In quantum electrodynamics (QED), space isn’t really empty. Virtual particle and antiparticle pairs continually pop up and disappear.
In the presence of very strong magnetic fields, the vacuum space is distorted and acts like a prism, changing the polarisation of light that passes through.
Vacuum birefringence is difficult to observe, but a team of scientists believe they have spotted promising signs by using the European Southern Observatory’s Very Large Telescope (VLT) in northern Chile to observe a group of pulsating neutron stars called “The Magnificent Seven.”
One particular neutron star – catchily named the RX J1856.5-3754 – is about 400 light-years away and has an extremely strong magnetic field, making it an ideal candidate for observing vacuum birefringence.
After inspecting the electromagnetic field around the star, the researchers found that a substantial amount of the emitted light was travelling in a restricted direction, and it had been linearly polarised by 16 per cent....