God is the Light
God and Jesus become the light of the world.
There is no need for the sun or the moon.
Light is pure energy.
Background Reading:
Revelation 21:22-25
GOD IS THE LIGHT
22 I did not see the temple in the city, because the Lord God Almighty and the Lamb are its temple. 23 The city does not need the sun or the moon to shine on it, for the glory of God gives it light, and the Lamb is its lamp.