Quantum electrodynamics predicts that empty vacuum in an ultra-strong magnetic field can change light's polarization. Scientists studied a magnetar (a neutron star with a record-breaking magnetic field) and saw unusually high polarization of its X-rays, which can only be explained by the vacuum's influence. So, does space around such stars act like a giant prism?
According to quantum theory, in an ultra-strong magnetic field, emptiness is no longer empty. It becomes akin to a crystal that transmits light differently—like polarized sunglasses filtering out glare. This effect, predicted by pioneers like Richard Feynman, has waited nearly a century for direct proof.
The IXPE X-ray telescope aimed at the magnetar 1E 1547.0-5408—a dead star with a magnetic field billions of times stronger than anything in Earth's labs. Its radiation's polarization—how much the light waves are 'combed'—was measured. At typical medical X-ray energies, it reached 65%, sometimes soaring to 80%.
As energy increased, polarization dropped sharply. Only one explanation fits: the vacuum around the star bends light like a crystal. Curiously, the first radio pulsar—also a neutron star—was mistaken for an alien signal by Jocelyn Bell Burnell in 1967. Today we know: the signals are strange, but nature is even stranger.
🎯 The magnetic field of this magnetar is 100 billion times stronger than a fridge magnet's: it can tear apart water molecules from a thousand kilometers away.