When two compact bodies orbit, they radiate gravitational waves — ripples in spacetime that carry energy away. The orbit shrinks, they speed up, and the wave climbs in both pitch and volume: the chirp that LIGO first heard on 14 September 2015.
To leading order the frequency obeys df/dt ∝ f⁷¹⃗³ and a single combination of the masses — the chirp mass ℳ = (m₁m₂)³⃗⁵/(m₁+m₂)¹⃗⁵ — sets the whole sweep. Trade mass between the two bodies and, as long as ℳ is unchanged, the waveform is unchanged.
Heavier binaries are louder but chirp lower and end sooner: their merger frequency falls as 1/M while the sweep runs faster. From that one chirp, astronomers read off the masses of black holes they will never see.
Frequencies here are shown in a compressed band so each wave is countable; the chirp-mass scaling laws on screen are exact.
The simulation stopped unexpectedly — the lesson continues without it. You can move on; nothing you did was wrong.