A few weeks ago, I posted about the Yale astrophysics class to which I was listening. I haven't had time recently because I have been studying for exams, but I did read a New York Times article this afternoon in which I realized I actually vaguely understood the science behind the discovery.
I am going to make an attempt at explaining this from memory, although science people please correct me if I explain this wrong. So in general, astronomers do not detect planets by seeing them. Instead, they measure electromagnetic waves and use Doppler shifts in order to determine the size, speed, and distance of stars an the planets that orbit them. In certain cases, the planets are oriented so that they pass directly between the telescope monitoring them and the star they orbit. In these cases, there are significant dips in the electromagnetic radiation whenever the planet crosses in front of the star and it allows scientists to determine that the planet is there and stuff about it with a great degree of accuracy. It's pretty cool. This is especially fabulous because the planet is actually circling two stars, hence the planet has been named Tatooine. Unfortunately, this planet's alignment is changing due to it's orbit and it will not pass directly in front of the star any longer.