Extrasolar planets, or exoplanets, are planets that orbit stars other than our Sun. They are of great interest to the scientific community for many reasons, but are very hard to detect. Planets are extremely faint light sources, especially when compared to their nearby host stars, so many different methods have been created and refined in order to keep discovering new exoplanets. One of the most successful methods currently is transit photometry.
Transit photometry is focused around finding planets that pass directly between their host star and us during their orbit. As the planet eclipses its star, the starlight is very slightly dimmed. If this dimming is observed periodically, it is possible that it is caused by a transiting exoplanet. The data from the star can be graphed into what is called a light curve, shown here to the left. If it is indeed caused by an exoplanet, the depth of the change in brightness can also be used to determine the size of the planet.
Vanderbilt University is actually part of a team called KELT (Kilodegree Extremely Little Telescope), a project conducting a sky survey for transiting exoplanets around bright stars. They are already responsible for the discovery of multiple exoplanets, and hopefully they will find many more!