Mountaintop blasted to build largest telescope

This week, 3000 metres up a Chilean mountain, scientists pressed the button to blow up half a million tonnes of rock. The mountain's called Cerro Armazones and the reason it was being blown up was to create the site for what will become the world's biggest most powerful optical telescope. With typical scientific understatement its known as the European Extremely Large Telescope or EELT. Isobel Hook an astrophysicist from Oxford University told Chris more about the project.