Scientists simulate neutron star’s violent death as black hole cracks it like an egg
By isabelle // 2025-06-11
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  • Astronomers used supercomputers to simulate a neutron star being torn apart by a black hole, revealing violent "starquakes" and shock waves.
  • The neutron star's crust fractures under tidal forces, producing fast radio bursts detectable by advanced telescopes like Caltech’s DSA-2000.
  • Monster shock waves and a fleeting "black hole pulsar" appear before the star vanishes, emitting high-energy signals like X-rays or gamma rays.
  • GPU-powered supercomputers enabled unprecedented simulations, predicting electromagnetic signatures to help detect these never-before-seen cosmic collisions.
  • Future upgrades to gravitational wave detectors may allow astronomers to observe neutron star-black hole mergers minutes before they happen.
Astronomers have harnessed the power of supercomputers to simulate the final, violent moments of a neutron star as it is torn apart by a black hole. The research, led by Caltech astrophysicist Elias Most, reveals how the star’s surface fractures like an eggshell, unleashing monstrous shock waves and fleeting “black hole pulsars” before vanishing into oblivion. Published in The Astrophysical Journal Letters, these simulations provide the most detailed look yet at one of the universe’s most extreme events — a collision that could soon be detected by Earth’s most advanced telescopes. For years, scientists have theorized about what happens when a neutron star — a city-sized stellar corpse so dense that a teaspoon of its material weighs billions of tons — is swallowed by a black hole. Now, thanks to GPU-powered supercomputers, researchers have finally modeled the cataclysm in stunning detail. The simulations show how the black hole’s immense gravity shears the neutron star’s surface, triggering violent “starquakes” that ripple through its magnetic field. These quakes produce Alfvén waves, which transform into powerful radio bursts detectable from Earth.

Starquakes and cosmic cracks

The neutron star’s demise begins with its crust cracking under the black hole’s tidal forces. “The neutron star’s crust will crack open just like the ground in an earthquake,” Most explained. “The black hole’s gravity first shears the surface, causing quakes in the star and the opening of rifts.” These fractures send magnetic shockwaves racing across the star’s surface, generating fast radio bursts (FRBs), mysterious millisecond-long signals that have puzzled astronomers for years. Caltech’s upcoming Deep Synoptic Array-2000 (DSA-2000), a network of 2,000 radio dishes in Nevada, may soon detect these final cosmic cries. “Before this simulation, people thought you could crack a neutron star like an egg, but they never asked if you could hear the cracking,” Most said. “Our work predicts that, yes, you could hear or detect it as a radio signal.”

Monster shock waves and black hole pulsars

But the destruction doesn’t stop there. As the neutron star is consumed, the simulation reveals “monster shock waves”—some of the most powerful ever theorized — exploding outward. These shocks, stronger than those from the initial cracking, could produce a second detectable radio burst. Then, in a final twist, the black hole briefly transforms into a “black hole pulsar,” mimicking the spinning beams of a lighthouse before fading into darkness. “When the neutron star plunges into the black hole, the monster shock waves are launched,” said Yoonsoo Kim, a Caltech graduate student and lead author of the shock wave study. “After the star is sucked in, whipping winds are formed, creating the black hole pulsar. But the black hole cannot sustain its winds and will become quiet again within seconds.” This fleeting phenomenon occurs as the black hole expels the neutron star’s magnetic field, creating a pulsar-like effect for less than a second before vanishing. The event could emit high-energy X-rays or gamma rays, offering astronomers another way to spot these cosmic collisions. The key to these discoveries lies in advanced computing. The team used the Perlmutter supercomputer at Lawrence Berkeley National Laboratory, equipped with graphics processing units (GPUs) typically used in video games and AI. The simulations mark a major leap in understanding neutron star-black hole mergers, which have never been directly observed. While gravitational wave detectors like LIGO have spotted black hole collisions and neutron star mergers, a confirmed neutron star-black hole event remains elusive. These new models provide a roadmap for astronomers to identify such events by their electromagnetic signatures.

A new era of cosmic discovery

The research underscores how far astrophysics has come since Einstein predicted gravitational waves over a century ago. The findings also highlight the importance of interdisciplinary collaboration. By combining gravitational wave data with electromagnetic observations, scientists hope to piece together the full story of these cosmic collisions. Future upgrades to LIGO could detect mergers up to a minute before they occur, giving telescopes precious time to capture the accompanying light shows. For now, the simulations stand as a testament to human ingenuity and a digital window into the universe’s most violent events. As researchers refine their models and telescopes grow more sensitive, the secrets of neutron stars and black holes may soon be revealed in unprecedented detail. Sources for this article include: LiveScience.com CalTech.edu Gizmodo.com
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