The Ozone Layer

 by Attish Das

We all know that there is an atmosphere surrounding planet Earth, but it is not as simple as it seems. There is actually six different layers in the atmosphere: The Troposphere, The Stratosphere, The Mesosphere, The Thermosphere, The Ionosphere and The Exosphere. First, lets look at what each layer has a role at.

The Troposphere.

This is the Earth’s most inner layer. It starts at the Earth’s surface from 8 to 14.5 kilometres high (which is about 5 to 9 miles high). This layer is the densest and hold almost all the weather.

The Stratosphere

The Stratosphere starts just above the Troposphere and extends to 50 kilometres (31 miles) high. The Ozone layer, which absorbs and scatters the solar ultraviolet radiation, is in this layer. We will get into more detail into the Ozone layer later.

The Mesosphere

This layer starts just on top of The Stratosphere and extends for an even higher amount of distance at 85 kilometres (53 miles) high. This layer is important because meteors usually burn up in this layer of the atmosphere.

The Thermosphere

The Thermosphere comes immediately after the Mesosphere and extends to an extremely high amount of 600 kilometres (372 miles) high. Auroras occur in this layer and satellites orbit the Earth in this layer. 

The Ionosphere

The Ionosphere is an abundant layer of electrons and ionized atoms and molecules that stretches from about 48 kilometres (30 miles) above the surface to the edge of space at about 965 km (600 mi), overlapping into the Mesosphere and The Thermosphere. This dynamic region grows and shrinks based on solar conditions. The Ionosphere is a critical link in the chain of Sun-Earth interactions. This region is what makes radio communications possible. 

The Exosphere

The Exosphere is the upper limit of the atmosphere. It extends from the top of the thermosphere up to 10,000 km (6,200 mi). 

A graph showing what things stay at each layer of the atmosphere

So, now going into the Stratosphere, what is the Ozone Layer?

Ozone is a naturally occurring gas found in the whole atmosphere where it absorbs most of the sun's ultraviolet light, which are invisible rays harmful to both plant and animal life in the form of skin cancer. 

Ozone is found in all the atmosphere including ground level but most Ozone, to be exact about 90 per cent) is found in a band which is called the Ozone Layer (about 15 to 30 kilometres high), which is in the Stratosphere, which is also the layer in which larger aircraft fly. There is a discussion whether it is really a 'layer' at all but one of loads of gases found in the Stratosphere. 

Some people do not know, but the Ozone Layer is essential for Life. Earth's Ozone Layer was formed around one billion years ago and, before that, there is a theory that the only life on Earth was at the bottom of the ocean in the form of single-celled organisms. There in the same theory it is thought that single-celled organisms released Oxygen through a process called photosynthesis. 

Now, Photosynthesis is the process in which green plants and some other organisms use sunlight to synthesise nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the green pigment chlorophyll and generates oxygen as a by-product. 

The photosynthesis equation is:

Carbon Dioxide + Water > (light) > Glucose + Oxygen 

In photosynthesis, Carbon Dioxide diffuses into the leaves through the stomata, tiny structures which close at night-time and open at daytime where it is then transported into the cells in the leaves of the plant, or sometimes the stem, into the chloroplasts where then photosynthesis occurs, generating previously mentioned Oxygen as a by-product. The Oxygen then diffuses out of the stomata. 

The other reactant of photosynthesis, water, is sucked up from the roots then is transported through the xylem, to the leaves of the plant or sometimes to the stem, where photosynthesis occurs in the chloroplasts of the cells. Glucose is made. Glucose is used by plants for energy and to make other substances like cellulose and starch. Cellulose is used in building cell walls.