How did Eratoshenes Measured the Circumference of the Earth? Essay

About a matter of two cytosine decades ago, Greek astronomers valued the erudition that the shape of the populace is correspondingly a sphere. And as the moon passes through the shadow of the earth, or that which is called a lunar eclipse, the Greeks have observed the circular shadow casted by the farming. Since that time, it was already an realized intellect that only spherical objects cast a circular shadow, thus, the culture that the Earth is likewise spherical in shape. The mere conclusion of the Earths shape, nevertheless, did non achieve contentment to the Greeks.A Greek astronomer by the name Eratoshenes discovered a possible way in measuring the Earths circumference. It started when he had heard some reports from sensation of Egypts urban center, Syene, which was located on the equator of the earth. The reports have informed Eratosthenes that the sun shows good wells down on Syene during the first day of summer. However, the astronomer did not observe any similar phe nomenon anywhere by his home indeed he arrived at the supposition that in his home, Alexandria, which lies 7 degrees north of the city of Syene, the sun never does reach zenith.Eratoshenes further presupposed that the sun is in origin with the potential measurement of about 7 degrees south of his residencys zenith during summer solstice or the first day of summer. Provided such conclusion, the distance from Alexandria and Syene was believed to be 7/360 or 1/150 that of the circumference of the Earth ( a complete circle has a 360 degree measure). Additionally, way back Eratoshenes time, stade was the know standard unit of measurement, which then is equal to 1/6 of a kilometer.Consequently, there are 5,000 stades from Syene to Alexandria and from such logic, the Earths circumference was calculated to be 50 x 25,000 stades = 42,000 kilometers. Accordingly, the accepted modern value of the Earths circumference is 40,000 km, hence Eratosthenes was correct.ReferencesThe Earth and Moon, Size of the Earth cont. consequence retrieved on 10 Sept 2007 from http//inkido. indiana. edu/a100/earthmoon7. html