For decades, physicists have wrestled with a paradox at the edge of the knowable: do black holes erase all memory of the matter they consume, or do they secretly carry hidden signatures of what they have swallowed? A new experimental framework now offers humanity its first empirical foothold on this question, using gravitational waves — the universe's own tremors — as a lens to peer into what may lie concealed beyond the event horizon. The work does not yet deliver an answer, but it transforms one of physics' deepest mysteries from philosophical conjecture into something the instruments of our