The source of light coming from stars in the sky is primarily the process of nuclear fusion occurring in their cores. Stars are massive balls of hot, glowing gases, predominantly hydrogen and helium. In their cores, the intense gravitational forces and high temperatures cause hydrogen atoms to undergo nuclear fusion, where they combine to form helium. This fusion process releases an enormous amount of energy in the form of light and heat.
The energy produced through nuclear fusion radiates outward from the star's core, gradually making its way to the surface. Once the energy reaches the surface, it is emitted as electromagnetic radiation across a wide spectrum, including visible light. This emitted light travels through space and reaches our eyes as starlight, enabling us to observe and appreciate the beauty of the night sky.
It's worth noting that stars emit light in various colors, depending on their temperatures. Hotter stars appear bluish or white, while cooler stars may appear reddish or orange. The combination of different stars with their varying temperatures, distances, and brightness levels creates the stunning array of lights we see when we look up at the night sky.