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