The cosmic detective story nobody asked for! When astronomers measured how fast stars orbit in galaxies, they found a massive problem - there's not enough visible mass to explain their movement. Instead of admitting their equations were wrong, physicists invented an invisible substance making up 85% of all matter. Batman would be proud of this shadow solution - can't see it, can't detect it directly, but it's apparently EVERYWHERE. The ultimate "trust me bro" of astrophysics! Next time your calculations don't add up, just invent an invisible force and call it a day. Science™!