A light trail made by a headlamp.
(Photo by Josh Horak, Solid Rock Outdoor Ministries)
True Light:
Beyond Waves, Particles, Rods, and Cones
By Jim Doenges
Monthly Series: January 2007
With the very first creative words God spoke, He said “Let there be light,” and there was light. God saw that the light was good, and He separated the light from the darkness (Genesis 1:3-4). Throughout the Old Testament, light is used to refer to God’s presence, His salvation, or His revelation:
- “You are my lamp, O Lord; the Lord turns my darkness into light” (2 Samuel 22:29).
- “The Lord is my light and my salvation — whom shall I fear?” (Psalm 27:1).
- “For with you is the fountain of life; in your light we see light” (Psalm 36:9).
- “For you have delivered me from death and my feet from stumbling, that I may walk before God in the light of life” (Psalm 56:13).
- “Even in the darkness light dawns for the upright, for the gracious and compassionate and righteous man” (Psalm 112:4).
- “For these commands are a lamp, this teaching is a light” (Proverbs 6:23)
- “Come, O house of Jacob, let us walk in the light of the Lord” (Isaiah 2:5).
- “Arise, shine, for your light has come, and the glory of the Lord rises upon you. See, darkness covers the earth and thick darkness is over the peoples, but the Lord rises upon you and His glory appears over you. Nations will come to the light, and kings to the brightness of your dawn” (Isaiah 60:1-3).
- “Though I sit in darkness, the Lord shall be my light” (Micah 7:8)
Light is defined by the American Heritage Dictionary as “electromagnetic radiation that has a wavelength in the range from about 3,900 to about 7,700 angstroms and that may be perceived by the unaided, normal human eye.” Light — as radiant energy that is part of creation - has been the subject of conjecture, study, and experiment by physicists and other scientists for centuries. What is light? This was debated for a long time. Many scientists made contributions to our knowledge about light, including Isaac Newton, Max Planck, Christian Huygens, Thomas Young, Albert Einstein, Louis de Broglie, and others.
Light can behave like a stream of high-speed particles, which helps explain things like X-rays, radiation, and photoelectricity. But light can also appear to behave like waves in motion. This helps explain things like reflection and refraction.
The speed of light through air is about 186,000 miles per second. Light slows down when it travels through denser mediums and the speed can be different for each color of light. Refraction is the deflection of a wave as it passes through a medium of nonuniform density. Refraction of light is demonstrated by rainbows, those symbols from God of His covenant promise with all the living creatures that He will never again destroy the world with a flood (see Genesis 9:8-16). When sunlight passes through drops of rain or mist suspended or falling through less dense air it is separated into its spectral colors. Rainbows can catch our eyes and amaze us. They should always remind us of God.
Within God’s animal kingdom, He created varying kinds of photoreceptors — organs that are sensitive to light. These range in complexity from simple light-sensitive cells on the body surface of some small invertebrates to the exquisitely complex eyes of vertebrates. Many arthropods have compound eyes that are made of a collection of many independent visual units. The eye of a honeybee contains about 15,000 of these units. Compound eyes probably do not produce very distinct images but they are very good at detecting motion.
Traditional film cameras were modeled after the vertebrate eye. The amount of light allowed in to the eye is controlled by varying the diameter of the entrance hole. Eyes like ours contain a light-tight chamber with a lens system in front that focuses an image of the visual field on a light-sensitive surface in back (the retina). The retina has two different kinds of photoreceptors: rods and cones. Rods are involved with colorless vision in dim light; the human eye has about 125 million rods. Cones are involved in color vision in ample light, and we have about 7 million of these in each eye. The region of keenest vision — the fovea centralis — is in the center of the retina. The fovea only contains cones and the amount determines an animal’s visual acuity. The human fovea has about 150,000 cones per square millimeter but the fovea of many birds have up to 1 million. We would have to use 8-power binoculars to see as well. Chemical reactions occur when light strikes light-sensitive pigments in rods and cones, causing nerve impulses that travel to the brain. The processing of images occurs in the optic areas of the cerebral cortex. We see with our brains, not our eyes.
Cones require 50 to 100 times more light to stimulate their light-sensitive pigment than do rods. Therefore night vision is almost totally rod vision. That’s why landscapes illuminated by moonlight appear in only shades of gray, white, and black. God created some creatures to be strictly nocturnal; animals like bats and owls have retinas composed almost entirely of rods. Surprisingly, most mammals are color blind while most birds and bony fishes have good color vision.
