NASA’s Imaging X‑ray Polarimetry Explorer (IXPE) spent over 140 hours observing the magnetar 1E …, measuring the polarization of its X‑ray emission.
The results, published Wednesday in Nature, show a polarization angle consistent with the theoretical prediction of vacuum birefringence in the magnetar’s ultra‑strong magnetic field.
Vacuum birefringence was first forecast in the 1930s by Werner Heisenberg and Hans Heinrich Euler within quantum electrodynamics, but has never been directly detected before.
Researchers caution that additional data are required to rule out other processes and to increase the statistical significance of the signal.