2007-06-24 01:53:43 · 6 answers · asked by bougaine v 1 in Science & Mathematics ➔ Astronomy & Space
Erathostenes, who was mentioned by another poster first calculated the diameter of the Earth. He very cleverly noticed the angle of the sun at noon as it cast a shadow into a deep well in Alexandria .... and using simple geometry calculated the diameter. His answer was fairly close too.
2007-06-24 03:50:46 · answer #1 · answered by squeezie_1999 7 · 0⤊ 1⤋
A scientist (forgot which one is was) long ago traveled to the equator, put a stick in the ground, at certain days of the year (March21 and/or Sept 21) at noon the stick had no shadow. On other certain day (Dec 21 and or June21) the angle of the shadow was about 23.5 degrees.
He traveled to the Tropic of Cancer (~23.5 degrees about Equator), put his stick in the ground and measured the angle of the shadow on the above dates (different year). No shadow on June21, a 23.5 degree shadow on March 21 and Sept 21, then a 47.0 degree shadow on Dec 21.
He traveled to the Tropic of Capricorn (~23.5 degrees south of the equator) put his stick in the ground and measured the angle of the shadow on the above dates (another different year). No shadow on Dec 21, a 23.5 degree shadow on March 21 and Sept 21, then a 47.0 degree shadow on June 21.
He figured the distance he traveled from the Tropic of Cancer and Tropic of Capricorn. He used some Geometry (known back then) to figure the size of the earth. It was fairly close to what we know it is today.
2007-06-28 04:26:08 · answer #2 · answered by cpuguy_1 4 · 0⤊ 0⤋
As "N E" (answerer 2) has said, back in 240 BC, Eratosthenes got an answer correct to within about 15 per cent. Here is another web page describing his simple measurement and the theory behind it.
2007-06-24 16:12:01 · answer #3 · answered by bh8153 7 · 0⤊ 0⤋
True early people didn't know the size of the earth. Even in the age of Columbus, it was way underestimated. He thought he had sailed half way around the world to India when it was only across the Atlantic ocean.
2007-06-24 08:58:41 · answer #4 · answered by Joan H 6 · 1⤊ 2⤋
The circumference of the Earth was calculated first (as far as we know in history) by Erastothenes in 240 BC. Several nice descriptions are available on the web, including:
http://www.juliantrubin.com/bigten/eratosthenes.html
http://www.k12science.org/noonday/
2007-06-24 09:05:10 · answer #5 · answered by N E 7 · 1⤊ 0⤋
measure the size of ur mum and divide by 10000.
2007-06-24 09:05:32 · answer #6 · answered by jason6x6x6 3 · 0⤊ 2⤋