Coastline Paradox: Countless Correct Answers

Various agencies around the world measure coastline lengths.

Different agencies may measure the length of the coastline in the same area.

However, even in the same place, there are times when the records differ.

For example, the length of the coastline in Japan is announced as follows.

According to a Japanese institution, about 22,400 miles

According to the US CIA, about 18,000 miles

The data for both are very different.

Which is correct.

In fact, neither is wrong.

This is because the length of the coastline changes depending on the scale of the map used for measurement.

Suppose a person actually walks and measures the coastline.

To do this, you need to walk along the coastline where you want to measure the length with a certain stride.

At that time, the formula “step length x number of steps = length of coastline” is established.

However, when a child with a small stride walks to every corner of the beach, it will be longer than when an adult with a large stride walks quickly.

The problem is here.

There are countless small folds on the inner wall of the human small intestine.

These folds allow you to efficiently absorb nutrients from the digest.

When measuring the surface area inside the small intestine, the answer should be different if you measure all the folds and if you ignore them.

However, only one of them cannot be the correct answer.

This is also the case for coastlines, the answer depends on the scale.

The smaller the stride, the more detailed the measurement, and the longer the distance.

This is the reason why the measurement results in the United States and Japan are different.

Wolfram MathWorld: Coastline Paradox

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