Temperatures in the Earth’s near and outer atmosphere

The Sun is the most prominent feature and source of heat in our solar system. It is the largest object and contains approximately 98 percent of the total solar system mass. Scientists say one hundred and nine Earths would be required to fit across the Sun’s disk, and its interior could hold over 1.3 million Earths. The Sun’s outer visible layer is called the photosphere and has temperatures that go over 6,000°C (11,000°F). This layer has a mottled appearance due to the turbulent eruptions of energy at the surface. Solar energy is created deep within the core of the Sun. It is here that the temperature (15,000,000° C; 27,000,000° F) and pressure (340 billion times Earth’s air pressure at sea level) is so intense that nuclear reactions take place. This reaction causes four protons or hydrogen nuclei to fuse together to form one alpha particle or helium nucleus. The alpha particle is about .7 percent less massive than the four protons. The difference in mass is expelled as energy and is carried to the surface of the Sun, through a process known as convection, where it is released as light and heat. Energy generated in the Sun’s core takes a million years to reach its surface. Every second 700 million tons of hydrogen are converted into helium ashes. In the process 5 million tons of pure energy is released; therefore, as time goes on the Sun is becoming lighter. The chromosphere is above the photosphere. Solar energy passes through this region on its way out from the center of the Sun. Faculae and flares arise in the chromosphere. Faculae are bright luminous hydrogen clouds which form above regions where sunspots are about to form. Flares are bright filaments of hot gas emerging from sunspot regions. Sunspots are dark depressions on the photosphere with a typical temperature of 4,000°C (7,000°F). The Sun is said to have been active for 4.6 billion years and has enough fuel to go on for another five billion years or so. At the end of its life, it’s said that the Sun will start to fuse helium into heavier elements and begin to swell up, ultimately growing so large that it will swallow the Earth. After a billion years as a red giant, it is said that it will suddenly collapse into a white dwarf, the final end product of a star like ours. It is said also by scientists that it may take a trillion years to cool off completely. The layers of atmosphere. The Earth’s atmosphere is a thin layer of gases that surrounds the Earth. It is composed of 78% nitrogen, 21% oxygen, 0.9% argon, 0.03% carbon dioxide, and the remainder is composed of other gases. This thin gaseous layer insulates the Earth from extreme temperatures; it keeps heat inside the atmosphere and it also blocks the Earth from much of the Sun’s incoming ultraviolet radiation. The Earth’s atmosphere is about 480 km thick, but most of the atmosphere (about 80 percent) is within 16 km of the surface of the Earth. There is no exact place where the atmosphere ends; it just gets thinner and thinner, until it merges with outer space. At sea level, the air pressure is about 14.7 pounds per square inch. As your altitude increases (for example, if you climb a mountain), the air pressure decreases. At an altitude of 10,000 feet, the air pressure is about 10 pound per square inch and there is less oxygen to breath. Earth’s atmospheric layers. Thermosphere: The thermosphere is a thermal classification of the atmosphere. In the thermosphere, temperature increases with altitude. The thermosphere includes the exosphere and part of the ionosphere. The exosphere is the outermost layer of the Earth’s atmosphere. The exosphere goes from about 640 km high to about 1,280 km. The lower boundary of the exosphere is called the critical level of escape, where atmospheric pressure is very low (the gas atoms are very widely spaced) and the temperature is very low. The ionosphere starts at about 80-470 km high and continues for hundreds of kilometres (about 640 km). It contains many ions and free electrons (plasma). The ions are created when sunlight hits atoms and tears off some electrons. Ends