Do you not contemplate the expression of the work of your Lord? When it astounds you and prompts you to express in amazement your observation. Or how He extend the shadow and if He desired, He would have certainly caused it to be standing firm. Then We made the sun a proven indication upon the existence of the shadow.
Notice the shadow if it is dense enough or large enough it can cause darkness. The night is a shadow it is caused by one side of the earth turning away from the sunlight. That darkness remains until that side of the earth turns toward the sunlight.
The same is for the individual who turns away from the light of revelation and dwells in the darkness of ignorance. They remain there until they turn toward the light of truth and it reveals the darken shadows of falsehood.