A study led by an MIT researcher deciphered for the first time the “ringing” of an infant black hole, which produces gravitational waves in a way similar to the way a bell produces sound, allowing them to predict the black hole’s mass and spin.
The scientists studied a newborn black hole that was created when two black holes collided. While waves caused by the violent collision had previously been detected, isolating the ringing from the resulting black hole opened up a new way to study the mysterious bodies whose gravity is so strong not even light can escape them, researchers said.
“We’re excited about this because . . . it shows that we can start doing this more precise test and start to understand black holes in a deeper sense,” said Maximiliano Isi, a NASA Einstein fellow in the Massachusetts Institute of Technology’s Kavli Institute for Astrophysics and Space Research.
The study was published in Physical Review Letters. Isi led the study alongside a five-person team, including co-author Matthew Giesler from the California Institute of Technology.
Showing that the ringing of gravitational waves can be used to accurately predict the mass and spin of black holes lent support to a century-old Albert Einstein theory about gravity, Isi said.
Einstein’s theory of general relativity explains how space, time, matter, and energy interact in different ways. He theorized the existence of gravitational waves, and how they could be used to find the composition of the objects that create them.
The ringing found by the scientists also supported the theory that black holes are “hairless,” a term used by scientists to indicate that a black hole has no characteristics other than mass, spin, and electrical charge, Isi said.
“We all expect general relativity to be correct, but this is the first time we have confirmed it in this way,” Isi said in a statement from MIT News. “This is the first experimental measurement that succeeds in directly testing the no-hair theorem.”
The data came from the Laser Interferometer Gravitational-Wave Observatory. LIGO is a scientific collaboration led by MIT and Caltech that includes institutions from all over the world. The organization first discovered gravitational waves in 2015 from the collision of the two black holes, and when the waves were translated into sound, they made a chirping noise, Isi said.
“What we’ve done in this study is go back to the data from the first detection of gravitational waves . . . and we reanalyzed it to look for a different kind of ‘ringing’ that has been all but ignored in previous analyses, and we were able to identify it,” Isi said.
Focusing on the last few milliseconds of the “chirp,” the researchers isolated the waves specific to the newly created black hole from the much stronger waves produced by the collision. This allowed them to identify a specific “tone” of the ringing that allowed them to predict the black hole’s mass and spin.
Isi said it was something that scientists had been trying to do for a long time, but it was thought that doing so would require technology not expected to be developed for another 20 years.
“We were very surprised by this because the common wisdom was that this should not work,” he said. “We were ecstatic.”
With a new black hole collision being detected every week, Isi said he is excited to see what the scientific community makes of this new way to study black holes and what he calls “the dark universe.” It also opens the door to the possibility of identifying and studying waves from other mystifying astrophysical objects, such as wormholes.
“This is very exciting. We’re going to be learning all types of things,” Isi said. “It’s a good time to be a gravitational scientist.”