 Hello, I'm Brian Schmidt. And I'm Paul Francis. In this course, we'd like to share with you one of the greatest revolutions of modern astrophysics, the discovery of exoplanets, planets orbiting other stars. And how these discoveries are changing how we understand how solar systems like our own form. Twenty years ago, we knew about precisely one planetary system. Our own. There were countless trillions of other stars out there, but we had no idea if they had planets orbiting them or not. To me, things are very different. We know of more than a thousand planets beyond our own solar system. The universe is literally teeming with planets. And some of these planets are very strange indeed. Hot Jupiter-like systems which are literally skimming their stars' surfaces. Cold and lonely, free-floating planets drifting far away in the deepness of space. Diamond planets and planets with rain made of glass. Super-Earths and even planets orbiting neutron stars that really shouldn't exist. Each of these discoveries are helping us shape our understanding of how solar systems like our own form. This is one of four courses that together make up the Australian National University's first year astrophysics unit. The other three courses include an introductory course to the greatest mysteries of the universe, a course in the violent universe, and finally a course in cosmology. You can take these courses individually or combine all four to get a complete overview of modern astrophysics. To really get the most out of our courses, you need to have a solid understanding of high school level physics and maths. Hard day a week goes by without us opening our newspapers and discovering yet another exoplanet discovery. And we look forward to sharing the latest results with you.