Light makes life possible. It powers the miracle of photosynthesis, allowing green plants to take water and carbon dioxide from the air and turn it into food. Sunlight warms the earth, preventing our water planet from turning into one huge ice cube. Cycles of light measure our days, and influence the behavior of most organisms on earth. Changes in daylength signal flowers to bloom.
Light tells animals when to mate, migrate, or hibernate.
It tells birds when to nest, and it affects our moods. A time to be born, and a time to die. A time to plant, and a time to reap. A time to weep, and a time to laugh. A time to embrace, and a time to refrain from embracing.