Astronomers have identified a potential ultra-fast pulsar spinning every 8.19 milliseconds close to Sagittarius A*, the supermassive black hole at the center of the Milky Way. If confirmed, this discovery could offer an unprecedented opportunity to test Einstein’s General Relativity in one of the most extreme environments in the universe.
The pulsar was found as part of the Breakthrough Listen Galactic Center Survey, a project designed to probe the heart of our galaxy for pulsars and signals of extraterrestrial life. Researchers, led by Karen I. Perez from Columbia University, suggest that this new pulsar candidate might serve as a highly accurate cosmic clock.
How Pulsars’ Regular Pulses Help Measure the Cosmos
Pulsars are dense remnants of stars that spin rapidly, emitting beams of radiation. These beams sweep across space, creating regular pulses that can be detected on Earth. The timing of these pulses is incredibly stable, earning pulsars the title of “cosmic clocks.” Millisecond pulsars, which spin even faster than regular pulsars, are particularly useful for precise measurements.
However, the turbulent environment surrounding Sagittarius A* has made it difficult to study pulsars in this part of the Milky Way. According to the team at Columbia University, the Breakthrough Listen Galactic Center Survey is one of the most sensitive radio surveys conducted in this region, designed to uncover new pulsars despite the chaotic forces at play.
A visual representation of the Green Bank Telescope capturing data from the Milky Way’s center. Credit: Danielle Futselaar / Breakthrough Listen
Can Einstein’s Theory Survive a Black Hole?
One of the most thrilling aspects of this discovery, published in The Astrophysical Journal, is the opportunity to test Einstein’s General Theory of Relativity near a supermassive black hole. Sagittarius A*, with a mass about four million times that of the Sun, exerts an immense gravitational force on objects around it. As explained by research co-author Slavko Bogdanov from Columbia University:
“Any external influence on a pulsar, such as the gravitational pull of a massive object, would introduce anomalies in this steady arrival of pulses, which can be measured and modeled.”
Tracking the timing of a pulsar’s pulses near such a massive object could provide new insights into the effects of gravity in extreme conditions. This would be an unprecedented opportunity to test aspects of General Relativity that have not been observable in such a powerful gravitational environment before.
Graph showing orbital period versus eccentricity for different stellar systems near a supermassive black hole. Credit: The Astrophysical Journal
Open Collaboration in the Search for Answers
Given the importance of this discovery, follow-up observations are already in progress to confirm the pulsar’s existence and behavior. To encourage further collaboration, the team behind the Breakthrough Listen initiative has made their data publicly available.
This decision allows other research teams around the world to independently analyze the findings and explore related scientific questions. Karen I. Perez, who led the study, expressed excitement about what the additional observations could reveal.
“We’re looking forward to what follow-up observations might reveal about this pulsar candidate,” Perez said. “If confirmed, it could help us better understand both our own Galaxy, and General Relativity as a whole.”