Heat can flow backwards in a gas so thin its particles never touch

A surprising reversal of our usual understanding of the second law of thermodynamics shows that it may be possible for heat to move in the “wrong” direction, flowing from a cold area to a warm one

​A surprising reversal of our usual understanding of the second law of thermodynamics shows that it may be possible for heat to move in the “wrong” direction, flowing from a cold area to a warm one A surprising reversal of our usual understanding of the second law of thermodynamics shows that it may be possible for heat to move in the “wrong” direction, flowing from a cold area to a warm one