Which country has six months of night

Is it really dark for 6 months at the North Pole?

Counterpart to the midnight sun

Within the polar circles there is at least one day in the winter months on which the sun stays below the horizon even at noon. This phenomenon is called polar night. To a certain extent it is the counterpart of the midnight sun, in which the sun does not set for at least 24 hours in summer.

How are the northern lights created?

Countries with polar night

In the northern hemisphere, for example, you can experience the polar night in northern areas of Norway, Sweden, Finland, Canada, Russia and Greenland. The southern polar circle includes almost all of Antarctica.

Duration of the polar night

In the vicinity of the arctic circles, the polar night usually only lasts one day. The only time the sun does not rise there is on the day of the winter solstice. The further you move towards the poles, the longer the polar night lasts. The sun sets at the north and south poles at the autumn equinox and does not rise again until six months later, at the spring equinox.

In the northern arctic circle the winter half-year lasts from September to March, in the southern arctic circle from March to September:

How does the polar night come about?

Polar night and midnight sun arise due to the inclination of the earth's axis compared to its orbit around the sun. In the course of a year - i.e. a complete orbit around the sun - sunlight falls onto the earth's surface from different directions. This is also the reason why there are seasons on earth.

In December, the North Pole leans away from the sun, and it is winter in the northern hemisphere. In the southern hemisphere, winter begins in June when the south pole turns away from the sun.

At the poles and within the polar circles, the inclination of the earth's axis in winter means that the sun does not irradiate even areas that are currently on the “day side” of the earth. There is then polar night (see graphic).

Northern polar night on the day-night world map

Is it really dark for 6 months?

While it actually remains pitch dark for several months at the poles in winter, the days and weeks after the beginning and before the end of the polar night are characterized by twilight. According to the definition, the sun only has to be below the horizon during a polar night - its indirect rays can still partially illuminate the firmament.

In the vicinity of the polar circles, it remains relatively bright on the day of the winter solstice despite the polar night. This effect is intensified by the astronomical refraction.

What is earth shine?

No polar night at the Arctic Circle

The polar circles are defined by the fact that the center of the solar disk does not disappear below the horizon on the day of the summer solstice and does not rise above the horizon on the day of the winter solstice. In fact, the area of ​​the polar night does not begin directly at the polar circles, but a good bit further towards the poles. The Norwegian city of Bodø is just north of the Arctic Circle, but the sun rises on the shortest day of the year.

The main reason is the fact that the solar disk has a certain extent in the sky - so the sun is not a point source of light. While the center of the solar disk at the winter solstice near the Arctic Circle is just below the horizon at noon, the upper half peeps briefly over the horizon and thus interrupts the night.

This geographic shift in the polar night is amplified by a phenomenon called astronomical refraction. When it enters the earth's atmosphere, the sun's light is refracted - and redirected in such a way that the upper edge of the sun can also be seen in places where it should not be visible due to the geometry. For the same reason, you can sometimes experience the midnight sun in places just outside the Arctic Circle.

Refraction is also responsible for ensuring that day and night at the equinox are not of the same length.

Subjects: Seasons, sun, astronomy