The earth is the only planet in the universe that has life. One of the reasons why life exists on this planet is an encompassing blanket of gases called the atmosphere. It is like a blanket of air that protects the earth from the harmful rays of the sun. It also controls the temperature and, most important of all, it contains oxygen, which is essential for every form of life. This almost invisible blanket is kept intact around the planet by another invisible entity called gravity.
