Why Doesn't the Earth's Air Fly Away?

Air is what keeps the planet healthy, happy and ultimately, alive. Yet what’s to stop this air from simply floating away into outer space? It’s a legitimate question which is why we’ve taken the time to put together an answer that shuns scientific jargon and explains the phenomenon in simple terms.

What is atmosphere?

To understand why the earth’s air doesn’t fly away it’s important to comprehend what exactly is meant by the word ‘atmosphere.’ Put simply, the earth’s atmosphere is a layer made up of a variety of gasses, including nitrogen, oxygen, argon, and carbon dioxide. Each gas is composed of atoms which weigh in at various levels of heaviness. The fact that these gas atoms have mass means that they’re subject to the laws of gravity.  

What is gravity?

To wrap your head around why the earth’s air doesn’t fly away you’ll also need to understand the concept of gravity. In the simplest terms possible, gravity refers to the force of attraction between particles or bodies that is proportional to their masses.

When compared to a nitrogen atom the earth has an extremely large mass. This is largely due to its liquid iron core which helps it to hold an atmosphere. Lack of mass is why Mercury doesn’t have an atmosphere! Magnetic fields also help keep atoms close by. The orbit of the moon pulls on the earth which gives it a more powerful magnetic field than other planets. This prevents the atmosphere from being stripped away by radiations from the sun.

Together these forces work to ensure that nitrogen atoms are pulled in close to the earth and forced to stay put, thus binding air to the planet. That said, not all atoms are retained which is why the earth’s atmosphere gets thinner with elevation.

The atmosphere is a fascinating phenomenon and has infatuated scientists for hundreds of years. In the article ‘Analysis of Heavy Metal in Ambient Air’ researchers investigate how exposure to heavy metals can trigger a range of human disorders and ecological damage. For this reason they stress that it’s vital to strictly limit and control emissions, particularly when it comes to heavy metals. These can enter the environment in a myriad of ways, with airborne emissions causing particular concern. Once they have infiltrated the atmosphere these pollutants are able to travel huge distances, thus transferring contaminants to ecosystems across the globe. As well as exploring the issue the article also looks at how Vlaamse Milieumaatschappij (VMM), the Flemish Environment Agency is using cutting edge technology to monitor airborne heavy metal pollution in Belgium.