Casimir's Effect

Short answer: In 1948 the Dutch physicist Hendrik Casimir predicted that two uncharged, parallel conducting plates in a vacuum would be pushed together. In quantum theory, the vacuum is not empty but full of fluctuating electromagnetic fields.

The plates limit which field modes fit between them, so the pressure outside is greater than the pressure inside. The force is tiny and only matters at very small separations. Steven Lamoreaux measured it directly in 1997, at gaps of 0.6 to 6 micrometers, agreeing with theory to within about 5%. Engineers now consider it in the design of micromachines (MEMS). The dynamic version, which is what the Reel describes, was proposed by Gerald Moore in 1970. A mirror moving at a significant fraction of the speed of light could convert virtual photons into real, detectable ones. Moving a physical mirror that fast isn't practical. In 2011, Christopher Wilson and colleagues at Chalmers University of Technology in Sweden instead used a superconducting circuit, published in Nature. A SQUID (superconducting quantum interference device) changed the electrical length of a transmission line about 11 billion times a second, at an effective speed of a few percent of light speed. They detected microwave photons emitted in correlated pairs, the predicted signature, and called it the first observation of the dynamical Casimir effect. The footage shows two metal strips hanging side by side and drawing together. That's a visible-scale stand-in for illustration: real Casimir forces are only measurable at micrometer gaps.