U researchers contribute to historical physics breakthrough

The first observation of gravity waves helps confirm Albert Einstein’s theory of relativity.

Keaton Schmitt

Researchers from the University of Minnesota helped detect a type of wave — predicted by Albert Einstein — emitted 1.3 billion years ago when two black holes collided.
 
 
The scientists confirmed they observed a gravitational wave, which provides stronger evidence than ever before for Einstein’s theory of general relativity. Experts say the news could create a new branch of astronomy and lead to practical technologies. 
 
 
General relativity compares how the mass of things like black holes bends space time with an apple thrown onto an outstretched sheet of linen, said Vuk Mandic, University physics professor and collaborator with the Laser Interferometer Gravitational-Wave Observatory — the mutli-university project that observed the wave. 
 
 
In the apple metaphor, when the apple strikes fabric, “waves” move away from it in the way gravity waves do, he said.
 
 
LIGO scientists detected the waves in September, Mandic said, but the team spent five months making sure the wave wasn’t caused by an environmental error or another source.
 
 
While scientists have tested general relativity before, they’ve never corroborated it on this large a scale, he said, adding the theory “came through with flying colors.”
 
 
It is the first strong evidence for the existence of very high-stellar-mass black holes and has other implications for science in general — for example as a tool for learning about the early structure of the universe, Mandic said. 
 
 
The discovery’s practical uses aren’t yet clear, but other breakthroughs that initially lacked a clear everyday benefit are now used commonly, like how general relativity is used in GPS systems, he said.
 
 
“The most important aspect of this [discovery] is … contributing to the general knowledge and culture of mankind,” Mandic said. “I’m sure that practical applications will come, but it’s a matter of time.”
 
 
The discovery may create an entirely new field of astronomy, said Evan Skillman, director of the Minnesota Institute for Astrophysics. 
 
 
Whenever experts find new kinds of information about the universe, it opens a new area of study, said Gwynne Crowder, a University researcher who works with LIGO.
 
 
“It is hard to undersell how big a deal this is,” Skillman said.
 
 
Still, it is possible there won’t be new discoveries after this one, said University physics professor Keith Olive. 
 
 
“No one knows how rare or common those kind of collisions [are],” said Olive.
 
 
Astronomy has seen expansions in the field before — but not all of them have had far-reaching implications. The discovery of radio waves helped researchers learn about the universe. But the 1987 detection of neutrinos — a type of fundamental particle — has yet to be observed since, he said. 
 
 
Skillman said he thinks advancement in detection tools and more sensitive equipment will let researchers detect waves more frequently over time. 
 
 
“The fact that they essentially turned things on and discovered one right away tells you that this is no fluke,” Skillman said. “This is just the first of a flood.”
 
 
Additional detections and data could be used to understand the demographics of black holes, Skillman said.
 
 
“These sorts of observations will allow astronomers to ask and answer completely independent questions,” he said.
 
 
Mandic said LIGO researchers wrote a paper to discuss possible implications of the discovery, which was submitted for review and should be released in coming weeks and months.