A bell struck by a hammer hums softer and softer. Its ring fades smoothly, like ripples on water after a stone is tossed in. A black hole behaves much the same way after colliding with another hole: it shudders, and those shudders, gravitational waves, fly off into space, gradually weakening.
Our Solar System isn't an island in the void: it's a sensitive web stretched in a dark cosmic corner. Planets circle their orbits like dewdrops on threads, and we are the spider sensing the faintest tremor. That tremor betrays the approach of the catastrophe astronomers call the Big Rip.
The universe sounds with silence. The lion's share of matter — about 85%—remains invisible, manifesting only through gravity. Back when Vera Rubin Vera Rubin showed that galaxies spin as if wrapped in unseen mass.