# The mass of the atmosphere

What is the mass of the Earth's atmosphere? On each square centimeter of the Earth's surface air presses with a force about a kilogram. The Earth's atmosphere is made of such air columns. So, how many square centimeters comprises a surface of our planet, this is **the mass of the atmosphere**. It is known that the earth's surface is equal to 510 million sq. km.

In the square kilometer 10^{10} square centimeters. In the entire surface of the globe is, therefore, 51*10^{7} is multiplied by 10^{10} = 51*10^{17} square centimeters. Translating in tons, we get: 51*10^{17}/1000 = 51*10^{17}/10^{3} = 51*10^{14} tons!!!

The mass of the atmosphere can be calculated in other ways. The air column with a cross section equal to one, and unlimited high altitude is:

where ρ – the air density. Using the basic equation of statics:

where ρ_{0} and T_{0} – the density and temperature of the air at the earth's surface, µ – molecular weight of air, H – height of the homogeneous atmosphere. Using this formula, the mass of the atmosphere is obtained 5,3*10^{15} tons.

The mass of the Earth is 6*10^{21} tons. Dividing the mass of the Earth on the mass of the atmosphere, we get the approximate number of 10^{6} tons. The air mass is one-millionth of the mass of the globe! In addition, it is 250 times less than that of the hydrosphere (waters of the oceans). In the lower 5,5 km it contained 50% of the mass of the atmosphere within the first 36 km – 99%.