That means that for half the year, the north pole is tilted a bit toward the sun (and experiences summer) and that for the other half of the year, the south pole is tilted a bit toward the sun, giving the northern hemisphere winter. So, when is it in 2017, how long will the day be, and what does it mean? The time and date of the solstice change slightly each year, but this year's solstice occurs at 11:28 a.m.
Today, the winter solstice, marks the first day of astronomical winter.
For more than 4,000 years, Stonehenge has stood like a Neolithic sundial, marking the longest day of the year and the shortest - taking aim at the sun like a giant stone gunsight.
Of course, our long winter night pales in comparison with Alaska, where the sun barely climbs above the horizon for three to four hours in much of the Last Frontier.
Christians celebrate the birth of Jesus Christ on Christmas Day, December 25th, when we decorate our homes and communities with lights and stars to welcome the birth of the "true light of the world".
What is the winter solstice 2017? Why is today the shortest day of the year?
He explained that the sun gradually lights the chamber over five days, peaking today on 21 December.
Noontime shadows on Thursday will be longest for those of us in the Northern Hemisphere because the sun doesn't rise as high in the sky. Sunrise was at 8.03am GMT and sunset is at 3.53pm.
The Winter Solstice doodle features an animated mouse ice skating above a mouse hole with what appears to be collected food for hibernation.
For thousands of years, people have taken part in rituals to mark the occasion.
People flock to Stonehenge to celebrate the winter solstice every year What happens at Stonehenge on the winter solstice?