Tying a smoke ring in a knot sounds impossible - but University of Chicago physicists have done something similar by creating a vortex knot for the first time, in a container of fluid.
A change in the social position of a rhesus macaque can affect the expression of nearly 1,000 genes, perhaps partly explaining why poorer people tend to have worse health outcomes.
A new chemical analysis of lunar material collected by Apollo astronauts in the 1970s appears to disprove theories that the moon was created through a massive collision between Earth and a Mars-sized object 4.5 billion years ago.
Numbers above three are incomprehensible to people who don't speak a language that uses symbols for counting, say researchers at the University of Chicago.
