When we look at the sky, we see a vast expanse that can change throughout the day. During the day, the sky appears blue due to the scattering of sunlight by the atmosphere. We may also observe clouds, which are made of tiny water droplets or ice crystals, and can indicate different weather conditions. At night, the sky transforms into a dark canvas filled with stars, planets, and sometimes the Moon. The stars are distant suns, while planets like Mars and Jupiter reflect sunlight. Occasionally, we might see meteors or the Milky Way, a galaxy that contains our solar system.