تجربة عامة

Earth’s atmosphere

Planet Earth is surrounded by a layer of gases called the atmosphere. These create an essential blanket for life on Earth, keeping the planet at a comfortable temperature and protecting the surface from the Sun’s rays. Earth’s atmosphere is made up of several distinct layers. There is no clear boundary to the outer edge of the atmosphere—it just fades into space. The lowest layer, called the troposphere, forms the air we breathe. The air consists mainly of two gases—nitrogen (78 percent) and and oxygen (21 percent).