Dark matter acts as a cosmic glue that prevents galaxies from flying apart.

The concept of dark matter gained significant scientific traction in the 1970s through the work of astronomers Vera Rubin and Kent Ford. While observing the Andromeda Galaxy at the Lowell Observatory and Carnegie Institution, they discovered that stars at the outer edges were moving just as fast as those near the center. According to Newtonian physics, these outer stars should move much slower because there is less visible mass to hold them in orbit.This discrepancy, known as the galaxy rotation problem, suggested that an immense amount of invisible mass must be providing extra gravity. Modern calculations by institutions like NASA and the European Space Agency confirm that dark matter makes up approximately 85% of the universe's total matter. Without this 'missing mass,' the centrifugal force from a galaxy's rotation would overcome its gravitational binding energy, causing stars to fly off into deep space.Dark matter does not emit, absorb, or reflect light, making it impossible to observe directly with traditional telescopes. Scientists instead detect it by observing its gravitational effects on visible light and matter, a process often involving gravitational lensing. Large-scale simulations, such as the Illustris project, show that dark matter formed a 'cosmic web' early in the universe's history, acting as the scaffolding upon which all visible galaxies were built.