The sky is the expanse of air that surrounds the Earth, appearing blue during the day due to the scattering of sunlight by the atmosphere. It is home to various weather phenomena, including clouds, rain, and storms, which are influenced by atmospheric conditions. At night, the sky reveals a different view, showcasing celestial bodies such as stars, planets, and the Moon. The Milky Way galaxy can also be seen, along with other astronomical features. The sky plays a crucial role in Earth's climate and is essential for life, as it contains the oxygen we breathe.