How did Eratoshenes Measured the Circumference of the Earth? Essay

About a matter of two hundred decades ago, Greek astronomers valued the erudition that the conformation of the res publica is correspondingly a sphere. And as the moon passes through the butt of the earth, or that which is called a lunar eclipse, the Greeks control observed the circular behind commited by the commonwealth. Since that time, it was already an established intellect that only spherical objects cast a circular shadow, thus, the conclusion that the Earth is likewise spherical in shape. The mere conclusion of the Earths shape, nevertheless, did not achieve pleasure 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 one of Egypts city, Syene, which was located on the equator of the earth. The reports have informed Eratosthenes that the sun shows vertical wells down on Syene during the outset daytime of summer. However, the astronomer did not observe any similar phenomenon anyplace by his home therefore he arrived at the supposition that in his home, Alexandria, which lies 7 stagecoachs north of the city of Syene, the sun never does reach zenith.Eratoshenes get ahead presupposed that the sun is in line 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/ one hundred fifty that of the circumference of the Earth ( a complete circle has a 360 degree measure). Additionally, way back Eratoshenes time, stade was the known standard unit of measurement, which then is adapted 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 recognized modern value of the Earths circumference is 40,000 km, hence Eratosthen es was correct.ReferencesThe Earth and Moon, Size of the Earth cont. Publication retrieved on 10 Sept 2007 from http//inkido. indiana. edu/a100/earthmoon7. hypertext mark-up language