In space you’ll be able to’t hear a black hole scream, but apparently you’ll be able to hear it sing.
In 2003 astrophysicists working with NASA’s orbiting Chandra X-ray Observatory detected a pattern of ripples within the X-ray glow of a large cluster of galaxies within the constellation Perseus. They were pressure waves — that’s to say, sound waves — 30,000 light-years across and radiating outward through the skinny, ultrahot gas that suffuses galaxy clusters. They were attributable to periodic explosions from a supermassive black hole at the middle of the cluster, which is 250 million light-years away and incorporates hundreds of galaxies.
With a period of oscillation of 10 million years, the sound waves were acoustically akin to a B-flat 57 octaves below middle C, a tone that the black hole has apparently been holding for the last two billion years. Astronomers suspect that these waves act as a brake on star formation, keeping the gas within the cluster too hot to condense into recent stars.
The Chandra astronomers recently “sonified” these ripples by speeding up the signals to 57 or 58 octaves above their original pitch, boosting their frequency quadrillions of times to make them audible to the human ear. In consequence, the remaining of us can now hear the intergalactic sirens singing.
Through these recent cosmic headphones, the Perseus black hole makes eerie moans and rumbles that reminded this listener of the galumphing tones marking an alien radio signal that Jodie Foster hears through headphones within the science fiction film “Contact.”
As a part of an ongoing project to “sonify” the universe, NASA also released similarly generated sounds of the brilliant knots in a jet of energy shooting from a large black hole at the middle of the humongous galaxy often known as M87. These sounds reach us across 53.5 million light-years as a stately succession of orchestral tones.
One more sonification project has been undertaken by a gaggle led by Erin Kara, an astrophysicist on the Massachusetts Institute of Technology, as a part of an effort to make use of light echoes from X-ray bursts to map the environment around black holes, much as bats use sound to catch mosquitoes.
All that is an outgrowth of “Black Hole Week,” an annual NASA social media extravaganza, May 2-6. Because it happens this week provides a prelude to big news on May 12, when researchers with the Event Horizon Telescope, which in 2019 produced the primary image of a black hole, are to announce their latest results.
Black holes, as decreed by Einstein’s general theory of relativity, are objects with gravity so strong that nothing, not even light, much less sound, can escape. Paradoxically, they may also be the brightest things within the universe. Before any type of matter disappears perpetually right into a black hole, theorists surmise, it will be accelerated to near-light speeds by the opening’s gravitational field and heated, swirling, to thousands and thousands of degrees. This may spark X-ray flashes, generate interstellar shock waves and squeeze high-energy jets and particles across space like a lot toothpaste from a tube.
In a single common scenario, a black hole exists in a binary system with a star and steals material from it, which accretes right into a dense, vivid disk — a visual doughnut of doom — that sporadically produces X-ray outbursts.
Using data from a NASA instrument called the Neutron Star Interior Composition Explorer — NICER — a gaggle led by Jingyi Wang, an M.I.T. graduate student, sought echoes or reflections of those X-ray blasts. The time delay between the unique X-ray blasts and their echoes and distortions attributable to their nearness to the weird gravity of black holes offered insight into the evolution of those violent bursts.
Meanwhile, Dr. Kara has been working with education and music experts to convert the X-ray reflections into audible sound. In some simulations of this process, she said, the flashes go all the way in which across the black hole, generating a telltale shift of their wavelengths before being reflected.
“I just love that we will ‘hear’ the overall relativity in these simulations,” Dr. Kara said in an email.
Eat your hearts out, Pink Floyd.
