In the Word, “light” in the highest sense represents Divine Truth: knowledge, ideas, understanding that come to us from the Lord. In lesser degrees -- the light of a lamp, the light of the moon and so forth -- it represents lower levels of truth, ideas and understanding drawn from more earthly sources. Also, the sun in the Word represents the Lord, with its heat representing the divine love and its light representing the divine wisdom. That wisdom flows into our minds and enters our lives in the form of truth -- things we can know and ponder that lead us and help us to be good people. This connection between light and thought is one of many spiritual/natural relationships that's embedded in our common language. People “see the light” when they understand something; we try to “shed some light” by bringing new thoughts to a difficult question; people are “enlightened” when they get new information or a more complete understanding of something. And a light bulb in a cartoon represents an idea!

690. 16:8 Then the fourth angel poured out his bowl onto the sun. This symbolizes influx into the people's love.

To pour out the bowl symbolizes here, as before, an influx springing from goods and truths, here an influx into the people's love; for the sun symbolizes the Lord's Divine love, and in an opposite sense a love of self (nos. 53, 383, 414). Here it is a love of self, because we are told next that people were scorched with fire, and scorched with great heat, which symbolizes the lusts of that love.