PART 1: The Universe is such a vast place that it is beyond the capability of mankind to understand it's true extent. The fact that there are on the order of 100 billion galaxies out there, each containing close to 100 billion stars is a mindboggling thought. Our star, the Sun, has 8 planets that orbit around it. This observation has naturally lead mankind to wonder how many other stars out there in the vast universe might also have planets orbiting around them. Although a relatively old question, it was not until 1995 (Mayor & Queloz 1995) that astronomers first discovered evidence of a new planet, orbiting a sun like star, outside of our solar system. Since then astronomers have discovered loads other planets. These planets outside our solar system, referred to as extra-solar planets or in short exoplanets, have been detected using many different methods. One of the main techniques, which will be covered in the next film, is the transit method.