Meanwhile, in the vacuum around a magnetar…

NASA’s IXPE Studies Magnetar nasa.gov

Empty space is not supposed to have optical properties, yet the vacuum around a magnetar appears to twist X-rays exactly as quantum electrodynamics predicted in the 1930s. NASA's IXPE stared at 1E 1547.0−5408 — a stellar corpse with a magnetic field trillions of times Earth's — for more than 140 hours, and the light came back polarized in the telltale way. A 90-year-old prediction about nothing at all, finally caught in the act.