Science Stories of the World's 5000 Years (Color Illustration Version)

Author: Wei Zhimin, Wang Yan
Publisher:
Publish Date: 2005-11-26
Features: This book aims to create a brand-new read on world scientific knowledge through an encyclopedic editing concept. It carefully selects nearly one hundred scientific stories, covering major scientific discoveries, technological inventions, and scientists that have had a significant impact on humanity. The book narrates the evolution of world science in a captivating way, blending knowledge with fun. A crystallization of 5,000 years of human wisdom, featuring over 100 scientific masters, more than 100 technological achievements, 150,000 vivid words, and over 300 exquisite illustrations, it takes you on a colorful journey through a dazzling world of science.
The early solar calendar
Among the various calendars that have been popular in the world, it includes the Chinese Shoushi calendar, ancient European calendars, ancient Greek calendars, and ancient Babylonian calendars. The ancient Chinese calendar determined the calendar based on the phases of the moon and its orbital period; the ancient European calendar was based on changes in celestial phenomena; the ancient Greek calendar was also based on changes in celestial phenomena; and the ancient Babylonian calendar was based on celestial phenomena and the rise and fall of the Tigris and Euphrates rivers. Among these calendars, the shortest year had 354 days, and the longest had 384 days.
When it comes to Egypt, most people immediately think of the pyramids, and that’s correct! The pyramids have become a symbol of modern Egypt, but as one of the four ancient civilizations, Egypt’s other significant achievements include the solar calendar. The ancient Egyptian solar calendar is the earliest calendar in human history, appearing around 4,000 BCE, closely related to the regular flooding of the Nile River. In a sense, it can even be said that the Nile River’s regular flooding gave rise to the solar calendar, so it’s necessary to provide some background on the Nile River.
The Nile River refers to the main course of the two rivers—the Blue Nile and the White Nile—after they merge in Khartoum, the capital of Sudan. It is 6,700 kilometers long, making it the longest river in the world, flowing through Tanzania, Rwanda, Uganda, Kenya, Ethiopia, Sudan, and Egypt, among other countries, before finally emptying into the Mediterranean Sea. The Nile River dominates the fate of the countries it flows through, and without its nourishment, the civilization in these regions would perish. However, due to the slow flow of the Nile River and the continuous deposition of silt, the riverbed has been steadily rising, leading to frequent floods. But when the water recedes, it leaves behind vast fertile land. Therefore, the ancient Egyptians needed to find patterns to benefit from and avoid the dangers of these floods.
After long-term observations, the ancient Egyptians gradually discovered the of the Nile’s flooding. When the river began to flood, the bright star Sirius was exactly on the horizon in the morning. This astronomical phenomenon is known as "conjunction with the sun," meaning it rises at the same time as the sun. Thus, this day was set as the beginning of the year. Unfortunately, the cycle of Sirius’s conjunction with the sun was not discovered quickly, but the wise ancient Egyptians did not give up. After generations of relentless effort, they finally discovered that the day of Sirius’s conjunction with the sun was exactly one month apart from the day 120 years later. By the 1461st year, the day of conjunction with the sun once again became the beginning of the year. Therefore, the ancient Egyptians set a 1460-year cycle as the Sothis Cycle (because, in their mythology, Sirius was called the "Dog Star").
A simple comparison between the ancient Egyptian solar calendar and the current Gregorian calendar reveals its scientific nature: the year had 365 days, which were divided into 12 months of 30 days each, with the remaining 5 days set aside as religious holidays, similar to the 5-day traditional Chinese Spring Festival. This was only 0.25 days shorter than a precise tropical year (365.25 days). After 120 years, it was 30 days shorter, and after 1460 years, it was 365 days shorter, bringing it close to a full year. This formed a complete cycle. Such a sophisticated calendar embodies the wisdom of countless ancient Egyptians.
In ancient Egypt, people spent a lot of time observing celestial phenomena, especially the position of Sirius, with meticulous attention. They discovered that at fixed times, Sirius would disappear from the sky and would rise again from the eastern horizon when the sun reappeared at the same position, marking a year. At the same time, the ancient Egyptians set the day when Sirius rose before the sun as the New Year. The solar calendar created by the ancient Egyptians had a profound impact on agricultural production in the Nile River Basin, which was also a key reason why ancient Egypt became one of the four ancient civilizations of the world.
With such a relatively complete calendar as a guide, the ancient Egyptians were able to accurately predict the rise and fall of the Nile River’s water levels, arrange farming schedules wisely, and achieve abundant harvests year after year, thus securing a stable source of food and clothing. On this material basis, ancient Egypt was able to create even more brilliant achievements in fields such as religion, architecture, and medicine.