How to Remove Heat Down to a Millionth of a Kelvin

The majority of the universe has a temperature of two point seven degrees above absolute zero. Only very unusual circum es, he write, can make anything colder than those micro waves in the cosmic microwave background radiation. Nothing in the universe is known to be colder than about one kalvin except in certain physic laboratories on earth. There the record low temperature achieved is below one billionth of a kelvin.