Gravitational-wave chirp. On 14 Sept 2015, LIGO caught two black holes (~36 & ~29 M
☉)
spiralling together and merging — spacetime itself ringing. The signal sweeps from
35 → 250 Hz
in ~0.2 s, peaks as they collide, then rings down. This trace is a stylised, time-compressed
reading with detector-style noise.
Abbott et al. 2016, PRL 116, 061102 ↗