June 01, 2009

Article at Cosmos Magazine

OPINION | Mandate of Heaven

The Dunhuang star map, circa 700 AD

Astronomy and space exploration has made a critical contribution to society, not just in accelerating technology, but in giving us important clues to problems on Earth.

By Wilson da Silva

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.”

These days we take the fruits of astronomy for granted; some even ask why we spend so much money looking at the stars. And yet, astronomy brought us Newton’s laws of motion (which allow us to fly across continents and build bridges), global communications, weather forecasting and cyclone warnings, even the GPS navigation in your car. It gave birth to physics, which in turn gave us electricity, computers, the Internet.

Even the discovery of global warming has space research to thank: it was while trying to understand why Venus was so horribly hot that scientists realised too much carbon dioxide could create a runaway greenhouse effect.

Studies of Mars and its occasional planet-wide dust storms – which led to plunging temperatures on the surface – led scientists to the realisation that a decades-long ice age could be triggered on Earth by a nuclear exchange, the so-called ‘nuclear winter’ effect.

So astronomy – and the exploration of space – has made a critical contribution to society, not just in accelerating technology and giving us things like computers and mobile phones and the ability to build massive structures, but in giving us important clues to problems here on Earth.

Which is why the United Nations is celebrating 2009 as the International Year of Astronomy. And why we should celebrate the great advances we have made in exploration of space, from Galileo’s first tentative steps to the crowning of achievement 40 years ago of landing humans on the Moon, where they could stroll as if across a meadow here on Earth.

It is by stretching beyond the horizon that we push technology past its limits, learn something new about the universe, and get a whole new perspective on who we are and the place we call home: Earth.