Kathy Sykes meets the designer of the world's largest telescopes. Chris Riley visits New York to see a two-mile long machine that re-creates the Big Bang. Plus a look at asteroids, the earliest relics of our Solar System. They could easily obliterate all life on our planet, but what can we, here on Earth, do about it? Also, we meet the first British astronomer in over two hundred years to find a new planet.