This press release is available in German. What is normal to most people in winter has so far been impossible in physics: a minus temperature. On the Celsius scale minus temperatures are only ...

The most accurate thermometer in the known universe looks nothing like a thermometer. It is a copper vessel the size of a large cantaloupe, filled with ultrapure argon gas and studded with microphones ...

Nothing is colder than absolute zero, so it seems nonsensical to talk about negative temperature – but now there is a substance that must have just that. The revelation could shake up our ideas about ...