University of Pennsylvania Astrophysics Group Seminar

Voids are among the largest features in the Universe, with typical size 15 h-1 Mpc in radius, and they have been known to exist for over twenty five years. However, they are very empty; typical densities are less than 10% of average. These two facts make them very difficult to observe and thus it is only in recent years that their properties have been examined in detail. I will give an overview of how we observe nothing, describe how voids can be found and present the latest results on voids detected in the Sloan Digital Sky Survey.