Stefan Grebe studied physics at Siegen University in Germany. During his final year he worked for 6 months as a guest scientist at the Instituto Baleseiro in San Carlos de Bariloche, Argentina. During his master and his PhD research at Radboud University Nijmegen he studied experimental questions about cosmic rays. Stefan analyzed large data sets from the Pierre Auger Observatory and helped to develop a new technology to measure the highest energetic particles in the universe. Since 2014 he is working as a researcher at Significance.