On March 11, 2026, a groundbreaking study published in the journal Nature shed new light on one of the most dazzling phenomena in the cosmos: superluminous supernovae. These extraordinary stellar explosions, which can outshine typical supernovae by more than tenfold and remain luminous for extended periods, have baffled astronomers since their discovery in the early 2000s. The new research attributes their extraordinary brightness and longevity to the intense radiation emitted by a newborn magnetar—a highly magnetized, rapidly spinning neutron star formed in the aftermath of a star’s death. Remarkably, this discovery also marks the first time scientists have directly witnessed the birth of a magnetar, with the key to unraveling the mystery lying in a subtle effect predicted by Einstein’s general theory of relativity.
A magnetar is an exotic type of neutron star, itself a dense remnant left behind when a massive star (roughly 10 to 25 times the mass of the Sun) runs out of nuclear fuel and collapses. Neutron stars are among the most extreme objects in the universe: a teaspoon of neutron star material weighs as much as Mount Everest. When these stars spin rapidly and emit beams of radiation from their magnetic poles, they are known as pulsars. Magnetars take this extremity to a new level, boasting magnetic fields up to a thousand times stronger than typical neutron stars, and often spinning at nearly the speed of light.
Until now, astrophysicists had only speculated that magnetars might be responsible for powering superluminous supernovae. But proving this hypothesis was challenging due to the complexity of the processes involved and the rarity of these luminous explosions. The breakthrough came with the observation of a new superluminous supernova, designated SN 2024afav, which erupted about a billion light-years from Earth in late 2024. Over a span of 200 days, astronomers at the Las Cumbres Observatory (LCO) meticulously monitored SN 2024afav’s brightness and noticed a curious pattern: its light periodically dimmed and brightened, with the intervals between these fluctuations steadily decreasing over time.
Joseph Farah, a graduate student based at the LCO and the University of California, Santa Barbara, led the study that decoded this enigmatic light curve. After extensive analysis, Farah and his colleagues concluded that the only plausible explanation for the observed oscillations was the presence of a rapidly spinning magnetar at the core of the supernova. The magnetar’s powerful magnetic field twists and contorts as it spins, unleashing enormous amounts of energy that heat the surrounding gas and debris, thereby sustaining the supernova’s intense glow.
But what caused the periodic dimming and brightening? This is where Einstein’s general relativity played a crucial role. Surrounding the newborn magnetar was a swirling disk of matter, slightly tilted relative to the star’s spin axis. The magnetar’s immense gravity and rapid spin caused a relativistic effect known as Lense-Thirring precession—essentially, the dragging of spacetime around a massive, rotating object. This effect caused the disk to wobble like a spinning top, periodically blocking the magnetar’s radiation from the perspective of an observer on Earth.
Because astronomers were viewing the system from the side, along the magnetar’s equator, this wobbling disk acted much like a shutter on a projector, causing the supernova’s brightness to oscillate. As the magnetar consumed material from the disk, the disk’s radius shrank, accelerating the wobble and resulting in more frequent dips in brightness until the disk eventually disappeared altogether. This dynamic interplay between the magnetar’s spin, magnetic field, and the warped spacetime around it produced a unique signature that perfectly matched the observations.
The study’s findings represent the most compelling evidence yet for magnetars as the engines behind superluminous supernovae. “Other possible energy sources wouldn’t produce such a pattern,” said Daniel Kasen, an astrophysicist at the University of California, Berkeley, who originally proposed the magnetar model for superluminous supernovae in 2010 and contributed helpful discussions to the new paper. “A magnetar can act as a powerful engine that lights up the supernova to extraordinary brightness.”
Beyond solving a long-standing astronomical mystery, this discovery opens exciting new avenues for exploring fundamental physics. Because magnetars exist in some of the most extreme environments in the universe, they provide natural laboratories