Ozone Layer
Written by Tega Jessa
The Ozone layer is the layer of of the atmosphere that protects the earth from UV rays. This is done because of a form of oxygen called ozone. Ozone is a rare form of oxygen that only forms in the lower part of the stratosphere. As a matter of fact the formation of ozone plays an important role in absorbing 93-99% percent of all UV rays from the sun. So how does the ozone layer work?
The process starts with normal oxygen molecules. If you remember from chemistry the normal oxygen molecule has two oxygen atoms. Ozone has three oxygen molecules but there is only way that this can occur naturally in nature. This is when an O2 is exposed to Ultraviolet Radiation. The oxygen molecule is broken down into atomic oxygen. The free oxygen then combines with the remaining O2 oxygen molecules to make ozone. This process helps to effectively absorb most of the UV radiation from the Sun. However, why is it important that UV radiation that reaches the earth's surface be limited?
The existence of life on Earth is almost a statistical miracle involving the Earth being the right distance from the Sun, being a rocky planet, having an atmosphere, and a sufficient amount of water. However the effects of radiation has been proven in the past to be lethal to the delicate food that has evolved to sustain life. The first victim of UV radiation would be the plankton in the world's oceans. Plankton is the very foundation of the food chain with millions of creatures both big and small relying on it for sustenance. Without their food source these sea creatures would die out and without them their predators would also starve. It is believed that a similar situation caused a massive extinction event that ended the Precambrian period of prehistory. So we see how even now that the absorption of UV rays by the Ozone layer is important.
Unfortunately the ozone layer is starting to be depleted due to air pollution and other factors. A major source of Ozone depletion has been the production of chlorofluorocarbons or CFC's. These were used in products that made use of spray cans. CFC's in the atmosphere break up in a similar process to ozone and produce free atoms themselves that interfere with the natural formation of ozone. As the serious consequences of this were realized nations acted to start reducing and eventually banning the use of CFC's
If you enjoyed this article, there are others on Universe today that you will be sure to enjoy. There is a great article on the composition of the atmosphere. There is also a great article on the atmosphere of the planets.
There is also great article and resources about the ozone layer online. There is a great article on NASA.gov. There is also great resources on Environmental Protection Agency's website.
You can also check out Astronomy Cast. Episode 151 Atmosphere is a very relevant episode.
Filed under: Astronomy
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