Cosmic Quest

Revolution Number Two: Dethroning the Earth

Copernicus (above) got his hands on some of the ancient records of predicted planetary positions; and – lo and behold! – the planets weren’t where they should be. He realised that things would be much better if it was assumed that the Earth travelled around the Sun, rather then vice-versa.

The scene was now set for astronomy to change forever. In 1609, Galileo Galilei turned his ‘optick tube’- the newly-invented telescope – towards the sky. Galileo made bold of his findings: that the Earth circled the Sun, and that the heavenly bodies were not perfect. The Moon was pocked with craters; and the Sun was spotty.

This was not good news for the Church authorities, who believed in the supremacy of a central Earth, and the purity of the Sun, Moon and planets. For his heresy, Galileo was placed under house arrest until he died. But his findings in astronomy and mechanics were to inspire a young Englishman, Isaac Newton, who was born in the year that Galileo died.

With his formidable mathematical brain, Newton worked out why bodies in space moved in the way they do: there was a new force to be reckoned with – gravity. At last, astronomers could calculate what was going on in the Universe, rather than just predict the future by what had happened in the past.

Now - armed with the power of the telescope, Newton’s laws, and dramatic strides in technology – astronomy was poised to surge forward. William Herschel doubled the size of the Solar System in 1781 when he discovered the planet Uranus; astronomers were at last able to measure distances to the stars; and – thanks to the labours of the German scientists Joseph von Fraunhofer, Robert Bunsen and Gustav Kirchhoff – they were able to ascertain their chemical make-up. Photography was a glorious spin-off of the new technology – it allowed observers to record their findings in perpetuity.

As the twentieth century hoved into view, the astronomical community was getting to grips with the structure of the Universe. Was our Galaxy all that existed? Or was it just one of billions? The latter proved to be the case; and – in one of the greatest discoveries of the last century, made by Edwin Hubble – our Universe is expanding.

And just over sixty years ago, the latest revolution in astronomy took off: one as great as that which happened in the era of Copernicus and Galileo.

Astronomers discover the Universe is not just beautiful - it is deadly... Read on to find out more....