In space, you can’t hear a black hole scream, but you can apparently hear it sing.
In 2003, astrophysicists collaborated with NASA’s orbiting Chandra X-ray observatory discovered a wave pattern in X-rays of a huge cluster of galaxies in the constellation Perseus. They were pressure waves — sound waves — 30,000 light-years across, radiating outward through the thin, ultra-hot gas that pervades galaxy clusters. They were caused by periodic outbursts from a supermassive black hole at the center of the cluster, 250 million light-years away and containing thousands of galaxies.
With an oscillation period of 10 million years, the sound waves acoustically corresponded to B flat major 57 octaves below middle C, a pitch that the black hole appears to have maintained for the past two billion years. Astronomers suspect these waves slow star formation and keep the gas in the cluster too hot to condense into new stars.
Chandra astronomers recently “sonified” these waves, accelerating the signals to 57 or 58 octaves above their original pitch and increasing their frequency by a trillion times to make them audible to the human ear. As a result, we others can now hear the intergalactic siren song.
Thanks to these new cosmic headphones, the black hole is from Perseus makes strange moans and growls it reminded that listener of the galloping tones marking an alien radio signal that Jodie Foster hears through headphones im Science-Fiction-Film „Contact“.
