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A violent stellar disruption recorded in 2024 has provided astronomers with the most comprehensive evidence to date of a black hole warping the fabric of spacetime. This phenomenon, scientifically identified as frame-dragging or the Lense-Thirring effect, was observed within the core of galaxy LEDA 145386, located approximately 400 million light-years from Earth. The detection of this event offered a rare opportunity to witness general relativity in action in real-time.
LEDA 145386: evidence of spacetime distortion via stellar destruction
The detection of this event offered a rare opportunity to witness general relativity in action in real-time. According to astrophysicist Cosimo Inserra of Cardiff University, these observations serve as a profound validation of century-old physical predictions while offering deeper insights into the nature of Tidal Disruption Events (TDEs), where immense gravitational forces reduce a star to debris.
Frame-dragging is a fundamental prediction of general relativity that can be conceptualized through the analogy of a spoon rotating in honey, where the surrounding medium moves in tandem with the central object. In gravitational terms, any entity possessing mass deforms the local spacetime, and if that mass rotates, it induces a corresponding torsion in the cosmic fabric.
While frame-dragging has been documented previously, including its measurable impact on satellites orbiting the Earth, the scale and intensity observed in this distant galaxy provide an unprecedented perspective on the behavior of massive celestial bodies.
The 2024 discovery in LEDA 145386
While the phenomenon of frame-dragging is measurable near Earth, its effects remain remarkably subtle. To observe this occurrence in a more pronounced state, astronomers must look toward supermassive black holes with masses millions of times greater than that of the Sun, which serve as exceptional laboratories for studying general relativity. However, the immense distances to these cosmic entities often preclude detailed investigation of their more nuanced activities. Consequently, researchers frequently depend on catastrophic occurrences, such as a Tidal Disruption Event (TDE), to measure elusive gravitational behaviors that would otherwise remain undetectable.
The black hole situated at the center of the galaxy LEDA 145386, possessing a mass approximately 5 million times that of the Sun, recently provided such a research opportunity. In January 2024, the Zwicky Transient Facility recorded an intense surge in luminosity consistent with a TDE—essentially the radiant energy emitted as a passing star is torn apart by overwhelming gravitational forces. As explained by astronomer Santiago del Palacio of Chalmers University, the star's material does not vanish immediately but instead forms an orbiting debris disk that gradually falls toward the event horizon.
Detailed multi-wavelength observations of the LEDA 145386 event revealed a highly unusual and significant pattern in the aftermath of the stellar destruction. Every 19.6 days, the intensity of X-ray emissions varied by more than an order of magnitude, a cycle that was precisely synchronized with radio wave fluctuations varying by over four orders of magnitude. This periodic oscillation in both X-ray and radio signals suggests a rhythmic process occurring within the accretion disk, providing a unique signature of the black hole's interaction with the surrounding spacetime fabric.
A Tidal Disruption Event occurs when the gravitational pull—or tidal forces—of a black hole overcomes a star's internal gravity, violently dismembering its structure. Rather than an instantaneous disappearance, the stellar remains spiral into a disk of superheated plasma. The recent observations from LEDA 145386 demonstrate that the resulting luminosity and the behavior of the accreting material can act as a precise indicator for measuring the Lense-Thirring effect, offering a real-time view into how rotating massive bodies twist the very geometry of the Universe.
The gyroscopic precession of accretion structures
Not all material from the decimated star is consumed by the black hole; instead, a significant portion is accelerated along magnetic field lines toward the poles. This process culminates in the violent ejection of matter into deep space at relativistic speeds, creating immense jets that travel near the speed of light. While the accretion disk surrounding the black hole primarily emits high-energy X-ray radiation, the synchrotron acceleration within these jets produces distinct radio waves. The synchronized fluctuations observed in both wavelengths suggest that the entire structure—comprising both the disk and the jet—is precessing like a spinning top, a direct manifestation of the frame-dragging effect.
According to co-lead author Yanan Wang of the Chinese Academy of Sciences, the high-amplitude, quasi-periodic variability observed across different bands indicates a rigid coupling between the accretion disk and the jet. This unified structure precesses like a gyroscope around the rotational axis of the black hole. Computational models simulating an oscillating disk and jet system have yielded results consistent with these observations, confirming that active supermassive black holes, such as the one in LEDA 145386, serve as exceptional laboratories for investigating accretion processes, jet formation, and the fundamental tenets of general relativity.
By demonstrating that a black hole can physically drag the surrounding spacetime, researchers are gaining a deeper understanding of the underlying mechanics of the frame-dragging process. This interaction is comparable to the way a rotating charged object generates a magnetic field; in this instance, a massive rotating body—the black hole—generates a gravitomagnetic field. This field profoundly influences the motion of nearby stars and other cosmic entities. These findings represent a significant milestone in astrophysics, as they bridge the gap between theoretical predictions of spacetime torsion and the observable dynamics of the universe’s most extreme environments.
The research has been published in Science Advances.
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