Question

how has the phenomenon of 'midnight sun' come about

Answer 1

The opposite phenomenon, polar night, occurs in winter, when the sun stays below the horizon throughout the day. ... At extreme latitudes, the midnight sun is usually referred to as polar day. At the poles themselves, the sun rises and sets only once each year on the equinox

Answer 2

The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the sun remains visible at the local midnight.