The concept of 'missing mass' has a long, often-resisted history in astrophysics. Fritz Zwicky's initial observations in the 1930s were largely overlooked for decades, partly due to his abrasive personality and the nascent state of cosmological modeling. It wasn't until Vera Rubin's meticulous work on galaxy rotation curves in the 1970s that the evidence became undeniable and widely accepted, transforming 'missing mass' into 'dark matter.' Even then, it faced skepticism, with many astronomers initially preferring to explain the anomalies through unseen ordinary matter (like burnt-out stars or faint gas). The shift from skepticism to broad acceptance reflects a common pattern in science: persistent observational anomalies eventually force a paradigm shift. The development of sophisticated cosmological models and precise measurements of the Cosmic Microwave Background in the late 20th and early 21st centuries solidified dark matter's place as a fundamental component of the universe, demonstrating the scientific community's ability to adapt and revise its understanding in the face of overwhelming evidence.