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Eratosthenes lived from ~ 276 BC - c. 195 BC. In the text In On the Circular Motions of the Celestial Bodies, Cleomedes credited him with having calculated the Earth's circumference around 240 BC, which would have made him around 36 years old at the time. For his part, Cleomedes wrote his text between between the mid-1st century BC and 400 AD (although probably between about 100 BC and 100 AD), so he was writing about a measurement that occurred hundreds of years in the past so we can only consider the 240 BC date as a reasonable estimate rather than established fact.
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When did Eratosthenes measure the circumference of the earth?
This was about 250 BC (c. 250BC) and is from the book:("Science For The Citizen - A social educator based on the social background of scientific discovery"by Lancelot Hogben (George Allen & Unwin 1944)Exactly the same information can also be found in:"Mathematics For The Million"also by Lancelot Hogben (originally printed by George Allen & Unwin in 1936, revised 1968, and reprinted in 1997 by Merlin Press)How he measured it:-He "compared the sun's altitude at two [locations], one 500 miles due south of the other, on the summer solstice. ... [T]he noon sun was mirrored in a deep well near Syene.....on the tropic of Cancer. The noon sun was therefore at the zenith. On the same day in Alexandria, 500 miles due north, the obelisk shadow showed that the sun was 7 1/2degrees from the zenith. Since the sun's rays are parallel, this means that the arc, or...the difference of latitude between Syene and Alexandria is approximately 7 1/2 degrees, and7 1/2 divided by 360 = 1/48 of the entire earth's circumference.[Since] the difference between Alexandria and Syene is 500 miles...the earth's circumference is about 48 x 500 = 24,000 miles.....The result agrees within 4% with modern determinations." [ Which is 24,902 miles.](Quote from 'Science for the Citizen', which I think would be safely out of copyright since it was written 64 (ie more than 50) years ago). It is also interesting to note that 2,250 years ago that Eratosthenes knew the earth was round and notflat, as is commonly arrogantly assumed by modern man of ancient(?) man, as did Tatius, Hipparchus, Poseidonius, and Strabo, who all likewise measured the circumference of the earth.
How did greek philosophers contribute to science?
Science in Ancient Greece was based on logical thinking and mathematics. It was also based on technology and everyday life. Ancient Greek philosophers proposed many theories to account for the from and origin of the Earth. Eratosthenes, a scientist of ancient Greece, made the first accurate measurement of the Earth's diameter. The ancient Greek philosophers were amazed by volcanoes and earthquakes. They made many attempts to explain them, but most of these attempts to explain these phenomena sound very strange to most people today. For example, Aristotle, speculated that earthquakes resulted from winds within the Earth caused by the Earth's own heat and heat from the sun. Volcanoes, he thought, marked the points at which these winds finally escaped from inside the Earth into the atmosphere.
Is it a fact that the Earth is round?
Yes, it is a fact that the Earth is round.
Is lithium considered a rare earth metal?
No, lithium is not considered a rare earth metal. It is a metal, but it is not classified as a rare earth element.
Does the sun revolve around the Earth?
No, the Earth revolves around the sun.
Who is calculate the circumference of earth?
Eratosthenes
Contribution of eratosthenes?
Eratosthenes had many contributions : he was the first person to calculate the circumference of the earth he invented latitude and longitude he was the first person to prove earth was round he was the first to calculate the tilt of Earth's axis
What describes how Eratosthenes discovered the approximate circumference of the earth?
Which of the following describes how Eratosthenes discovered the approximate circumference of the earth
When did euratosthenes calculate the circumference of the earth?
It is not known when, or even if, Euratosthenes did calculate the circumference of the earth. However, it is known that a very accurate estimate was obtained by Eratosthenes in the early years of the third century BC.
What did eratosthenes create?
He invented the system of longitude and latitude.He was too the first person who calculate the circumference of the Earth.
Who found circumference of earth?
Eratosthenes
Who invented area and circumference of a circle?
Actually, Eratosthenes of Cyrene (276? - 195? B.C.) was the first to calculate the Earth's circumference accurately. He is supposed to be the inventor.
What did Eratosthenes determine?
He postulated the circumference of the earth.
Greek scholar that estimated the earth's circumference?
Eratosthenes
Who was the greek mathematician who measured the circumference of the earth?
Eratosthenes
What place does Eratosthenes based the circumference of the earth?
rome
Does Eratosthenes determine Earth's diameter?
Yes, Eratosthenes estimated the Earth's diameter using the angle of the sun's rays at two different locations on the same day. By measuring the difference in the angles, he was able to calculate the Earth's circumference and thus its diameter.
