Intro to Astronmy Article Example | Topics and Well Written Essays - 1000 words - 1

Intro to Astronmy - Article Example In 200 AD, astronomers believed that planets moved round the earth in small circles called the epicycle. The Heliocentric model later explained that all planets including the sun revolved around the sun. This model also explained that the retrograde motion of planets did so as the earth which moves faster than the other planets overtook the other planets. Other planets are categorized as superior or inferior to the earth. Time that is able to elapse between the configurations that are identical and consecutive is known as the synodic period. It was Copernicus who determined the sidereal period of other planets. He was also able to know the distance between the planets and the sun. Kepler was able to come up with a law that stated that every planet has an orbit that about the sun know as an ellipse. He also came up with the semi major axis. This happens to be the distance between the planets and the sun. The measure of the deviation from the perfect circle is known as the eccentricity. Kepler had three laws to explain the motion of planets and this was a major achievement in the field of astronomy. Galileo was able to discover a lot more with the aid of a telescope. He was able to know that the earth was not at the centre of the universe. With his telescope, he was able to know that the earth was not at the centre of the universe and that the earth was just like any other planet moving around the sun. Isaac Newton later came and introduced three laws. Inertia, force and action and reaction. He was also able to come up wi th the laws of the universal gravitation. The law of gravitation states that two bodies attract each other with a force directly proportional to each and every mass of the two bodies. This force is also inversely proportional to the square of the distance between them. Using the law of gravitation, Kepler’s three laws can be summed up. Newton’s was able to note that every

Analysis of Truman's Fair Deal Literature review

Analysis of Truman's Fair Deal - Literature review Example The Policy of Containment was devised in 1946 by George Kennan, then a high-ranking representative at the US embassy in Moscow. It consisted in limiting the expansion of the Soviet sphere of influence, both militarily and economically, in the hope of provoking the collapse of its social system. The Marshall plan was the economical part of this policy, whereas the creation of the North Atlantic Treaty Organization (NATO) in April 1949 was its military component. McCarthyism, a term coined by a political cartoonist in 1950 following the involvement of Senator Joseph McCarthy in a widespread "witch hunt" against Communists on American soil, corresponds to the excessive response to the fear of the spread of Communism following World War II. Also, termed the "Second Red Scare" (the first one having occurred just after the Bolshevik revolution in Russia in 1917), this period spanned roughly a decade from the end of the 1940s until the late 1950s. Characterized by its policy of systematic suspicion, it sparked a controversy that still exists today. It raised the issue of freedom of thought versus patriotism, and the term is still used to describe the unfounded questioning of a person's loyalty to the nation. As the number of white-collar positions increased and overtook that of professions dealing with the direct production of materials, a shift in the American population appeared in the 1950s. Most employees were leaving the industrial areas of the North and East of the USA to move to the South and West, were management-related positions were numerous and the environment more welcoming. This shift was accelerated by the development of Interstate highways that allowed the commuters to use their cars instead of the public transports, thus creating and developing a suburban way of life that didn't exist before. The Korean and Viet Nam wars had in common that they showed America's commitment to prevent the spread of Communism throughout the world, and not just in Europe. They were both limited wars that demonstrated that technical superiority is no guarantee for victory. Besides, neither they were popular at home among the general public. They differed in that the Viet Nam war had more important long-term repercussions on the American economy, politics, and public attitude toward the government. Â