Properties of Light

Properties of LightWhen you open your eyes in the morning, take a minute to thank God that you can see. We should reflect upon how good it is to have light instead of the darkness of night. The properties of light make it unique and special.

I am keenly aware of my gift of sight because of a long association with Glynn Langston, who is blind and manages our outreach to the visually impaired. In my lectures, I frequently refer to Edwin Abbott’s book Flatland to help people understand dimensions and how the spiritual is different from the physical. Glynn was born blind, so he is unable to visualize the concept of a sphere crossing a plane and leaving the outline of a circle. He has been kind about it, but my wife once said to me, “How do you expect a blind man to visualize anything!” Even those of us who can see have trouble understanding the properties of light beyond what meets the eye. Radio waves, gamma rays, X-rays, ultraviolet rays, and infra-red rays are all light!

The properties of light make it difficult to comprehend. The most general definition of light is that it is the energy released when a charge changes momentum. The bundle of energy released is called a photon, and the amount of change in momentum determines the energy of the released light. Even in the visible spectrum for humans, the different colors we see are determined by how much energy the light has. Violet has much more energy than red. Ultraviolet has more energy than violet. X-rays and gamma rays have even more energy, but they are still light. Infrared, and radio waves have lower energies than red. That is why infrared warms you and ultraviolet gives you a sunburn. It is also why radio waves can pass through the walls of your home without causing damage and gamma rays can also pass through things, but they will do significant damage.

In the creation process, there had to be special accommodations for the properties of light coming to Earth from the Sun and from outer space. The ozone layer had to be in place to absorb ultraviolet and avoid damage to life. The eyes of every living thing that uses some form of sight had to be designed to function in the part of the spectrum that fit its diet. Rattlesnakes, for example, have specialized sight organs to see in the infrared. Because they eat rodents whose bodies give off radiation in the infrared, a rattlesnake can see its prey on the darkest night. Nearly every insect sees some part of the spectrum other than the colors visible to humans. That is how a mosquito finds you and how insects navigate at night.

Not every star in the sky gives off the properties of light that are needed for life to exist. Some stars radiate in the X-ray part of the spectrum, and others radiate energies too low to be useful to life. Even our trees and shrubs require light in the green part of the visible spectrum to know when to shed their leaves in preparation for winter. In Job 38-41, God spoke to Job to show His wisdom and design and convince Job of his ignorance. Many of the designs God pointed to are connected to light. “Where is the way where light dwells, and where is the location of darkness?” (38:19) “By what process is light parted which scatters the east wind upon the earth?” (38:24) “How does the eagle seek the prey and see that which is afar off?” (39:29)

The Bible speaks of light that is not produced by the acceleration of an electric charge. The most important of these is described in Matthew 5:14-16: “You are the light of the world … let your light so shine before men that they may see your good works and glorify your Father which is in heaven.” Let those of us who are Christians not only be amazed by God’s design of the properties of light and the world in which we live, but let us also strive to be the light Jesus calls us to be.
— John N. Clayton © 2019

Best Animal Eye

Best Animal Eye
What is the best animal eye? Engineers at the University of Illinois have been researching that question. They have now built the world’s best camera by copying that animal. Their new camera could help military drones see camouflaged or shadowed targets. Their discovery also will allow surgeons to perform many kinds of operations more accurately. They have learned all this from the animal which possesses the best eye known to science. The best animal eye belongs to a small creature known as the mantis shrimp. Here are some of the ways the mantis shrimp’s eyes are superior to all others:

The eye of a mantis shrimp has a dozen different kinds of light receptor cells so they can sense properties of light invisible to other animals. Human eyes have only three types of light receptor cells.

The mantis shrimp eye can sense polarized light which has waves that undulate in one plane. Light reflecting off of a surface is always polarized. This ability allows the mantis shrimp to see objects that would otherwise be invisible because of blending into the background.

A mantis shrimp’s eyes are constructed so that each pixel has a rhabdom which is a rodlike structure made of light receptors. The rhabdoms have threadlike structures called microvilli alternately stacked at right angles. That means the shrimp has cells in the two hemispheres of the eye which are tilted 45 degrees to each other allowing their eyes to detect four polarization directions.

The eye of the mantis shrimp can detect an extensive range of light intensities of light to dark known as the dynamic range. This means that they can see clearly even when there is a very bright area next to a very dark area.

The mantis shrimp is the only animal that can sense a full spectrum of colors and can see the polarization of each color. That means that when there is a complicated background, the animal can still get a clear image.

Electrical and computer engineer Victor Gruev and his research team have already made a camera based on the best animal eye. It has a dynamic range which is about 10,000 times higher than today’s commercial cameras. Gruev and the team are working on a commercial version of their camera. Produced in bulk quantities the improved sensors would cost only $10 each.

There seems to be little doubt that this will be the camera of the future, and science has learned how to make it by studying the best animal eye of one of God’s smallest creatures.
–John N. Clayton © 2019

Data from Scientific American, February 2019, Page 12, or online HERE.
To see our earlier report on the mantis shrimp’s visual system click HERE.

See Through Objects

See Through Objects
How is it possible for us to see through objects (like air, water, and windows) and not through others (like wood, steel, and window blinds)?

Light is a form of electromagnetic wave energy oscillating in a particular frequency range and energy level. There are many more frequencies (and energy levels) in the spectrum of electromagnetic waves. X-rays are electromagnetic waves at a higher frequency than light. Radio waves from cell phones, radio, and Bluetooth devices are also electromagnetic waves at a lower frequency than light. We can’t see the waves that are above or below light frequencies because our eyes were not designed to see them.

