The void can produce particles if a strong enough field is applied. Physicists call this the Dirac–Klein paradox. Previously, explaining it required the most complex calculations of quantum field theory. But we can make do with a visual image: a tightly stretched rubber band with a knot. The knot is a particle. As long as the tension is moderate, it moves calmly. But when the stretching force exceeds a critical threshold — specifically, twice the energy contained in mass, as per the formula V > 2mc², where m is mass and c is the speed of light — the rubber band snaps. From the break, two oppositely twisted whirls fly out: a antiparticle and the original particle. This same threshold is known as the Schwinger limit.
This approach is part of the broader idea of analogue gravity, where the behavior of quantum systems is modeled using familiar media, be it rubber or flowing water. It helps us understand, without formulas, how the void becomes non-empty, and reveals an unexpected similarity between the physics of the microworld and the mechanics of everyday materials.
Oskar Klein proposed the paradox in 1929. Initially considered a mathematical curiosity, it is now key to understanding vacuum instability in strong fields.
In science fiction, antimatter often serves as an inexhaustible energy source — for example, in the warp drives of 'Star Trek' spaceships.