How Islamic astronomers changed China’s view of the stars

Centuries ago, Middle Eastern scientists influenced the way the Chinese saw the universe

Dating back almost 600 years, Beijing's Ancient Observatory is laden with old astronomical instruments. Courtesy Ronan O'Connell
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Near a forest of skyscrapers in downtown Beijing, four dragons have combined their strength to lift a replica of the solar system. In Chinese culture, no image is more auspicious than the dragon, which symbolises power, wealth and fortune. It is fitting, then, that those mythical creatures are depicted by this steel statue as trying to come to grips with the universe. Because this is just what the Chinese have been attempting to do for thousands of years.

This metallic model, called an armillary sphere, is one of many historic scientific instruments scattered through the grounds of the 579-year-old Beijing Ancient Observatory. An offbeat tourist attraction, the huge building looks like a weathered fortress and is brimming with astronomical relics, some of which were influenced by Islamic science, particularly during the Islamic Golden Age in the 1200s. Back then, brilliant Muslim mathematicians were brought to Beijing to share their knowledge and alter how China analysed the universe.

 An armillary sphere decorated by Chinese dragons on the grounds of the former observatory. Courtesy Ronan O'Connell

A sliver of green lies about 700 metres south of the observatory, largely hidden behind high-rise buildings. This is the Ming Dynasty City Wall Relics Park. Within this small public space are some of the finest remains of the fortifications that surrounded and protected Beijing during China’s Ming Dynasty (1368-1644). But it was during the previous Yuan Dynasty (1279-1368) that Islamic astronomers first made their mark in China. By that stage, the country had long been paying close attention to the sky.

The small but informative museum inside this observatory complex displays Chinese ceramics up to 5,000 years old, which are embellished by images of the Sun and the stars. Elsewhere, solar eclipses are mentioned in Chinese texts dating back 2,700 years.

Not long after that, the ancient Greeks made a discovery that changed human perception of the physical world. In the 6th century BC, Greek academics produced evidence that our apparently flat planet was in fact spherical. They did this by highlighting how the sky’s appearance varied depending on the location from which it was viewed, and by documenting the curved shadows cast on to the Moon by the Earth during lunar eclipses.

Beijing's Ancient Observatory is one of the best preserved sites of astronomical study in Asia. Courtesy Ronan O'Connell

What these Greek scientists did not know was that some of those stars they monitored so closely would eventually explode. Like a magnificent piece of abstract art, the dark canvas of space would be decorated by an eruption of light and colour marking the end of that star’s long life. This was a supernova.

Stars had been dying in this spectacular fashion for millions of years before a human ever took note. It was in China in the year 185 that a supernova was first documented, as highlighted by the observatory's museum. Now known by scientists as SN 185, this exploding star created a unique pattern that remained visible to humans in the night sky for eight months. One Chinese observer recorded this unusual event, which was then included in the important Chinese historical text The Book of the Later Han.

The Chinese were not only intrigued by the mysteries of the stars, or beguiled by their beauty. They were also wary of their wrath. Chinese historical records, some dating back more than 2,000 years, make repeated mention of falling stars. These accounts are now widely believed to describe large meteors striking the Earth.

Official texts even detail deadly meteors, including a fallen star that supposedly killed 10 people after smashing into a rebel base in China in the year 616. While scientists who’ve investigated this account have been unable to prove its veracity, such stories fed into ancient China’s fear of, and fascination with, the sky.

By the 1200s, China had a strong grasp of how the solar system operated. But it was not satisfied with that. During the Yuan Dynasty, its Emperor Kublai Khan recruited outstanding minds from all over the world. One of those foreign geniuses was Marco Polo, the Italian explorer who spent about 20 years serving as an ambassador for Khan.

In 1271, the same year that Polo first set off for China, Khan built an observatory in Beijing to be used specifically by Middle Eastern scientists. Islamic astronomers were then widely considered to be among the most advanced in the world. So the Yuan Dynasty gave them their own sophisticated facility, well equipped with Arabic texts and instruments.

 A statue of a Belgian missionary who designeed astronomical instruments at the observatory in the 1600s. Courtesy Ronan O'Connell

In command of the more than 30 staff at Beijing’s Islamic observatory was Jamal Al Din, a renowned Persian astronomer. He oversaw the creation of a handbook that explained the methods of Islamic astronomy. This and other works by the Islamic scientists were later translated into the Chinese languages and studied by Beijing’s elite astronomers.

Particularly during the Ming Dynasty, Chinese astronomers began to double-check their own measurements and findings against those of Islamic astronomy, to try to hone this science. Accuracy was crucial. These comparisons with Islamic astronomy were particularly useful to the Chinese in predicting solar and lunar eclipses.

Equally influential was the precise Islamic method for calculating the latitudes of the Moon and the so-called “Five Planets”: Mercury, Mars, Jupiter, Saturn and Venus. Those planets were especially important to the Chinese, who viewed them as representing the five elements of life – water, fire, wood, earth and metal, respectively.

China is believed to have been studying the sky for up to 5,000 years. Courtesy Ronan O'Connell

So great was China’s respect for Islamic astronomy that the observatory continued to operate in Beijing for almost 400 years. Its highly respected scientists influenced their Chinese counterparts, who worked at the Beijing Ancient Observatory, which was opened in 1442.

This historic complex has not been used for scientific purposes since 1929. Yet in recent decades it has again become a centre for the international exchange of information and ideas. Not as a research facility, but rather as one of Beijing’s most unusual tourist sites, which attracts travellers who, like the ancient Chinese, are keen to better understand the stars.