Last Updated on August 3, 2021 by Neil Mackengie
One of the great mysteries of the world in which we live in the light. We still do not know exactly what it is. It can only be described in terms of what it does. We know the light is a form of energy. Like some other forms of energy—heat, radio waves, and X-rays—the speed, frequency, and length of its waves can be measured. Its behavior in other ways makes it similar to these other forms of energy, too.
We know the speed of light. It travels at about 186,000 miles per second. This means that in a year, a beam of light travels 5,880,000,000,000 miles. That is the distance which astronomers call a “light year”, and it is the unit used to measure distances in outer space.
In trying to understand what light is and how it travels, many theories have been developed. In the seventeenth century, Sir Isaac Newton said that light must be made up Of “corpuscles”, somewhat as tiny bullets shot from the light source. But this “corpuscular” theory of light could not explain many of the ways in which light behaves.
At about the same time, a man named Christian Huygens developed a “wave theory” of light. His idea was that a luminous or lighted particle started pulses or waves, much as a pebble dropped into a pool makes waves.
Whether the light is waves or corpuscles was argued for nearly 150 years. Gradually, as certain effects of light became known, the idea of light corpuscles died out. Scientists now believe that light behaves both as particles and as waves. Experiments can show either idea to be true. So we simply cannot give a complete answer to “What is light?”
What Are The Three Ways Light Travels?
Light can travel in three ways from a source to another location: (1) directly from the source through empty space; (2) through various media; (3) after being reflected from a mirror.
When light travels, it has to do so against a backdrop of space. It’s not possible for light to travel through the vacuum of space. Is there any way that light can travel forever? Yes, there are two ways: 1) Light can travel in the vacuum of space. It can travel in a time-like manner against the backdrop of space. This is the way that our universe is described. It’s what we call Einstein’s Theory of Relativity. 2) Light can be created in a vacuum of space. This is called the “Big Bang” Theory. It was this way at the beginning of our universe. The question is how does the universe keep going? The answer is: a new light source has to be created
The concept of “black” and “white” light is incorrect in the case of sunlight. Light in the spectrum has both a red and a green component. (This is also the case for any other color of light.) The answer to the question is yes, light can be straight or “white”. In fact, a beam of wide-angle white light will contain less of the red and green components than a beam of “straight” light and will look whiter than a beam of narrow light.
The fastest thing in the world, by a huge margin, is a bullet. It has been measured traveling at over 11,000 miles per hour (5.9 million kilometers per hour), or about 1/5,000th of the speed of light.