|
Young World
WORLD OF SCIENCE
Measuring Earth
DR. T. V. PADMA
|
How would you measure the circumference of the Earth?
|
Have you ever wondered how large our world is? One of the earliest attempts to measure the circumference of the Earth was made by Eratosthenes, a Greek mathematician, about 2,300 years ago. The Earth is obviously too large for anyone to measure using a measuring tape or piece of string. So how does one measure the circumference?
Eratosthenes did this by determining the angle to the sun from two different places. Then, he measured the distance between the two places. Using these measurements, and his advanced knowledge of geometry and mathematics, he estimated that the distance around the globe was between 28,000 and 29,000 miles (45,000 to 47,000 km).
That was awfully close to the correct value of about 24,860 miles (40,008) km.
Islamic scholars discovered the manuscript in which Eratosthenes had described
his experiment and they preserved it.
House of Wisdom
Around 815, one Islamic ruler built a huge learning centre in Baghdad where he preserved this and other manuscripts. He called this centre the Bait al-Hikmah or the House of Wisdom. He was so curious about the idea of measuring the Earth’s circumference that he asked the members of the House of Wisdom to repeat the experiment. So they measured the distance between two cities and the angle of the sun from each city, and then recalculated the circumference of Earth. They also came close to the correct estimate, though not as close as Eratosthenes — they estimated 20,400 miles (32,830 km).
Islamic centres of learning, such as the House of Wisdom, preserved many of the scientific texts collected from across the globe. Muslim scholars were not merely custodians of previously gained knowledge, however — they also played an active role in increasing our scientific and mathematical knowledge by adding creative contributions of their own.
Printer friendly
page
Send this article to Friends by
E-Mail
Young World
|
