Our world’s sun is not visible in heaven, and neither is anything that is derived from it, since all that is natural. Nature, in fact, begins with that sun, and whatever is produced by it is called natural. The spiritual reality in which heaven exists, though, is above nature and completely distinct from anything natural. They communicate with each other only through correspondences.
The nature of the distinction can be gathered from what was said above about levels in Section 38, and the nature of the communication from the last two chapters about correspondences.
However, even though neither this world’s sun nor anything derived from it is visible in heaven, there is a sun there; there is light and warmth, there are all the things we have in our world and many more—not from the same origin, though, since things in heaven are spiritual while things in our world are natural.
Heaven’s sun is the Lord; light there is the divine truth and warmth the divine good that radiate from the Lord as the sun. Everything that comes into being and manifests itself in the heavens is from this source. We will discuss the light and warmth and the things that arise from them in subsequent chapters; here we restrict ourselves to the sun.
The reason the Lord in heaven appears as the sun is that he is the divine love from which all spiritual things come into being—and, through the agency of our world’s sun, all natural things as well. That love is what shines like a sun.
from Heaven and Hell, Sections 116,117