Additional definitions of light in the dictionary are “spiritual or intellectual comprehension or awareness, a person who inspires, a prominent or distinguished person — especially one serving as an example for others, and to be born or come into existence.” Ah, now we are shedding new and deeper light on the subject.
Jesus provides an entirely new understanding and meaning to “light.” Just as the pillar of fire was a visible symbol of God’s presence for the people of Israel (see Exodus 13:21), so Jesus is the very light of life for every believer. Just as God often spoke to His people from the pillar of fire, so Jesus speaks to us today and tomorrow as The Light.
Matthew explains in his Gospel that after Jesus’ experience in the wilderness, He taught His climbing companions (the disciples) up on a mountainside. Jesus said to them: “You are the light of the world. A city on a hill cannot be hidden. Neither do people light a lamp and put it under a bowl. Instead they put it on its stand, and it gives light to everyone in the house. In the same way, let your light shine before men, that they may see your good deeds and praise your Father in heaven” (Matthew 5:14-16).
In the Gospel of John, light becomes a synonym for salvation and the Lord Himself. Verse 3 of the first chapter states: “Through Him all things were made; without Him nothing was made that has been made.” God made everything — including waves and particles, rods and cones, and everything we behold with our eyes. Echoing the Old Testament, verse 4 states: “In Him was life, and the life was the light of men. The light shines in the darkness, but the darkness has not understood it.”
In John’s Gospel, Jesus states:
- “This is the verdict: Light has come into the world, but men loved darkness instead of light because their deeds were evil. Everyone who does evil hates the light, and will not come into the light for fear that his deeds will be exposed. But whoever lives by the truth comes into the light, so that it may be seen plainly that what he has done has been done through God” (3:19-21).
- “I am the light of the world. Whoever follows me will never walk in darkness, but will have the light of life” (8:12).
- “While I am in the world, I am the light of the world” (9:5).
- “I have come into the world as a light, so that no one who believes in me should stay in darkness” (12:46).
John wrote further about walking in the Light in his first letter. “This, in essence, is the message we heard from Christ and are passing on to you: God is light, pure light; there is not a trace of darkness in Him. If we claim that we experience a shared life with Him and continue to stumble around in the dark, we’re obviously lying through our teeth — we’re not living what we claim. But if we walk in the light, God himself being the light, we also experience ea shared life with one another, as the sacrificed blood of Jesus, God’s Son, purges all our sin” (1 John 1:5-6, The Message). “The darkness in our lives disappears and the new light of life in Christ shines in” (1 John 2:8, Living Bible).
The light of God also shines in the heart of the Apostle Paul, as exemplified in his writings. In his second letter to the believers in Corinth, Paul alludes to Genesis as he teaches, “Remember, our Message is not about ourselves; we’re proclaiming Jesus Christ, the Master. All we are is messengers, errand runners from Jesus to you. It started when God said, 'Light up the darkness!' and our lives filled up with light as we saw and understood God in the face of Christ, all bright and beautiful” (2 Corinthians 4:5, The Message). Paul also exhorted the Christians in Ephesus: “The bright light of Christ makes your way plain. So no more stumbling around. Get on with it! … figure out what will please Christ, and then do it” (Ephesians 5:8, The Message).
James, the brother of Jesus wrote: “So, my dear friends, don’t get thrown off course. Every desirable and beneficial gift comes out of heaven. The gifts are rivers of light cascading down from the Father of Light. There is nothing deceitful in God, nothing two-faced, nothing fickle. He brought us to life using the true Word, showing us off as the crown of all His creatures” (James 1:16, The Message).
Just as a dark night sky is needed in order to see the brilliance of the stars, the darkest times in our lives are occasions when His Light can shine the brightest.
As it was foretold by the prophet Isaiah, in the future the light of the sun – those waves and particles — will not be needed for us to see. We will see by the light of the Son in the New Jerusalem of the restored earth after Christ’s return. “For the glory of God will give it light, and the nations of the earth will walk by this light, and there will be no night there” (see Revelation 21:23-25).
Climb on, in the Light.
Jim Doenges is the Director of Summit Stewards for Climbing For Christ.
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