He studied the stars. Inc. Light and Shadow Light can shine through some liquids, such as water. Light can shine through some solids, such as glass. Water and glass are transparent. Most solid objects are not transparent.
Most solid objects block the light.
When something blocks the light, we see a shadow. The earth's light comes from the sun. The earth turns on its axis. The sun is always shining on part of the earth. But part of the earth is always in shadow.