A collaborative research team utilizing NASA’s Imaging X-ray Polarimetry Explorer (IXPE) has observed a magnetar exhibiting behavior that may confirm a 90-year-old prediction in quantum electrodynamics. The findings, published in the journal Nature, center on the magnetar 1E 1547-5408, a dense neutron star remnant with magnetic fields approximately a trillion times more powerful than the strongest magnets on Earth.

Between March and April 2025, researchers conducted more than 140 hours of coordinated observations using IXPE, NASA’s Neutron Star Interior Composition Explorer (NICER), and the CSIRO-operated Murriyang radio telescope in Australia. The data revealed X-ray polarization levels nearly three times higher than those observed in similar celestial objects. Because standard surface emission models cannot account for such high polarization, scientists point to the theory of vacuum birefringence as the likely cause.

First proposed in 1936, the theory of vacuum birefringence suggests that in the presence of extreme magnetic fields, the vacuum of space functions similarly to a prism, filtering light and enhancing its polarization. Simulations conducted by the research team indicate that this effect is necessary to explain the specific X-ray signatures recorded during the mission.

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"Our model suggests that reproducing the observed X-ray polarization signatures, while also satisfying the constraints set by radio observations, requires the presence of vacuum birefringence in the neutron star’s environment," stated Hoa Dinh Thi, a postdoctoral associate at Rice University and co-lead author of the study. Lead author Rachael Stewart, a Ph.D. candidate at George Washington University, noted that the discovery provides insights into the fundamental nature of reality.

The IXPE mission, a joint effort between NASA and the Italian Space Agency, plans to continue monitoring this magnetar and other similar sources to further validate these findings and explore additional quantum effects.

Source: NASA