Saturday, March 21, 2020
rain forrsest essays Rain forests may be grouped into two major types: tropical and temperate. Tropical rain forest is evergreen trees that form a closed canopy, below which is found a zone of vines and epiphytes where plants grow on trees, a relatively open forest floor, and a very large number of species of both plant and animal life. The largest trees have buttressed trunks above the continuous canopy, while smaller trees form a layer of more shade-delicate species beneath the upper canopy. The maximum height of the upper canopy of tropical rain forests is usually around 100 to 165 ft, with some individual trees rising as high as 200 ft above the forest floor. Conifers such as redwood and Sitka spruce tend to predominate in North America, while their counterparts in the southern hemisphere include various species of eucalyptus, Araucaria and Nothofagus. Th rain forest is home to many species of rare animals and plants. In the past and present history it has also been the home of over one hundred and twenty over the counte r prescriptions. All of this information has brought up the question that is on many minds, Should economic organizations, buisnesses and individual governments be allowed to continue the use and at times the abuse of the brazilian rain forest? Is economic advancement more important than the preservation of the rainforest. This is why we are the government has called on us. To find the facts and give it how it should be. Medicinal uses of the rain forests are a huge part of everyones lives. The rain Forrest has over 120 over the counter prescriptions and has made 12 billion dollars in sales. They say that the tropical rainforests cover seven percent of the earth and hold just about half of the world's animals. Also there is data that there may be about ten percent of useful Amazon plants now, and scientist's think that also there may be a cure for the AIDS ...
Wednesday, March 4, 2020
Geodesy and the Earths Size and Shape Earth, with an average distance of 92,955,820 miles (149,597,890 km) from the sun, is the third planet and one of the most unique planets in the solar system. It formed around 4.5 to 4.6 billion years ago and is the only planet known to sustain life. This is because of factors like its atmospheric composition and physical properties such as the presence of water over 70.8% of the planet allow life to thrive. Earth is also unique however because it is the largest of the terrestrial planets (one that have a thin layer of rocks on the surface as opposed to those that are mostly made up of gases like Jupiter or Saturn) based on its mass, density, and diameter. Earth is also the fifth largest planet in the entire solar system. Earths Size As the largest of the terrestrial planets, Earth has an estimated mass of 5.9736 Ãâ" 1024 kg. Its volume is also the largest of these planets at 108.321 Ãâ" 1010km3. In addition, Earth is the densest of the terrestrial planets as it is made up of a crust, mantle, and core. The Earths crust is the thinnest of these layers while the mantle comprises 84% of Earths volume and extends 1,800 miles (2,900 km) below the surface. What makes Earth the densest of these planets, however, is its core. It is the only terrestrial planet with a liquid outer core that surrounds a solid, dense inner core. Earths average density is 5515 Ãâ" 10 kg/m3. Mars, the smallest of the terrestrial planets by density, is only around 70% as dense as Earth. Earth is classified as the largest of the terrestrial planets based on its circumference and diameter as well. At the equator, Earths circumference is 24,901.55 miles (40,075.16 km). It is slightly smaller between the North and South poles at 24,859.82 miles (40,008 km). Earths diameter at the poles is 7,899.80 miles (12,713.5 km) while it is 7,926.28 miles (12,756.1 km) at the equator. For comparison, the largest planet in Earths solar system, Jupiter, has a diameter of 88,846 miles (142,984 km). Earths Shape Earths circumference and diameter differ because its shape is classified as an oblate spheroid or ellipsoid, instead of a true sphere. This means that instead of being of equal circumference in all areas, the poles are squished, resulting in a bulge at the equator, and thus a larger circumference and diameter there. The equatorial bulge at Earths equator is measured at 26.5 miles (42.72 km) and is caused by the planets rotation and gravity. Gravity itself causes planets and other celestial bodies to contract and form a sphere. This is because it pulls all the mass of an object as close to the center of gravity (the Earths core in this case) as possible. Because Earth rotates, this sphere is distorted by the centrifugal force. This is the force that causes objects to move outward away from the center of gravity. Therefore, as the Earth rotates, centrifugal force is greatest at the equator so it causes a slight outward bulge there, giving that region a larger circumference and diameter. Local topography also plays a role in the Earths shape, but on a global scale, its role is very small. The largest differences in local topography across the globe are Mount Everest, the highest point above sea level at 29,035 ft (8,850 m), and the Mariana Trench, the lowest point below sea level at 35,840 ft (10,924 m). This difference is only a matter of about 12 miles (19 km), which is quite minor overall. If the equatorial bulge is considered, the worlds highest point and the place that is farthest from the Earths center is the peak of the volcano Chimborazo in Ecuador as it is the highest peak that is nearest the equator. Its elevation is 20,561 ft (6,267 m). Geodesy To ensure that the Earths size and shape are studied accurately, geodesy, a branch of science responsible for measuring the Earths size and shape with surveys and mathematical calculations is used. Throughout history, geodesy was a significant branch of science as early scientists and philosophers attempted to determine the Earths shape. Aristotle is the first person credited with trying to calculate Earths size and was, therefore, an early geodesist. The Greek philosopher Eratosthenes followed and was able to estimate the Earths circumference at 25,000 miles, only slightly higher than todays accepted measurement. In order to study the Earth and use geodesy today, researchers often refer to the ellipsoid, geoid, and datums. An ellipsoid in this field is a theoretical mathematical model that shows a smooth, simplistic representation of the Earths surface. It is used to measure distances on the surface without having to account for things like elevation changes and landforms. To account for the reality of the Earths surface, geodesists use the geoid which is a shape that is constructed using the global mean sea level and as a result takes elevation changes into account. The basis of all geodetic work today though is the datum. These are sets of data that act as reference points for global surveying work. In geodesy, there are two main datums used for transportation and navigation in the U.S. and they make up a portion of the National Spatial Reference System. Today, technology like satellites and global positioning systems (GPS) allow geodesists and other scientists to make extremely accurate measurements of the Earths surface. In fact, it is so accurate, geodesy can allow for worldwide navigation but it also allows researchers to measure small changes in the Earths surface down to the centimeter level to obtain the most accurate measurements of the Earths size and shape.