Ah, lasers. Those wonderful, super intense beams of light that we’ve seen used in headlights, projectors, and naturally, death rays. Like us, researchers at the Niels Bohr Institute at the University of Copenhagen figure there’s nothing lasers can’t do, and have figured out a way to use them to cool a bit of semiconducting material. This bit of black magic works using a membrane made of gallium arsenide and is based upon principles of quantum physics and optomechanics (the interaction between light and mechanical motion).Turns out, when a one millimeter square membrane of gallium arsenide is placed parallel to a mirror in a vacuum chamber and bombarded with a laser beam, an optical resonator is created between them that oscillates the membrane. As the distance between the gallium arsenide and the mirror changes, so do the membrane’s oscillations. And, at a certain frequency, the membrane is cooled to minus 269 degrees Celsius — despite the fact that the membrane itself is being heated by the laser. So, lasers can both heat things up and cool them down simultaneously, and if that confuses you as much as it does us, feel free to dig into the science behind this paradoxical bit of research at the source below. In other news, left is right, up is down, and Eli Manning is a beloved folk hero to all Bostonians.