You may imagine vacuum as complete emptiness, as the very definition of nothing. But that’s not the case at all. Vacuum is humming with activity, as has now been demonstrated impressively in a study by researchers from Chalmers University of Technology in Göteborg, Sweden, RIKEN in Japan, the University of Michigan in the US and other institutions. They have created light basically out of nothing but the electromagnetic fields existing even in total vacuum.
Where does this contradiction come from that vacuum isn’t really ever empty? One of physics fundamental laws of physics, Heisenberg’s principle, states that even in vacuum virtual particles can exist. These are particles that appear only for such brief moments of time that they’re not noticeable to an observer. Indeed, vacuum is buzzing with all sorts of virtual particles and fields. One of Stephen Hawking’s most well-known predictions is that black holes emit light, which is an effect that relies on virtual particles. [...]