Almost two thousand years ago, during the Han dynastythe Chinese scholar ZHANG HENG He designed a device that, according to historical chronicles, could detect distant earthquakes and even point out his address. That invention, called HouFeng Didong Yiit was a mechanical gadget that had the dragon as the main actor. Now China is about to resurrect what a legend was believed.
A erased prodigy of time. We talk about a mechanical system (an ornate vessel surrounded by eight dragons with suspended bronze balls, oriented towards mouths of toads) that would have been able to register imperceptible earthquakes in Luoyang, the imperial capital, with a precision that “touched the divine”, according to THE BOOK OF THE Subsections.
However, its sudden disappearance of historical records and the impossibility of replicating it exactly led to its total elimination of the Chinese educational curriculum in 2017, relegating it to the field of legend. Today, a team led by Professor Xu Guodongfrom the Hebei Disaster Prevention Institute, seeks to recover not only its operation, but also Your place in history of science.
The rebirth of a prodigious machine. To the question: How the hell will they replicate it? The researchers They explain that from ancient literary fragments and principles of modern structural dynamics. Thus, Xu and his team have proposed a functional model of the earthquakescomposed of three key subsystems: structure of excitementtransmission and closure.
In the heart of the device he was A «Capital Pilar» that should not be interpreted as an unstable column, but as a pendulum -like arm (a kind of gigantic stick anchored to the ground) that amplified the seismic vibrations. With just 1 mm of displacement at the base, the tip of the pendulum moved up to five times more, activating a “L” levers system that released a ball in the mouth of the toad corresponding to the direction of the epicenter. A blocking mechanism prevented other dragons from reacting, thus respecting the Original description of «a dragon who speaks and seven that shut up.»
Mathematical Wisdom. Team simulations indicate that the system responded reliably to displacements just 0.5 mmwithout emitting false alarms. Although modern knowledge of propagation of seismic waves suggest that a single instrument cannot determine with total precision the direction of the epicenter, Xu argues that the Historical records coincide with optimal geological alignments.
As proof, appointment The Longxi earthquake From the year 138 AD, when the instrument would have detected a tremor 850 kilometers away, without feeling in Luoyang. The initial skepticism of the officials vanished when messengers on horseback confirmed The shaking days later. Even more revealing, he explains, is the jump in the frequency of earthquakes registered in the capital after the implementation of the artifact: in the previous 8 years they were only documented three local earthquakes; In the 58 years later, there were 23, in a region considered low seismicity.
Zhang HENG: astronomer and political victim. ZHANG HENG It was not any inventor. His appointment as a great imperial astrologer in 115 (a position equivalent to the director of a modern national observatory) and his creation of an armilar sphere Able to map the sky with precision, they prove their domain in mathematics, astronomy and mechanics. But his invention could have been politically uncomfortable.
In a context where natural disasters were interpreted as signals from heaven and threats to the mandate of the emperor, an instrument that «predicts» earthquakes could have been seen as subversive. Some scholars suggest that HENG’s abrupt retirement in 138 and his death the following year They were not casual. Xu duck that the loss of the original earthquakes (along with its technical diagrams) could be due to wars, political chaos or even the greed of powerful aristocratic families that would have hidden its existence.
Recovered legacy. In a gesture loaded with symbolism, xu He recalled that only two bronze objects have been defined in Chinese history: Nine cauldrons of the Xia dynasty and this earthquakes. Now, the objective is ambitious: rebuilding the instrument using only materials and technical Advanced knowledge reached in ancient China.
Beyond the material restoration, the project aspires to reinsert this jewel of engineering in the global narrative of science, as proof that humanity had already tried, long before satellites or artificial intelligence, unravel the Mysteries of the tremor From Earth.
Along the way, the Heng’s featerased for centuries of oblivion, it could be closer to recovering its place among the great milestones of human thought.
Image | KowlooneseSSPL
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