As we all know, the armillary sphere made by Zhang Heng is a performance instrument for demonstrating the earth's orbit. This shape is like a sphere. Because Zhang Heng advocated the armillary sphere, it was called the armillary sphere. According to ancient records, the armillary sphere made by Zhang Heng is the same as the current one. The armillary sphere, the equator and the ecliptic are marked with 24 solar terms. The armillary sphere includes the armillary sphere and the armillary sphere. The armillary sphere consists of a large sphere with an equator, an ecliptic, stars, a stable circle, and an apparent circle. The interior of the armillary sphere is expected to be able to measure stars at dawn, dusk, the celestial equator and midnight.
Restored map of the armillary sphere
The armillary sphere has a rotatable polar axis at its north and south poles. The horizontal ring in the middle of the spherical perimeter represents the horizon. There is a horizontal double circle supporting the North Pole and South Pole axes. The meridian is in the middle of the two circles and the ground can be observed. When a planet rotates, the stars above the horizon are stars, the stars just reaching the meridian are stars, and the stars below the horizon are stars. Some stars in the celestial sphere do not set as they rotate in Earth's flat ring. This part is centered on the North Pole and has the latitude of the radius of a small circle. In ancient times, it was called the internal ruler. At the same time, Antarctica is the center, and the latitude of the small circle radius is the outer standard. The sky within the outer limits never rises above the horizon.
The armillary sphere has the sun, moon, five stars and seven celestial bodies. It rises and falls simultaneously with the armillary sphere and operates throughout the day. Of course, replicating so many complex movements is beyond the reach of ancient level technology, so they are usually attachments attached to the sphere that can be moved by hand. These actions can make the sun, moon and five stars move like the real sun.
Writing this, I can’t help but think that the armillary sphere was so cleverly and accurately conceived, and I wonder how much effort Zhang Heng put into it.
How many dragons does Zhang Heng’s seismometer have?
Zhang Heng was a scientist, astronomer and philosopher during the Eastern Han Dynasty in China. He was well versed in astronomy and calendars. Based on previous research, he invented the world's first hydraulic rotating armillary sphere and seismograph for measuring earthquakes.
Seismometer
Zhang Heng is one of the main representatives of the armillary sphere school. He improved the armillary sphere by using a gear system to connect it to the chronometer cauldron so that we could effectively measure the position of the star catalog from an indoor perspective.
The seismograph invented by Zhang Heng was invented in the first year of Yuanjia, that is, 132 AD. It is said that this was his great contribution during the reign of Tashshi. As you can see from the picture, the seismometer is made of copper. From the outside, it looks like a wine bottle. In the middle of it is a capital pillar, also known as the swinging pendulum. Around the capital column, there are eight directional machines, while eight bronze dragons are cast outside.
The eight bronze dragons outside the seismograph are arranged in a systematic and scientific manner. They are arranged in eight directions. Looking clockwise, they are north, northeast, east, southeast, south, southwest, west, and northwest. They are connected to the inside of the seismometer and are not independent. Each dragon has a bronze ball in its mouth. The copper coin moved in their direction and fell into the mouth of the copper toad below. The direction of an earthquake can be determined by the sound. In other words, during an earthquake, the "beads" are poking the small ball, and the small ball collides with the organ that controls the gap, thereby opening the gap.
From this point of view, the seismograph invented by Zhang Heng has eight dragons. These eight dragons not only establish a very clever connection between internal and external structures, but also allow for more accurate predictions of earthquakes. Zhang Heng's creations shocked ancient and modern times and promoted the development of science.
Principle of Zhang Heng’s seismograph
Zhang Hengsheng was born in the Eastern Han Dynasty. According to records, there have been no earthquakes for 20 consecutive years, and earthquake disasters are raging. It can be imagined how much suffering the court and the people suffered at that time. It can be said that the people did not have enough money to live a serious New Year. Zhang Heng was deeply troubled by a surname. After years of experiments and research, he successfully produced Zhang Heng's seismometer, which is made of pure copper and has a diameter of 2.7 meters. It looks like a wine bottle with a capital cylinder inside. The remaining eight dragons are exactly the same as the eight toads. Before or during an earthquake, there are always different fluctuations than usual, and different sound waves propagate at different times. Zhang Heng's seismometer can receive this kind of fluctuation earlier than others, thereby triggering the inner hanging column, causing the copper ball to fall into the mouth of the toad tree stump, making a sound to alert people.
The most famous achievement of Zhang Heng's seismograph is the monitoring of the Longxi earthquake. Although the people in the capital haven't felt it yet, the copper beads of Zhang Heng's seismograph have fallen off. This instrument plays a role in natural disaster monitoring for the first time. This moment is not only the glory of Zhang Heng, but also the glory of all mankind. From Zhang Heng's poems, we can also feel his pride in this glorious moment and his helplessness at the changes in the current situation.
Due to various reasons, Zhang Heng’s seismometer did not retain the actual object. Relevant records can be traced back to historical materials and contain more than 200 words. The scholar used these 200 words to make a complete cocoon and simulated the repair of Zhang Heng's seismograph. Although history cannot be completely restored, humankind's pursuit of scientific truth will never stop.