The spacecraft is also equipped to detect the Venusian equivalent of earthquakes.

ECONOMIST: Planetary science

Nor is Phoenix equipped to detect micro-organisms, though it will be able to sniff out organic molecules if these are around, and that will be a tantalising clue.

ECONOMIST: Space exploration

Fortunately, then, evolution has equipped mammals with the ability to detect by smell chemicals whose concentrations vary with differences in the MHC of the producer.

ECONOMIST: Perfume science