Since ancient times, people have been trying to make sense of celestial bodies and phenomena. Early civilizations attempted to track the motions of stars, planets, and other objects, mapping their place in the sky. This laid the groundwork for the study of astronomy today, but advancements in fields such as physics, chemistry, and mathematics have led to exciting new astronomical discoveries in recent decades. This volume examines some of the discoveries that have impacted the field of astronomy--both impactful new innovations and historical findings that have changed the trajectory of research in the field. It also offers readers a better understanding of some of the methods used for making these discoveries.