German researchers have developed a super-tiny steam engine that’s just a few thousandths of a millimeter wide. Although the engine sputters incessantly and isn’t developed enough to be used in the real world, the discovery could make it easier to produce ultra-efficient micro-engines in the future, according to researchers at the University of Stuttgart and the Max Planck Institute for Intelligent Systems. “The machine really does perform work,” said researcher Clemens Bechinger in a statement. “This was not necessarily to be expected, because the machine is so small that its motion is hindered by microscopic processes which are of no...