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Evidence for Vacuum Birefringence Reported in Aug 2026
In Aug 2026, scientists report evidence that vacuum near a super-magnetic star behaves like a crystal, altering light travel and supporting quantum predictions that space is not truly empty. The findings come from observations of the magnetar 1E 1547.0-5408 using X-ray and radio polarimetry instruments.
Vacuum Birefringence:
| Dimension | Key Details |
|---|---|
| Classical definition of vacuum | According to classical physics, a vacuum is defined as complete nothingness. |
| Quantum electrodynamics (QED) | Quantum electrodynamics provides that so-called empty space is permeated by virtual particle pairs, such as electron-positron pairs, which continuously appear and vanish. |
| Influence of virtual particles | Under typical conditions, virtual particles exert negligible influence on the propagation of light. |
| Heisenberg and Euler prediction (1930s) | Heisenberg and Euler provide that within an extremely strong magnetic field, the quantum vacuum behaves analogously to a crystal, thereby altering the transmission of light. |
| Term and meaning | Vacuum birefringence is a phenomenon predicted by QED in which an extremely strong magnetic field causes the quantum vacuum to behave similarly to a birefringent crystal; “bi-” denotes two and “refringence” means refraction. |
| Birefringent material: key property | A birefringent material alters the behaviour of light depending on the direction of its polarisation. |
| Example of birefringent material | A calcite crystal is a classic example of a birefringent material. |
| Study target | The recent study targets magnetar 1E 1547.0-5408, located approximately 14,700 light-years away and classified as a rare radio-emitting magnetar. |
| Instruments utilised | The study uses three instruments: IXPE (Imaging X-ray Polarimetry Explorer) to measure X-ray polarisation; NICER, located on the International Space Station, for X-ray timing and spectral analysis; and Murriyang (Parkes radio telescope) for radio polarimetry to map the magnetic geometry. |
| Observation: X-ray linear polarisation degree (PD) | X-ray linear polarisation degree (PD) from the magnetar reaches about 65-80%, far higher than in typical X-ray sources. |
| Observation: PD vs X-ray energy | PD decreases with increasing X-ray energy, matching QED predictions for vacuum birefringence. |
| Observation: polarisation angle behaviour | The polarisation angle behaviour fits models where X-rays travel through a strongly magnetised quantum vacuum. |
| Interpretation of modelling | Models including vacuum birefringence fit the data much better than those without it. |