It's getting hotter and hotter online.

Does Zhang Heng's seismograph really exist in history? Can it predict or monitor earthquakes? Is the seismograph we saw by Zhang Heng real or fake?

In fact, every year or so, similar discussions will always "make a comeback" on the Internet. In order to find out the historical source of "Zhang Heng Seismograph", supporters look for historical basis from different angles-the records in the Book of the Later Han Dynasty are considered as irrefutable evidence; Opponents firmly believe that the seismograph is a historical fabrication and cannot stand scrutiny.

Is Zhang Heng's seismograph true or not?

"Zhang Hengchuan in the Later Han Dynasty" records: "When you taste the opportunity of Yi Long, you don't feel it moving. Scholars in the capital accused it of lacking signs. A few days later, there was an earthquake in western Gansu, and they all took wonderful pictures. " The brief record in the history books later evolved into a widely circulated story-in the Eastern Han Dynasty, earthquake disasters were frequent. Through repeated experiments and explorations, Tai Shigong made Zhang Heng make a seismograph in A.D. 132, and successfully monitored many earthquakes, including the Longxi earthquake.

More than a thousand years ago, did Zhang Heng have the ability to build such a high-tech seismograph? Is it true to test the magical "Longxi earthquake" of the seismograph? Scholars from all sides have been controversial.

Sceptics think that Zhang Heng's seismograph is impossible to realize in principle, and some even think that it doesn't exist at all. Among them, Austrian Lei Libai is the most acute. He once wrote Zhang Heng: Religion and Science, and thought that China people's affection for Zhang Heng's seismograph was a kind of religious worship. In his view, the loss of the seismograph means that it is unscientific and impractical, and there is no reason not to lose it.

But more scholars believe that seismographs really existed, because "if you don't believe in clearly recorded history, all history will become nothingness".

Dr. Chen Tianjia, a teacher at the School of Humanities, Chinese Academy of Sciences, believes that Zhang Heng's seismograph exists and has the function of earthquake monitoring, but the repair work has not been completed yet.

What does a seismograph look like? What you saw was fake.

The intuitive impression of Zhang Heng's seismograph mostly comes from a picture in the textbook, which looks like a wine bottle with a dragon ball and a toad outside. In fact, this seismograph, which frequently appears in history textbooks and science and technology museums, is only a restoration model made by an old man named Wang Zhenduo in the 1950s. Because of the principle error, this restoration model can't really monitor the earthquake.

"Made of pure copper, it is eight feet in diameter, covered with bumps, shaped like a wine bottle, decorated with the shapes of seals, turtles, birds and animals. There is a column in capital ... "is a complete description of the seismograph in the Book of the Later Han Dynasty. All subsequent studies are based on this passage. Over the years, the academic circles have made an in-depth analysis of this record word by word, and only the understanding of "single column" has produced many kinds of "column", "inverted pendulum" and "suspended pendulum".

Chen Tianjia said that Zhang Heng's seismograph has been studied and repaired. However, due to the simple records in ancient China, the restoration work of later generations faces many challenges, and people also have many arguments about seismographs.

Recovery work is in progress, and 100% recovery cannot be achieved.

/kloc-what was the seismograph like 0/800 years ago? Not only are we curious, but our predecessors are also curious. The research and repair of seismograph began more than 100 years ago.

Milne, the founder of modern seismology and an Englishman, once did experiments with columns. However, in the experiment, the column will fall in all directions after shaking slightly, and it is impossible to indicate the direction of the earthquake. Later, he put forward the theory of "hanging pendulum". 1936, Wang Zhenduo, a history major in yenching university Graduate School, drew the first set of drawings of his restored seismograph model, and inferred from the working principle of the "upright pole" model in 195 1 year, made an exhibition model of Zhang Heng's seismograph and displayed it in the China History Museum. This model is widely circulated, but its authenticity and working principle have been questioned by scientists at home and abroad.

At the beginning of the 20th century, Feng Rui, a researcher at the Institute of Geophysics, and his research team did a lot of research and made a restoration model. However, the academic community also questioned this version of the model, arguing that its key points could not be closely related to the original literature. Chen Tianjia said that it is difficult to recover 100%, and it is really impossible to achieve full recovery at present.

In recent years, although the public's attention to the seismograph has not diminished, the academic community's attention to Zhang Heng's seismograph has weakened. The academic circles are not optimistic about "restoring seismographs to realize earthquake monitoring and prediction" that many netizens expect. In Chen Tianjia's view, the scientific research and restoration of Zhang Heng's seismograph is of greater historical significance than practical significance.