At Stonehenge in England on the day of the northern winter solstice (always around December 20), people watch as the sun sets in the midst of three great stones – known as the Trilithon – consisting of two large vertical stones supporting a third, horizontal stone across the top.
In 2012, winter solstice for the Northern Hemisphere (summer solstice for the Southern Hemisphere) will take place on December 21 at 11:12 UTC. In other words, it’ll be 11:12 a.m. London Time at the exact time of this winter solstice. Meanwhile, this solstice arrives at 5:12 a.m. CST in the United States.
And so people will be watching on that day – December 21, 2012 – as the sun sets in the midst of the three Trilithon – consisting of two large vertical stones supporting a third, horizontal stone across the top. The great Trilithon faces outwards from the center of the monument, with its smooth flat face turned toward the midwinter sun. In fact, the primary axes of Stonehenge seems to have been carefully aligned on a sight-line pointing to the winter solstice sunset.
What is special about this sunset? The solstice marks the sun’s most southerly point on the celestial sphere, the imaginary sphere of stars surrounding Earth, for all of 2012. So this is sun’s southernmost sunset and thus marks a turning of the year, from decreasing daylight to increasing daylight, for us at northerly latitudes.
This Stonehenge monument – built in 3,000 to 2,000 BC – shows how carefully our ancestors watched the sun. Astronomical observations such as these surely controlled human activities such as the mating of animals, the sowing of crops and the metering of winter reserves between harvests. Stonehenge is perhaps the most famous of of the ancient astronomical monuments found around the world.
When Stonehenge was first opened to the public it was possible to walk among the stones – even climb on them.
The stones were roped off in 1977 as a result of serious erosion. Today, visitors to the monument are not permitted to touch the stones, but, if you go, you will be able to walk around the monument from a short distance away. Visitors can also make special bookings to access the stones throughout the year.
Bottom line: If you stood inside the Stonehenge monument on the day of the northern winter solstice, you could watch the sun set between three great stones, known as the Trilithon – consisting of two large vertical stones supporting a third, horizontal stone across the top. The 2012 northern winter solstice will take place on December 21 at 11:12 UTC, or 11:12 a.m. London Time, 5:12 a.m. CST in the United States.