This animation shows the inspiral and merger of two black holes with masses and spins consistent with the GW170104 observation. The top part of the movie shows the black hole horizons. The initial two black holes orbit each other, until they merge and form one larger remnant black hole. The shown black holes are spinning, and angular momentum is exchanged among the two black holes and with the orbit. The spin-axes of the black holes change, as visible through the colored patch on each black hole horizon, which indicates the north pole.
Finally, the slowed-down replay of the merger at the end of the movie makes it possible to observe the distortion of the newly formed remnant black hole, which decays quickly.
The remnant black hole is “Kicked” by the emitted gravitational waves, and moves upward.