Horace and the Atmosphere
Hey there! I don't know who's reading this, but have I got a story to tell you! My name is Horace and I'm a 5 billion-year-old rock. Now wait a minute! I know what you're thinking, "What a boring life. What does a rock know about anything?" But don't walk away yet. An old rock can know more than you think and I happen to have a pretty cool story to tell you. It's all about the atmosphere. You know, that big mass of gases and air pressure extending over 100 kilometers above your head. See, back when I was a baby rock at only 400 million years old, the world was extremely different from today. Not only was there no life, but the atmosphere was virtually non-existent. Let me explain in the first part of my story: The History of the Atmosphere.
Like I said before, the atmosphere was a very different place 4.6 billion years ago. It was a reducing atmosphere made of primarily methane, ammonia, and other toxic gases. Not much happened with the atmosphere until about 1 billion years later. The sun was kind of restless then and it triggered chemical reactions among the gases in air. These gases include the methane and ammonia in the air. This formed new materials and gases like nitrogen, hydrogen, water vapor, and carbon dioxide. What was left over of the methane and ammonia conveniently vanished. The most important new material was the water vapor that was formed by reaction and expelled by the volcanic earth. It allowed for the formation of clouds, which, in turn, produced rain. Over thousands of years, the rain accumulated to make rivers, lakes, and ocean basins. Now the earth finally had the tools to support life.
The first examples of this were the microscopic organisms that formed in the ocean. They survived because the ocean protected them from ultraviolet radiation.
Then there was the formation of another important part of the atmosphere, the ozone. Water vapor was broken down to form hydrogen and oxygen, which formed the ozone. The ozone lies 30 kilometers above the surface of Earth and is one of the most important layers, because it absorbs harmful ultraviolet radiation from the sun. Because of this protection, blue-green algae appeared. Then through photosynthesis even more oxygen began to appear. That was the start of the Earth's atmosphere as we recognize it today and is the reason we live and breathe. That leads us to the next part of my story: The Present Atmosphere.
78% of today's atmosphere is composed of nitrogen. The nitrogen cycle is how nature supplies all of the needed nitrogen for living things. Another 21% of the atmosphere is composed of oxygen. Oxygen is essential for human life on Earth. You humans get most of your oxygen from plants. They need carbon dioxide, so they get it from you through respiration. That is the cycle that plants and animals share. The rest of the atmosphere is composed trace gases like argon, neon, helium, krypton, and xenon. Some of these gases have practical uses. Neon is used in neon lights and bulbs, helium is used in blimps and balloons, and argon used in light bulbs in small amounts.
The atmosphere also has many layers to it. These layers are called the troposhpere, tropopause, stratosphere, mesosphere, thermosphere, ionosphere, exosphere, and magnetosphere. The tropsphere contains 75% of the gases in the atmosphere. This is where all the weather occurs on Earth and where everything lives. The tropopause is located at the top of the troposhpere and separates the troposphere from the stratosphere. We also find the jet stream here. The stratosphere is located above the tropopause. Here the temperatures remain fairly constant. The ozone layer is here too. After that is the mesosphere. The mesosphere is the coldest part of the atmosphere, but ironically most meteoroids are burnt up in this layer. Next comes the thermosphere. The air here is very thin and hot. The thermosphere is so hot because ultraviolet radiation is turned to heat. Temperature can reach up to 2000 degrees Celsius. The thermosphere has two parts. The first is the lower part, or the ionosphere. Here gas particles absorb X-ray and ultraviolet radiation from the sun.. These particles of gas then become ions. This helps radio communication because radio waves are bounce off the ions and reflect back to Earth. Sometimes though solar flares can increase the number of ions and interfere with the transmission of some radio waves. The exosphere comes next. This is the upper part of the atmosphere where the air is very thin and satellites orbit the Earth. Finally, there is the magnetosphere. The Earth's magnetic field operates in this layer. It is made up of negatively charged electrons and positively charged protons. The particles of the sun get trapped here and make up the Van Allen belts. These belts are important because they trap deadly radiation. When large amounts of radiation are given off from the sun during a solar flare, the particles collide with each other and cause the northern lights or aurora borealis.
All these elements and layers make up today's beautiful, clean atmosphere. Well, partially clean anyway. You humans are expelling tons of toxic gases into the atmosphere everyday with your cars, factories, and everyday products. If not corrected, these effects could be a serious problem to life as we know it. That brings me to the final part of my story: The Future of the Atmosphere.
The future of the atmosphere stands uncertain. There are many aspects such as ozone depletion, air pollution, and global warming. They are all related in certain ways and are all serious problems. CFC's (Chlorofluorocarbons) in the upper atmosphere threaten to tear other holes in the ozone layer besides just the one above Antarctica. As far as air pollution goes, everyday there is a multitude of carbon dioxide and carbon monoxide being expelled from our cars and factories as shown above. These poison gases are what have turned the air in Los Angeles a darker color and everyday accumulate to cause things like acid rain. This also ties in with global warming. The carbon monoxide and carbon dioxide in the atmosphere traps in the heat that the sun gives to the Earth. This blanket effect or greenhouse effect is causing temperature levels to rise all around the world. One of the real problems about all these things is that they all involve things we use in our everyday lives like cars, aerosols and production factories. That makes them harder to get rid of. The real future of the atmosphere though, depends on you humans. It will be a tough road, but if you continue to fight these problems, you just may give the atmosphere a future to have.