMS varies over a wide range.
All electromagnetic waves are described in terms of packages of electromagnetic energy (photons) traveling at 300,000 km/sec. They are described according to wave length--the distance between the waves. In addition, they are described according to frequency--hertz (symbol Hz)--the number of waves passing a given point per second. All AM radio stations broadcast on the “medium wave” band of the radio portion of the EMS. At the 300,000 km/sec speed, an AM radio station at 600 on the dial sends out 600,000 waves, or photons, per second. It is said, therefore, to have a frequency of 600 kHz (600,000 Hz). Your radio receiver detects them and converts the information in the waves to audible, intelligible sound. Wavelengths of the 600 kHz AM station--the distance between one wave and the next--are about one-half kilometer.
My personal fondness for investigating the EMS may more aptly be described as astonished fascination. In lighter moments I have stated that when this created order ends and the New Creation begins (Revelation 3:12; Revelation 21), I would like to discover, directly from the Creator of this present order, more mysteries of the EMS I did not understand. Included in the questions would be why different waves have such a markedly different effect on man, our equipment, and our environment, when the only physical difference between them is a difference in wavelength. In many cases, that difference is unimaginably small.
The only electromagnetic wave mentioned specifically in the Bible is light, a topic for another post. The scientific knowledge of our day enriches our appreciation of scripture’s spiritual imagery concerning light.