Blessed is He Who has made galaxies in the sky and made in it (the sun as) a lamp, and a radiant moon (reflecting sun light).
See word No. 778 and Vs No. 15:16 for ‘Burooj’ meaning ‘Galaxies’. The sun is rightly called a lamp giving light and heat. Just like a lamp in which the oil burns to give light and heat, in the sun, hydrogen burns to give light and heat and the moon reflects the light of the sun. These 3 words ‘Burooj’ ‘Siraj’ and ‘Muneera’ beautifully describe their functions. Allah (SWT) keeps on rotating the earth giving rise to day & night alternately.