Geometry of the Earth Long before Columbus, a Greek scholar names Eratosthenes (274-194BC) calculated the circumference of Earth by making some simple observations about shadows at noon and applying some insights from geometry. The size of Earth has been estimated and measured many time since then. The French Academy of Sciences tried to make an accurate measurement in the late 1700s in order to create a new unit of measure, the meter. They proposed to define the meter as one ten-millionth of the distance from the North Pole to the equator. Today we can measure Earth's circumference very accurately using data from satellites and making calculations on computers. The circumference at the equator is 24,901. 55 miles. Earth is not a perfect sphere, however, because its rotation c
Questions and Answers
How many centuries before the French Academy of Sciences measured the circumference of Earth did Eratosthenes live?
How much greater is the circumference of Earth at the equator than the circumference at the poles?
About 20 miles
About 40 miles
About 80 miles
About 200 miles
Earth is divided into 24 time zones. About how wide is each time zone at the equator?
Which is the best estimate of the diamter of Earth from pole to pole?
A geostationary satellite move in an orbit 22,300 miles above the equator. The satellite moves at a rate such that it stays at the same point about the Earth as Earth rotates on its axis. What is the appoximate speed of the satellite?