A study published in Nature in August 2026 has reported evidence of vacuum birefringence, a phenomenon predicted by quantum electrodynamics (QED). It is based on observations of the magnetar 1E 1547.0-5408, which lies about 14,700 light-years from Earth.
The data come from NASA's Imaging X-ray Polarimetry Explorer (IXPE), which detected highly polarised X-rays from the magnetar. Polarisation reached up to 80% in some observations.
Vacuum birefringence is a quantum phenomenon in which a strong magnetic field makes the vacuum of space behave like a crystal. The vacuum then alters the properties and polarisation of light passing through it.
The effect was predicted in the 1930s by the physicists Werner Heisenberg and Hans Heinrich Euler, based on the principles of QED. In QED, the vacuum is not empty. It contains virtual particles, such as electron-positron pairs, that briefly appear and disappear because of quantum fluctuations. In extremely strong magnetic fields, these particles influence how light propagates, which changes its polarisation.
The effect becomes noticeable only in magnetic fields about 88 trillion times stronger than Earth's. Artificial magnets cannot produce fields of that strength.
Magnetars supply them naturally. A magnetar is a type of neutron star, formed when the core of a massive star collapses and leaves an extremely dense object with a powerful magnetic field. Magnetars have the strongest known magnetic fields in the universe, which makes them natural laboratories for studying vacuum birefringence.
The observation provides evidence for vacuum birefringence and supports QED under extreme conditions. It also adds to understanding of magnetars, cosmic environments and magnetic fields across the universe.
With reference to vacuum birefringence, consider the following statements:
Which of the statements given above are correct?
Consider the following statements:
Statement-I: A magnetar is used to study vacuum birefringence, since artificial magnets cannot produce the magnetic fields needed.
Statement-II: Magnetars have the strongest known magnetic fields in the universe.
Which one of the following is correct in respect of the above statements?
Identify the astronomical object on the basis of the following information:
