The layer of gas that surrounds Earth is known as the atmosphere. Composed primarily of nitrogen (78%) and oxygen (21%), along with trace amounts of other gases such as carbon dioxide and argon, the atmosphere plays a crucial role in supporting life. It protects living organisms from harmful solar radiation, regulates temperature through the greenhouse effect, and facilitates weather patterns. The atmosphere is divided into several layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere, each with distinct characteristics. Understanding the atmosphere is essential for studying climate change and predicting weather patterns.