In this captivating episode of Science Deep Dive, we journey into the mysterious realm of dark matter—the invisible giant that constitutes about 85% of our universe's mass. Picture this: when you flick on the lights, you can only see a fraction of the space around you. In the cosmos, the same holds true; the stars, galaxies, and planets we can observe represent just 5% of what exists. We delve into the historical backdrop of dark matter, from the groundbreaking observations of astronomer Fritz Zwicky in the 1930s to Vera Rubin's pivotal work in the 1970s, which solidified dark matter’s crucial role in galaxy formation. We explore theories about what dark matter might be, including exotic particles like WIMPs and axions, and discuss the cosmic web that dark matter helps weave throughout the universe. With fascinating insights into gravitational lensing and the cosmic microwave background, we uncover the mounting evidence that supports dark matter’s existence. Join us as we embark on the quest to understand this elusive component of our universe, revealing how it shapes the cosmos while remaining hidden in plain sight.