Earth Due To The Sun's Light example essay topic

The Sun is the central object of the solar systems and the largest as it contains 99.9% of the total mass of the solar system. It outweighs everything else in the solar system combined by a factor of one thousand. (The Comic Perspective) The Sun is the closest star to the earth. The strong gravitational pull of the Sun holds the Earth and the other planets within the solar system in orbit. The light and heat from the sun affects all of the objects in the solar systems and even allows life to exist on Earth. The Sun is just massive compared to the other planets in the solar systems.

The radius is about 109 times as large as Earths radius. (Encarta. com 2003) If the Sun were hollow, a million Earth would fit inside of it. Despite this massive size, the Sun has a lower density than Earth. The average density is only a quarter of the average density of Earth.

The Sun produces a ton of light. It looks small when looking at it from Earth and that is because it is so far away. The average distance from the Earth to the Sun is 93 million miles. Light from the Sun takes about 8 minutes to reach Earth. This light is still strong because the Sun is much closer to Earth than any other star and this keeps us from seeing any other stars during the day. Earth would not have any life on it without the Sun because it provides heat and light.

This is what warms out days and lights up our skies. This heat and light is what green plants live and grow and turn to food. Animals eat these plants for nourishment and human eats vegetables and things that grow in the Earth due to the Sun's light also for nourishment. The plants also give off oxygen that life on Earth lives and as a result all life relies on the Sun's presence. The Sun also heats Earth's oceans and land, which in turn heats the air and makes it circulate within the atmosphere.

As we can see, without the Sun, life on Earth could not exist. Currently, the mass of the sun currently is about 75% hydrogen 25% helium. I say currently because this amount changes slowly over time as the Sun converts hydrogen to helium in its core. The outer layers of the Sun exhibit differential equator, meaning a the Sun's equator the surface rotates once every 25.4 days; near the poles it's as much as 36 days.

(SEDS 2003) This oddity is because the Sun is not a solid body like the Earth. Similar effects are seen in the gas planets which are Jupiter, Saturn, Uranus, and Neptune. The differential rotation extends considerably down into the interior of the Sun but the core of the Sun rotates as a solid body. The conditions of the Sun at its core are very intense. The temperature is 15.6 million Kelvin and the pressure is that of about 250 billion atmospheres. At the center of the core the Sun's density is more than 150 times that of water.

The Sun's energy output is produced by nuclear fusion reactions. Each second about 700,000,000 tons of hydrogen is converted to about 695,000,000 tons of helium and 5,000,000 tons of energy in the form of gamma rays. (SEDS 2003) As it travels out toward the surface of the Sun, the energy is continuously absorbed and re-processed at lower and lower temperatures so that by the time it reaches the surface, it is primarily light. The surface of the Sun, called the photosphere is at a temperature of about 5800 K. Sunspots are cool regions and are only about 3800 K and they can be very large, as much as 50,000 km in diameter. Sunspots are caused by complicated and not very well understood interactions with the Sun's magnetic field.

The photosphere is the part of the Sun that we see with out eyes. It is the Sun's lower atmosphere and is a few hundred miles thick. It gives off most of it's every as light and heat. (SEDS 2003) The outer layers of the Sun are the chromosphere and the corona. The chromosphere is a thin layer about 1,200 to 1,900 miles thick, just above the visible photosphere. The chromosphere's temperature rises from about 9950^0 F near the photosphere to about 17,500^0 F near the corona.

The corona is the very hot layer of the solar atmosphere that is above the chromosphere layer. It extends to Earth and beyond as the solar wind. The Sun's temperature rises to 4 million degrees F at the bottom of the corona, and remains almost that hot as it reaches Earth. The Sun is about 4.5 billion years old. Since its birth it has used up about half of the hydrogen in its core. It will continue to supply light and heat for another 5 billion years or so.

Eventually it will run out of hydrogen fuel and it will then be forced into radical changes which, could result in the total destruction of the Earth. The Sun will grow brighter as time goes on and more helium builds in its core, therefore increasing the temperature. In approximately 3 billions years, the Sun will be hot enough to basically boil the Earth away. This is a scary thought, but this is the evolution of the solar systems.