The concept of unseen matter has a rich history, dating back to the 1930s when Swiss astronomer Fritz Zwicky first observed 'missing mass' in the Coma Cluster. He noted that galaxies within the cluster were moving too fast to be gravitationally bound by the visible matter, suggesting the presence of 'dunkle Materie' (dark matter). However, his findings were largely dismissed for decades. It wasn't until the 1970s, with Vera Rubin's meticulous observations of galactic rotation curves, that the evidence became undeniable and widely accepted within the astronomical community. Since then, the dark matter hypothesis has evolved from a peculiar anomaly into a foundational pillar of modern cosmology. This historical journey underscores the often-slow and iterative nature of scientific discovery, where revolutionary ideas can take decades to gain traction and require cumulative evidence from diverse sources before fundamentally altering our understanding of the universe.