The Dunhuang star map of 700 AD.
Credit: wikimedia
Imperial China had an uninterrupted dynastic history of more than 2,000 years. Many things contributed to this remarkable longevity – one of them was its astronomers.
When a new emperor came to power, one of his first priorities was the creation of a new calendar. Millions of peasants across the vast central kingdom relied on the Imperial calendar to know the best times to sow, when to till and when to harvest.
Food production – and the efficient management of the kingdom – was totally reliant on this. But all calendars drift over time, so they need updating in order to match the celestial movements.
The calendar was also essential for the emperor to maintain his 'mandate of heaven'. In Imperial China, man's organisation of time was seen as a reflection of the natural cosmic order; the stars, the Sun, the Moon, the Earth and the activities of society, needed to be in harmony.
So it was crucial for a new emperor to have his court astronomers restore to the calendar its 'proper balance' with the cosmos. It was an act of state and an essential exercise of Imperial power.
Astronomy as a professional discipline in China even predates Imperial China, and may have begun as far back as 1300 BC. But astronomy itself is one of the oldest natural sciences, with origins in the religious, mythological and astrological practices of pre-history.
Our long fascination with the stars can be seen in the antiquity of structures such as Stonehenge, first built around 3100 BC, and Egypt's first great pyramid in Saqqara, built by the high priest and astronomer Imhotep in 2630 BC. Celestial navigation allowed sailors cross the featureless oceans of the world without having to rely on 'dead reckoning' to strike land, saving lives at sea and dramatically expanding the range and spread of civilisation.
But it took the invention of the telescope before astronomy was able to blossom beyond the calendar business into a modern science. Instrumental in this was Galileo Galilei, a 16th century Italian mathematician who – 400 years ago this year – pointed his hand-made telescope to the heavens and ushered in a major new phase in the scientific revolution.
He has been called the father of modern astronomy, modern physics and even modern science, according to the celebrated British astrophysicist Stephen Hawking: "Galileo, perhaps more than any other single person, was responsible for the birth of modern science."
