Physics education research explores the interplay between the instructor, the students, the curriculum, and the setting in which teaching and learning of physics takes place. The aim is to measure and understand what is happening, how it is happening, and why it happens in that particular way. I will highlight the tools and approaches available to start tackling these questions, and zoom in on several aspects of my study to unpack and understand faculty pedagogical and curricular thinking in an introductory astronomy course. The second, and equally important, role of physics education research is as a resource for the physics community. I will outline what physics education research can and cannot do for matters related to the teaching and learning of physics at the college level. Several avenues for future research will also be discussed.