Shadow is the perfect example of a Bible study that had multiple reasons to start it. The first is the phrase “in the shadow of your wings”. The second is the from the Tolkien trilogy Lord of the Rings. Then the “science teacher” kicked in and I remembered that shadows are naturally occurring things. The metaphors then divided the writer part of me, requiring that the light and dark side of this come forth. Yes, there will be several posts from this thought.
The science part first. Shadows occur because there is a light source strong enough to cause one. A solid object blocks the light and as the rays respond to the object a shadow is formed. The brightness of the light, the size of the object, and the distance that separates them determine the shadow.
Earth’s shadow is the biggest one we deal with every day; you know it as night. We tend to not think of night as a shadow, but the earth is blocking the sun’s light rays from us. During the night we are in the umbra of its shadow. That is the darkest part. Loosely, we could call dawn and dusk the penumbra, or the lighter part of a shadow. The light-scattering properties of the atmosphere also come into play at these times of the day.
You may not always see a penumbra, but it is there. It may only be a thin lighter part that rings the main shadow, but it is present. If the source is bright enough our eyes may have a hard time picking it out, and it may not be very wide.
Unless you are Peter Pan, shadows are very obedient and follow your every movement. They will resemble the object that is blocking the light, but it may not be a perfectly clear image. The penumbra will add to the haziness of an exact match. The surface you view the shadow on will also affect its appearance. As the angle of the light changes to the solid object, so will the umbra.
In dusk and dawn, the color of things will appear different. This is because of the amount of available light that enters our eyes and activates the cones and rods of the retina. A very simple idea needs to be said here. You will not see your shadow if you are facing the light, it is there but you have to look for it.
Questions for you: What is the third type of shadow called? What common item has umbra as part of its name?