Dark matter isn’t so cold after all
The enigma of dark matter was already studied by Fritz Zwicky and Vera Rubin. For decades, it was depicted as a cold, listless skeleton that only draws galaxies together.
Sound Magnet: How Atoms Twist Sound into a Spiral
In a solid, atoms vibrate, transmitting sound. Sometimes this wave doesn't run straight but curls into a spiral, like a corkscrew entering a cork. In ordinary crystals, such 'sound vortices' are known, but in magnetic materials they had long eluded detection.