'The red colour of the sun (âditya) is the colour of fire, the white of water, the black of earth. Thus vanishes what we call the sun, as a mere variety, being a name, arising from speech. What is true are the three colours.

In plain words: The sun is also made of the red of fire, the white of water and the black of earth. "Sun" is just a name. The three basic parts are what is real.