Pure Light and True Light

"The true light, which enlightens everyone..."

What is pure light?  Or maybe the first question ought to be, what is light?  Light is simply an electric-magnetic wave just like the waves of radio, TV, and x-rays except its wavelength is in the visible range.  The wavelength of FM radio and the TV channels 2 through 13 (at least before the switch to digital TV) is in the range of 3 feet to 18 feet.

The wavelength for light is in the range of 15 to 30 millionths of an inch, very small indeed.  X-rays have wavelengths that are much smaller still.  Our human eyes can only detect the waves in the visible range.  Our skin can detect the warmth of infra-red light (wavelengths longer than visible light) and can burn from ultra-violet light (wavelengths shorter than the visible ones).

What is pure light?  The definition I have in mind is light that has only one wavelength.  Most light that we see is made up of many different wavelengths.  Sun light is a continuous mixture from the deepest blues to the brightest reds and all colors in between as a prism or a rainbow can show.

But a laser, for example, produces a very narrow range of wavelengths, or a single wavelength as far as our discussion is concerned. And like a pod (school) of dolphins swimming along in synchronization, all the waves produced by the laser are in lock-step with each other which keeps the light from spreading out very much.  It is very useful light for medical and scientific uses because it can be focused so well.

What about true light?  More of the quote above is: In him was life, and the life was the light of men.  The light shines in the darkness, and the darkness has not overcome it... The true light, which enlightens everyone, was coming into the world (John 1:4-10 ESV).

Pure laser light is used in Lasik surgery, for example, to reshape the cornea of the eye to correct vision problems.  And there are types of lasers used to remove unwanted tattoos.

Another use of pure light is to measure accurately the distance to the moon within one inch.  This light is bounced back by reflectors left there in the late 1960’s and 1970’s at certain locations on the moon.

So just as pure light can be used in surgery to heal problems, and in astronomy to add accuracy to our measurements, the true light can be used to shine in the darkness of our world to reveal things that need revealing and to bring healing to our souls.