Nothing is colder than absolute zero, but there's a whole world beyond that point. For the first time, atoms have been put in a state where they can take on a range of negative absolute temperatures. This could deepen our understanding of subatomic particles - and perhaps even mysterious dark energy. Although we're used to talking about negative temperatures, such as -10 ℃, all temperatures on an ordinary thermometer are positive when measured in kelvin. On this scientific scale, which starts at absolute zero (-273.15 ℃), temperature is determined by the kinetic energy of particles. So a gas of slow particles is colder than a gas of fast-moving ones, and absolute zero corresponds to the point at which particles stop moving completely, which is why nothing can be colder.
展开▼
