Dec 21 Winter Solstice; Shortest Day Longest Night of the Year

We living in the northern hemisphere of the earth experience the longest night and shortest day of the year on December 21. This day is known as the Winter Solstice in the northern hemisphere. On this day people living in the southern hemisphere like the inhabitants of Australia will experience the longest day and shortest night of the year or the Summer Solstice. From December 22, the duration of the day will start to increase gradually in the northern hemisphere.

All this happens because the earth is tilted at its axis as it revolves around the Sun. Seasons change on earth because of this. Sun’s angle in the sky throughout the year is caused by Earth’s tilt as it orbits our nearest star.

The solstice comes twice a year. Summer Solstice in the northern hemisphere occurs on June 21, which is the Winter Solstice in the southern hemisphere.

Earth’s axis may be imagined as an imaginary pole going right through the center of our planet. Earth spins around this pole due to which day and night occur. Due to the tilt of the axis, the northern hemisphere receives the most indirect sunlight on December 21 resulting in reduced daytime and a cooler atmosphere. On the other hand, the southern hemisphere gets the most direct sunlight on this day with the longest day and the shortest night.

Ancient civilizations knew about summer and winter solstice. They used to celebrate these days. Our Makar Sankranti which marks the end of winter is a celebration related to changes in the sun’s angle in the sky following the Winter Solstice.