OJ 287 is a supermassive black hole binary (SMBHB) 4 billion light-years from Earth. They have produced quasi-periodic optical outbursts going back approximately 120 years since at least 1887. The intrinsic brightness of the flashes corresponds to over a trillion times the Sun’s luminosity, greater than the entire Milky Way galaxy’s light output. Only recently have the outbursts been predicted in advance.
It’s too bad Einstein or Stephen Hawking aren’t around to comment on the video, it would be fascinating to hear what they might have to say.