What event occurs on December 21-22 in the northern hemisphere?

The event that occurs on December 21-22 in the northern hemisphere is the Winter Solstice. This marks the shortest day and the longest night of the year due to the tilt of the Earth's axis away from the Sun. During this time, the Sun is at its lowest point in the sky at noon, resulting in minimal sunlight reaching the northern hemisphere.

The Winter Solstice signifies the beginning of winter and is significant culturally and scientifically as it represents a turning point when days begin to lengthen in the following months. This astronomical event has been observed and celebrated in various cultures throughout history.

In contrast, the Autumnal Equinox occurs around September 22-23 when day and night are approximately equal in length. The Vernal Equinox happens around March 20-21, marking the beginning of spring. The Summer Solstice, which takes place around June 21-22, is the longest day of the year when the Sun is at its highest point in the sky. Understanding the differences and characteristics of these events helps contextualize when and why the Winter Solstice is recognized on December 21-22.