Winter Solstice 2015: 'Tis the shortest day!

London: Just like every year, thousands of people descended on Britain's Stonehenge to see the sun rise on the Winter Solstice, the shortest day of the year in the northern hemisphere. 

Some 5,000 people traveled to the prehistoric monument before dawn to celebrate the annual event. After today, the hours of daylight become longer, symbolizing the return of hope. The stone circle in southern England, believed 4,500 years old, is a World Heritage site known for its alignment with the movements of the sun.

What is the Winter Solstice?

The official onset of winter and the beginning of the end for long, dark nights in the northern hemisphere is marked by the winter solstice, which was this year at 4:48am GMT on  Tuesday.

The winter solstice happens because the Earth does not spin upright, but on an axis 23.5 degrees from vertical. As the Earth orbits the sun, it reaches the moment of winter solstice when the north pole is tilted furthest from the sun, making it the shortest day of the year.

The winter solstice is as far south as the sun ever gets, shining directly overhead along the Tropic of Capricorn, 23.5 degrees south of the equator.