You might be interested to know that the circumference of the Earth is different depending on how you measure it. But if you measure it from pole to pole, you get 40, km. The Earth is a flattened sphere, and so the distance around the equator is further than the circumference around the poles. Want some comparison? The circumference of the Moon is 10, km, and the circumference of Jupiter is , km.
On simplifying, He arrived at the estimated value of 2,50, stadia, which is approximately equal to 28, miles. This estimated value is close to the actual value of 24, miles.
Method 2: We can also find out the circumference of the earth by using the direct formula for the circumference.
Since Earth is not a perfect sphere but an oblate spheroid, i. Hence, the circumference of the earth will be different for both the cases mentioned above. Example 1: If the diameter of the planet Mercury is 3, miles, what is the circumference of Mercury? Example 2: It is given that the diameter of the sun is , miles, find the circumference of the sun.
Circumference is defined as the length of the boundary of a circle. It can also be described as the arc length around a circle. Radius is defined as the distance between the center of the circle to the circumference of the circle.
Diameter is the line segment that passes through the center of a circle, and two of its endpoints lie on the circumference of the circle. The circumference of the Earth is the distance measured around it. The circumference of the Earth measured around the Equator is approximtely 24, By knowing the Equatorial diameter or the polar diameter of the Earth, the circumference can be found.
T he circumference of the Earth around the equator is approximately 24, miles. As the shape of the earth is an oblate spheroid, the diameter is different at the equator and at the poles.
Since the diameter at the equator is greater than the diameter at the poles, hence, the circumference of the great circle at the equator is the greatest. In the age of modern technology this may seem like an easy question for scientists to answer with tools such as satellites and GPS—and it would be even easier for you to look up the answer online.
It might seem like it would be impossible for you to measure the circumference of our planet using only a meterstick. He used a little knowledge about geometry! At the time Eratosthenes was in the city of Alexandria in Egypt. This meant the sun had to be directly overhead. Another way to think about this is that perfectly vertical objects would cast no shadow.
On that same day in Alexandria a vertical object did cast a shadow. You will need to do the test near the fall or spring equinoxes, when the sun is directly overhead at Earth's equator. There is a geometric rule about the angles formed by a line that intersects two parallel lines. Eratosthenes assumed the sun was far enough away from our planet that its rays were effectively parallel when they arrived at Earth.
It is much easier to visualize with a picture. Observations and results In B. Today we know our planet's circumference is roughly 40, kilometers 24, miles. Not bad for a more than 2,year-old estimate made with no modern technology! Depending on the error in your measurements—such as the exact day and time you did the test, how accurately you were able to measure the angle or length of the shadow and how accurately you measured the distance between your city and the equator—you should be able to calculate a value fairly close to 40, kilometers within a few hundred or maybe a few thousand.
All without leaving your own backyard! This activity brought to you in partnership with Science Buddies. Follow him on Twitter BenFinio. Already a subscriber? Sign in. Thanks for reading Scientific American.
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