Einstein's Prediction Confirmed: Star Seen Wobbling Near Black Hole

A Cosmic Discovery: Observing a Spacetime Vortex

The universe has once again amazed scientists with a groundbreaking discovery. Researchers have successfully observed a swirling vortex in spacetime, caused by a rapidly rotating black hole. This observation marks the first time such an event has been recorded and is detailed in a study published in Science Advances.

Understanding Frame-Dragging

The phenomenon, known as Lense-Thirring precession or frame-dragging, describes how black holes twist the fabric of spacetime around them. This effect can drag nearby objects, such as stars, and cause their orbits to wobble. The discovery provides a unique opportunity to test some of the most fundamental predictions of Einstein's theory of general relativity.

The Discovery of the Swirling Vortex

The team, led by the National Astronomical Observatories at the Chinese Academy of Sciences, studied AT2020afhd, a tidal disruption event (TDE) where a star was torn apart by a supermassive black hole. As the star was shredded, a swirling disk formed around the black hole, composed of the remnants of the star. From this disk, powerful jets of matter were ejected at nearly the speed of light.

Through careful analysis of X-ray and radio signals from the event, the researchers observed that both the disk and the jet were wobbling in unison, repeating every 20 days. This rhythmic change provided critical evidence for the existence of the frame-dragging effect.

Confirming Einstein’s Prediction

First theorized by Einstein in 1913 and later formalized by Lense and Thirring in 1918, the observation confirms a long-standing prediction of general relativity. This discovery opens new avenues for studying black hole spin, accretion physics, and the formation of jets.

Dr. Cosimo Inserra, a Reader in the School of Physics and Astronomy at Cardiff University and one of the paper's co-authors, emphasized the significance of the findings. He stated, "Our study shows the most compelling evidence yet of Lense-Thirring precession—a black hole dragging space time along with it in much the same way that a spinning top might drag the water around it in a whirlpool."

"This is a real gift for physicists as we confirm predictions made more than a century ago. Not only that, but these observations also tell us more about the nature of TDEs—when a star is shredded by the immense gravitational forces exerted by a black hole."

"Unlike previous TDEs studied, which have steady radio signals, the signal for AT2020afhd showed short-term changes, which we were unable to attribute to the energy release from the black hole and its surrounding components. This further confirms the dragging effect in our minds and offers scientists a new method for probing black holes."

How the Team Observed the Phenomenon

To identify the frame-dragging effect, the team modeled X-ray data from the Neil Gehrels Swift Observatory (Swift) and radio signal data from the Karl G. Jansky Very Large Array (VLA). Further analysis using electromagnetic spectroscopy helped describe and identify the process.

"By showing that a black hole can drag space time and create this frame-dragging effect, we are also beginning to understand the mechanics of the process," explains Dr. Inserra. "So, in the same way a charged object creates a magnetic field when it rotates, we're seeing how a massive spinning object—in this case a black hole—generates a gravitomagnetic field that influences the motion of stars and other cosmic objects nearby."

"It's a reminder to us, especially during the festive season as we gaze up at the night sky in wonder, that we have within our grasp the opportunity to identify ever more extraordinary objects in all the variations and flavors that nature has produced."

Additional Information

For more details, refer to the following publication:

Yanan Wang et al, Detection of disk-jet coprecession in a tidal disruption event, Science Advances (2025). DOI: 10.1126/sciadv.ady9068