‘Scientists at Chalmers have succeeded in creating light from vacuum - observing an effect first predicted over 40 years ago. In an innovative experiment, the scientists have managed to capture some of the photons that are constantly appearing and disappearing in the vacuum.’

Our concept of a vacuum is something that has no matter which, in most cases, is a good enough definition. However, modern physics states that this vacuum is filled with virtual particles which come in and out of existence for such short periods of time that they cannot be detected (and if they are detected, they are no longer virtual particles). Most of the time, virtual particles are produced in pairs with a virtual antiparticle so that they annihilate each other fairly quickly.

The dynamic Casimir effect (not the static one which has been investigated in more depth) occurs when a mirror is brought to speeds near that of light. If a virtual photon collides with this fast-moving mirror, it can often be separated from its virtual antiparticle. This leaves us with light! 

Rather than having a mirror travelling at speeds near that of light (which is impossible for our current standards) the scientists used a rapidly changing magnetic field to cause a superconductor to vibrate at a fourth of the speed of light which works to the same effect.