The Light of Day

Part 1

by Greg Leitschuh

 "To go further into the mystery of light, we should note another phenomenon: light not only vibrates at different frequencies, it also can travel at different speeds and through different substances!"

Every day we see things with our eyes, from our first waking moment to bedtime at night. We look at everything around us using light. We appreciate many visual things from fine paintings and works of art to incredible special effects at the movies or on TV. All of us have been awestruck at dazzling sunsets, blue skies, shooting stars and rainbows. We rely on mirrors to see what we look like, and gleaming gemstones to impress or show affection to one another. Have you ever stopped to think that when we see any of these things, we are not directly connected to them? We are, in fact, seeing light — light that somehow left objects far or near and reached our eyes. Light is all that we can really see. Without light, our world would be nothing but absolute darkness.

When we think of light, we usually understand it as the thing or ‘wave’ that we perceive with our eyes. But what exactly is light? Many scientists are still trying to unravel its mystery. Light is made up of energy waves which vary in size from a few centimeters (radio waves) to one billionth of a meter (gamma rays). Light is sometimes referred to as electromagnetic radiation because it is made up of electric and magnetic fields. The reality is that visible light is only one thousandth of the whole spectrum. Light waves also come in many frequencies. The frequency is the number of waves that pass a point in space during a given time interval, usually one second. It is measured in units of cycles (waves) per second, or Hertz (Hz). The frequency of visible light is referred to as color, and ranges from 430 trillion Hz, seen as red for example, to 750 trillion Hz, seen as violet.

To go further into the mystery of light, we should note another phenomenon: light not only vibrates at different frequencies, it also can travel at different speeds and through different substances! Light waves move through a vacuum at their maximum speed, 300,000 kilometers per second or 186,000 miles per second, which makes light the fastest phenomenon in the universe. Amazingly, light slows down when it travels inside substances, such as air, water, glass or a diamond. The way different materials affect the speed at which light travels is the key to understanding the bending of light, or refraction, which enables us to develop lasers and fibre optics.

We have touched on some of the basic concepts of what light is but it is a mystery that even scientists are still puzzled by. One thing is certain and that is its importance in our everyday lives. For many, it is a given like air because of our reliance upon it. It feeds us by supplying energy to grow our food. It also affects us biologically as our lives are governed by night and day. Our brains are triggered by frequencies which produce in us the sensations of color. Have you ever thought of the affect that the color of a room has on your mood? Or how about the atmosphere created by candlelight? Our eyes have 125 million sensors that enable us to absorb light reflected from our surroundings. We can apparently discern up to 10 million shades of color! It’s amazing to imagine that your body seems to be designed to interact with light in some form or another.

Light can also be both life threatening and life giving. Extreme bright light can cause blindness. Waves produced by mobile phones have now been proven to be harmful. If earth’s atmosphere didn’t absorb the harmful frequencies of ultraviolet, x-ray and gamma rays, life would not be possible on earth. Prolonged, unprotected exposure to UV rays from sunbathing can increase the likelihood of skin cancer. On the other hand, brief exposure to UV’s can provide vitamin D, ‘the sunshine vitamin’. Laser surgery has become common in medicine as it can successfully treat cancer tumors as well as improving eyesight. We all know the psychological effect that a bright sunny day has on us!

One expert in communications technology once said that he believes ‘that light was made by God for communications’. Telecommunications scientists are just beginning to exploit the infinite amount of bandwidth found in a light beam. If we look at the impact that telephone, radio and TV, and more recently the Internet, have had on our lives-- it’s hard to imagine that the origin of light was just an accidental result of an explosion. It’s an everyday phenomenon that we take for granted but it permeates our reality and every scale of existence. From our technology to our spirituality, we are creatures of light!

I saw Eternity the other night,
Like a great ring of pure and endless light,
All calm, as it was bright;
And round beneath it, Time in hours, days, years,
Driv’n by the spheres
Like a vast shadow moved; in which the world
And all her train were hurled.
Henry Vaughan 1622–95; Silex Scintillans (1650–5) ‘The World’

This verse from the 17th century poet Henry Vaughan, speaks of a different aspect of light that Albert Einstein promulgated in his theory of relativity. This is the so called ‘particle’ concept of light which is difficult to explain and still leaves many physicists scratching their heads. If you were the light beam itself-the photon-traveling through space, you’d experience no time! To go further, if you could travel faster than the speed of light, theoretically, this means that you could see a moment in time before it actually takes place! I would like to examine these concepts in more depth in the next article, perhaps delving into the origin of the universe itself!

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