The general context, however, suggests that it refers to the earth as it is lit by the sun. This method of changing referents is widely employed in the Qur'an when the change is easily noticeable when the subject matter is familiar. Here we have a discreet allusion to the fact that sunlight does reveal the earth and has a great effect on human life, as is well known. Our familiarity with the sun and his light makes us tend to overlook his beauty and function. This Qur'anic hint reawakens us to this magnificent daily spectacle.
Night time is like a screen that covers and hides everything.
It also has its own impressions on everyone, and its impact on human life is not less important than that of day time. When heaven is mentioned, our immediate thoughts go to the huge domelike sky above us in which we see the stars and the planets moving each in its orbit. But we are in fact uncertain of the exact nature of heaven. However, what we see above us does bear the idea of building and construction because it looks to us a firm and solid whole. As to how it is built and what keeps it together as it floats in the infinite space, we have no answer.