The earth is surrounded by a layer of gas called the atmosphere. This thin blanket of air is an integral and important aspect of the planet. It provides us with the air we breathe and protects us from the harmful effects of the sun’s rays. The atmosphere extends up to a height of about 1,600 kilometers. The atmosphere is divided into five layers based on composition, temperature, and other properties. These layers starting from the earth’s surface are called the troposphere, the stratosphere, the mesosphere, the thermosphere, and the exosphere. The atmosphere is composed mainly of nitrogen and oxygen, which make up about 99 percent of clean, dry air. Nitrogen 78 percent, oxygen 21 percent, and other gases like carbon dioxide, argon, and others comprise 1 percent by volume. Oxygen is the breath of life while nitrogen helps in the growth of living organisms. Carbon dioxide, though present in a minimum amount, is important as it absorbs heat radiated by the earth, thereby keeping the planet warm. It is also essential for the growth of plants.