THE SUN THAT NEVER SETS: A PHENOMENON OF THE SOLSTICES

 Last June 21st marked the summer solstice, a phenomenon that, for the inhabitants of the northern hemisphere, represents the day with the most sunlight of the year. Conversely, for those in the southern hemisphere, it’s the day with the least amount of light. On the winter solstice, which occurs on December 21st, the situation is reversed.

The summer solstice takes place when the sun is positioned directly above the Tropic of Cancer. This coincides with the moment when, in its apparent motion along the ecliptic, the sun reaches its maximum declination. During the days of the summer solstice, a unique phenomenon occurs for inhabitants of regions located north of the Tropic of Cancer, that is, beyond 66° of declination: the Midnight Sun.

Naturally, this phenomenon also occurs around the winter solstice for regions located south of the Tropic of Capricorn.

In our hemisphere, the Midnight Sun can be admired from Canada, Greenland, the northern part of Russia, Norway, and Finnish and Swedish Lapland.

The term “Midnight Sun” refers to any period of light lasting more than 24 hours, up to a maximum of six months. For regions located exactly on the Tropic of Cancer, the sun never sets only on the summer solstice, while the further north you go, the longer the sun stays above the horizon for consecutive days. For instance, from North Cape, the northernmost point of continental Europe, the sun doesn’t set for 60 days, roughly from mid-May to the end of July, while from the Svalbard islands, the sun constantly stays above the horizon from the end of April to the end of August.

The extreme case happens at the North Pole, where the sun never sets for six straight months, only to disappear below the horizon for the remaining part of the year.