What is the light of heaven?

Is the repeated dwelling by sacred writers upon the white light merely imagination and coincidence?

The White Light, proceeding from the Great White Throne, the New Jerusalem, which has no need of the sun, neither of the moon, for the glory of God does lighten it, and in the transfiguration, the garments white, as no fuller on earth could white them, for as he prayed, the fashion of his countenance was altered and his raiment was white and glistering.

And behold, there talked with him two men, which were Moses and Elias, who appeared in glory.

Was it indeed only a sunstroke, that light from heaven, which blinded Paul and smote him to the earth, as he journeyed toward Damascus, so searching his conscience that it revolutionised the whole tenor of his work and life?

Light on the Hidden Way