SHORTEST DAY of the YEAR

EARTH TILT(Winter-solstice)

Today i.e 21st of Dec ,is the shortest day of the year in Northern Hemisphere.
It is a day when the Earth's axis tilts the farthest from the Sun and is called winter solstice.

A solstice is an astronomical event which happens twice each year, when the tilt of the Earth's axis is most inclined toward or away from the Sun, causing the Sun's apparent position in the sky to reach its northernmost or southernmost extreme, On the day of winter solstice, North Pole points directly away from the Sun and South Pole points directly towards the Sun, the Sun shines at lowest heights in Northern skies and at maximum heights in Southern skies.

This results in the shortest day in the Northern Hemisphere, but at the same time it's the longest day in Southern Hemisphere.

Winter solstice indicates peak of the cold season. After this, the length of the day starts increasing and it reaches a point where day and night become equal in length at Vernal or Spring Equinox. The day continues to grow longer till summer solstice, the longest day,