The sun illuminates the other side of the planet at night since it has a relatively fixed position in relation to the Earth. The Earth revolves around its axis in a tilted position and around the sun, creating the summer, winter, night and day effects.
The light seen on the moon at night is provided by the light of the sun reflecting off the moon and shining on the earth. When the sun and the moon are in the same spot in relation to the Earth, a solar or partial eclipse occurs, and people often travel to witness the rare event. The sun is composed of hydrogen, helium and other elements, and it creates nuclear fusion reactions within the core, transforming hydrogen into helium and gamma rays.