In the 1970s, astronomer Vera Rubin observed that stars at the edges of spiral galaxies were moving just as fast as those near the center. According to Newtonian physics, they should have been moving much slower or flying off into space unless some unseen mass was holding them in place. Galaxy Clusters
The exact identity of dark matter remains unknown, though several leading theories exist: The quest for dark matter with Matt Bothwell Dark Matter
Most evidence suggests dark matter is "cold," meaning its particles move slowly relative to the speed of light. 🔭 Key Evidence In the 1970s, astronomer Vera Rubin observed that
Massive objects warp the space around them, bending light like a lens. By observing how light from distant galaxies is distorted, astronomers can map the "invisible" mass causing the effect, which consistently points to vast reservoirs of dark matter. 🧪 What Could It Be? 🔭 Key Evidence Massive objects warp the space
Dark matter makes up roughly , dwarfing the "ordinary" matter—stars, planets, and people—which accounts for less than 5%.
It does not interact with electromagnetic forces, meaning it is completely transparent.
It provides the "glue" that keeps galaxies from flying apart.