Chen Zi, a character in the book, told Fang Rong that if an 8-foot-long (then 1 ft, about 23 cm) hollow bamboo pole was aimed at the sun, the sun was observed at one end of the bamboo pole, and the middle hole (the other end) of the bamboo pole was covered, so that the distance from the sun to the ground observation point/sun diameter = bamboo pole length/aperture = 80: 1 was obtained.
In addition, an 8-foot-long bamboo pole was erected in an open space in Zhouwangcheng as a "watch" (also called "mustache"); It can be observed that the sun shadow of the watch is the shortest at noon from summer to Sunday every year, which is1'6 "; In the direction due south (north), every 1000 miles, the shadow is short 1 inch (long). So, at noon on the day when the shadow of the table was 6 feet long, there was no shadow 60 thousand miles south of the table; Using Pythagorean theorem and proportional method, it is calculated that the distance from the sun to the shadowless place on the ground at that time is 80000 Li, and the distance from the sun to the observation point of Wangcheng is 10 Li. Further calculation shows that the diameter of the sun is 1250 Li.
Sunrise map?
Now we know that the average distance from the sun to the earth is 6.5438+0.496 million kilometers and the diameter of the sun is 6.5438+0.39 million kilometers, so the ratio of the distance from the sun to the earth to the diameter of the sun is about 654.38+0.007: 654.38+0.
Book Week Fast Shu Jing?
3000 years ago, the ancient people's calculations were quite different from the actual observed values in modern times, mainly because they thought the earth was flat, although they used correct mathematical principles. However, the error of the ratio of the distance between the sun and the earth and the diameter of the sun measured by them is not too big.