We say that an object is opaque if we can’t see through it and transparent when we can see through it. When some light passes through an object, we say that it is translucent. Wood is opaque to visible-light frequencies, but it is transparent to electromagnetic waves in other frequency ranges. For that reason, we can listen to the radio or use our cell phones or wi-fi inside our houses. Our bodies are partially transparent to X-rays. That allows doctors to use X-rays to check for broken bones.

If our eyes were sensitive to radio waves and not light frequencies, we would be able to see through most solid objects. Then we would not only lose our car keys, but we would also lose our car–and our house too! The things we need to see would be invisible, and all of the electromagnetic waves around us would fill our vision with confusion.

Electromagnetic waves of different frequencies can pass through some materials but not others because of their wavelengths and the energy levels of the electrons in the atoms of the materials. So X-rays can pass through skin and muscle better than through bones. Radio waves can pass through wood, but not through steel. Light can pass through clear glass, but not wood or steel or cookie dough.

The complexity of this system allows us to see those things we need to see, like solid objects that our bodies cannot pass through. It also enables us to see through objects that we can pass through, like the air or water. It even allows us to see through objects which can protect us, like glass windows in our homes and cars. At the same time, it enables us to have cell phones, MRIs, and wireless headphones which use electromagnetic waves that can pass through objects without being seen. This very complex system took some incredible engineering by a Master Engineer.
–Roland Earnst © 2018

What Is Light?

What Is Light?
A question that scientists cannot fully solve is the nature of light. What is light? Is it a wave or is it a particle?

Light has wave properties. It travels in straight lines, but it can be reflected from objects like mirrors, or refracted as it travels through objects like water or glass. Different frequencies of light waves are bent in varying amounts by a prism to show the colors of the spectrum. Light, like sound waves, can travel through gases (air), through liquids (water), or through solids (glass).

But light can also do something that waves normally cannot do. Light can travel through empty space. Because of that and other properties of light, we say that light consists of particles called photons, which act as if they have mass. Photons can knock electrons out of crystals in what we call the photoelectric effect. That’s how solar panels generate electricity from sunlight. So light in motion seems to have mass since it can pass through a vacuum or knock electrons out of their orbit. However, when we stop light, it has no mass. If you shine a light on an object, the light doesn’t make the object any heavier.

What is light? While science ponders that question, we use light every day, and we couldn’t live without it. The question of how light can have properties of both a wave and a particle has baffled scientists for centuries. Even though that answer to that question may never be fully understood, we continue to enjoy and use it every day.

We can see that the simple phrase “let there be light” (Genesis 1:3) is an incredibly complex command.
–Roland Earnst © 2018

Why Are Plants Green?

Why Are Plants Green?
Why are plants green? The answer to this is some pretty basic physics.

The colors of light that we receive from the Sun have different energies. Red is the lowest of these energies followed by yellow, green, and blue. The sunlight with the highest energy that actually reaches the surface of the Earth is green. Blue light, which is more energetic, is refracted away by Earth’s atmosphere and scattered as it interacts with molecules in our upper atmosphere. That’s why the sky is blue.

When you look at an object, the color you see is the color reflected by that object. A red ball is red because it reflects red and absorbs all other colors. A green leaf is green because it reflects green and absorbs all other colors. If the highest energy of light reaching the surface of the Earth is green, and if the leaf reflects green, what does this do for the leaf? The answer should be pretty obvious – it keeps the leaf from absorbing too much energy and getting cooked. In the fall of the year when the leaves lose their chlorophyll A, which gives them the green color, what happens? The leaf gets cooked, falls off the tree, and we have to scrape it off the yard.

If a planet had a different atmosphere so that a different energy of light reached its surface, its plants would have to be a different color. To quote Kermit the Frog “It’s not easy being green.” Why are plants green? They are green because green is essential to life on Earth.

This explanation is greatly oversimplified. Obviously, not all plants have green leaves. Some plants live under a canopy of other trees and have to use a different system. The design of life on Earth is incredible, and the green trees and grass around us testify to the wisdom of God in making a place for life to exist.

We have a children’s book titled Why Is the Sky Blue, Why Is the Grass Green. You can read it and all of our children’s books on our Grandpa John’s Science Club site using THIS LINK.
–John N. Clayton © 2018

Color Vision Gender Differences

Color Vision Gender Differences
There are many differences between men and women, but you realize that there are color vision gender differences?

Light is electromagnetic radiation that stimulates our eyes. There are only specific frequencies of the electromagnetic frequency spectrum that we can see. Frequencies below the range of visible light are called infrared. We can sometimes feel infrared radiation as heat, but we can’t see it, although some animals can. Frequencies higher than visible light are ultraviolet which we can’t see, but it affects our skin and can cause sunburn. Some animals can see infrared light.

Within the visible spectrum of light that humans can see, different bands of frequencies affect our eyes differently. Most of us have receptors in our eyes for the wavelengths which we call red, green, and blue. When light stimulates those receptors, they send a signal to our brain which combines the signals to allow us to see many variations in colors.

People with colorblindness (mostly men) have one of those color receptor categories missing. The missing color may be either red or green. Why are men colorblind more often than women? The genes that encode the red and green receptors are located in the X-chromosome. Men have one X- and one Y-chromosome. Women have two X chromosomes. That means that if a man has a defective X-chromosome, he is out of luck. A woman would need to have two defective X-chromosomes to be colorblind.

It’s interesting that the chromosome pair that creates the sex differences also explains the color vision gender differences. God said, “It is not good for man to be alone” and He took something out of the man to create a woman. Then He put them together to complete each other. In many ways, men and women really do need each other to be complete.
–Roland Earnst © 2018