3 facts
The third law of thermodynamics states that it's impossible to cool a system to absolute zero (0 Kelvin or -273.15 °C). As an object gets colder, it requires exponentially more energy to remove smaller amounts of heat, making the final step of reaching true zero an infinite challenge.
While space itself is extremely cold, scientists have achieved temperatures even lower than the cosmic background radiation in labs. Researchers at the University of Colorado Boulder cooled rubidium atoms to just 38 billionths of a degree above absolute zero, creating a Bose-Einstein condensate to study quantum phenomena.
When helium is cooled to near absolute zero, it loses all viscosity and friction, allowing it to flow without resistance. This bizarre quantum state enables it to defy gravity by forming a thin film that creeps up and over container walls, a phenomenon known as the Rollin film effect.