'Ringing' black hole validates Einstein's general relativity 10 years ahead of schedule

September 12, 2019

For the first time, astrophysicists have heard a black hole ringing like a bell. By reanalyzing the first black hole merger ever detected, the astrophysicists measured the gravitational wave 'tones' emitted following the event. The breakthrough comes 10 years earlier than expected and confirms that the properties of black holes are just as Einstein predicted in his theory of general relativity in 1915.

"Previously it was believed these tones were too faint to be detected, yet now we are able to," says study co-author Will Farr. "Just like the measurement of atomic spectra in the late 1800s opened the era of stellar astrophysics and classifying and understanding stars, this is the opening of the era of black hole spectra and understanding black holes and the general relativity that sits behind them."

Farr is an associate professor at Stony Brook University in New York and group leader for gravitational wave astronomy at the Flatiron Institute's Center for Computational Astrophysics in New York City. He and his colleagues present their findings September 12 in Physical Review Letters.

When two black holes merge into one, the resulting supersized black hole wobbles like a struck bell. The reverberations emit gravitational waves at characteristic tones that fade away as the black hole settles. The so-called 'no-hair theory' states that these tones -- and all other external properties of a black hole -- depend only on the black hole's mass and rotation, just as Einstein's general relativity predicts. Some scientists, however, propose that reality is hairier and that effects like quantum mechanics play a role as well.

Scientists knew that detecting a black hole's tones could settle the debate. But the tones were thought to be too quiet to be detected by the current-generation gravitational wave detectors LIGO and Virgo.

In the new study, the astrophysicists combined simulations of black hole mergers with a reanalysis of the first gravitational waves ever detected. Those waves came from the merger of two black holes. The analysis led to the identification of two independent tones emitted by the newly combined black hole. The pitch and decay rates of these tones lined up with Einstein's general relativity. The no-hair theory stood triumphant.

Farr says that with new data analysis and with LIGO and Virgo continuing to observe black hole mergers, tests from the observatories will become more precise. The added precision will likely lead to additional detections of black hole tones and an improved understanding of the exotic objects.

Farr collaborated on the study with Maximiliano Isi of the Massachusetts Institute of Technology and the astrophysicists Matt Giesler, Mark Scheel and Saul Teukolsky of the California Institute of Technology.

Simons Foundation

Related Black Hole Articles from Brightsurf:

Black hole or no black hole: On the outcome of neutron star collisions
A new study lead by GSI scientists and international colleagues investigates black-hole formation in neutron star mergers.

The black hole always chirps twice: New clues deciphering the shape of black holes
A team of gravitational-wave scientists led by the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) reveal that when two black holes collide and merge, the remnant black hole 'chirps' not once, but multiple times, emitting gravitational waves--intense ripples in the fabric space and time--that inform us about its shape.

Wobbling shadow of the M87 black hole
New analysis from the Event Horizon Telescope (EHT) Collaboration reveals the behavior of the supermassive black hole in the center of the M87 galaxy across multiple years, indicating the crescent-like shadow feature appears to be wobbling.

How to have a blast like a black hole
Scientists at Osaka University have created magnetized-plasma conditions similar to those near a black hole using very intense laser pulses.

Black hole collision may have exploded with light
Astronomers have seen what appears to the first light ever detected from a black hole merger.

Black hole's heart still beating
The first confirmed heartbeat of a supermassive black hole is still going strong more than ten years after first being observed.

Black hole team discovers path to razor-sharp black hole images
A team of researchers have published new calculations that predict a striking and intricate substructure within black hole images from extreme gravitational light bending.

Planets around a black hole?
Theoreticians in two different fields defied the common knowledge that planets orbit stars like the Sun.

Black hole mergers: Cooking with gas
Gravitational wave detectors are finding black hole mergers in the universe at the rate of one per week.

Going against the flow around a supermassive black hole
At the center of a galaxy called NGC 1068, a supermassive black hole hides within a thick doughnut-shaped cloud of dust and gas.

Read More: Black Hole News and Black Hole Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.