Neutron Star Provides First Observational Evidence Of ‘Vacuum Birefringence’ In Empty Space

Back in 1930, Werner Heisenberg and Hans Heinrich Euler predicted the existence of a weird phenomenon known as “vacuum birefringence,” wherein a strong magnetic field can affect the polarization of light. Now, this 80-year-old prediction of quantum electrodynamics (QED) — the theory that describes, among other things, the interaction between matter and light — has finally been observed in nature.