Winter Solstice 2013

The northern hemisphere winter solstice occurs on 21 December 2013, at 1711 GMT. At this point the Earth’s north pole will be tipped away from the Sun. As seen from Earth, the Sun will stop its slow daily decent south in our sky – over the past six months the Sun’s mid-day height above the horizon has been decreasing steadily – and once again turn north, getting higher in the sky at noon each day, until it gets to its highest point in midsummer 2013.

The actual day of the winter solstice – in this case 21 December 2013 – is commonly known as midwinter, the shortest day, and is the day when the Sun spends least time above the horizon. The further north of the equator you are, the more profound the effect. Indeed if you live within the arctic circle the Sun won’t actually rise today.

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Winter Solstice 2012

The northern hemisphere winter solstice occurs on 21 December 2012, at 1112 GMT. At this point the Earth’s north pole will be tipped away from the Sun. As seen from Earth, the Sun will stop its slow daily decent south in our sky – over the past six months the Sun’s mid-day height above the horizon has been decreasing steadily – and once again turn north, getting higher in the sky at noon each day, until it gets to its highest point in midsummer 2013.

The actual day of the winter solstice – in this case 21 December 2012 – is commonly known as midwinter, the shortest day, and is the day when the Sun spends least time above the horizon. The further north of the equator you are, the more profound the effect. Indeed if you live within the arctic circle the Sun won’t actually rise today.

Winter Solstice 2011

The northern hemisphere winter solstice occurs on 22 December 2011, at 0530 GMT At this point the Earth’s north pole will be tipped away from the Sun. As seen from Earth, the Sun will stop its slow daily decent south in our sky – over the past six months the Sun’s mid-day height above the horizon has been decreasing steadily – and once again turn north, getting higher in the sky at noon each day, until it gets to its highest point in midsummer 2012.

The actual day of the winter solstice – in this case 22 December 2011 – is commonly known as midwinter, the shortest day, and is the day when the Sun spends least time above the horizon. The further north of the equator you are, the more profound the effect. Indeed if you live within the arctic circle the Sun won’t actually rise today.

I’m not that far north, but by most standards I’m pretty far north, in Orkney delivering a midwinter astronomy festival. Orkney sits between 58°41′and 59°24′ North, and on midwinters day the Sun rises around 0905 and sets around 1515, and only spends 6h10m above the horizon. The winter nights in Orkney are long and dark.

But the morning after midwinter, the days will be lengthening. For many cultures then, midwinter symbolised the rebirth of the year, and ancient peoples often built monuments to celebrate the returning of the light.

And people in neolithic Orkney built some of the most incredible midwinter monuments that still exist. I’ll be spending this afternoon inside the 4700 year old chambered cairn at Maeshowe, built so that the passageway – which one has to crawl through to get into the inner chamber – points directly towards sunset on the shortest day.

Maes Howe sections

Given clear skies, the last rays of midwinter sunlight stream into the burial chamber for a few moments before the sun sets.

Maeshowe midwinter sun, Charles Tait

The Orkney poet George Mackay Brown said of midwinter at Maeshowe:

The most exciting thing in Orkney, perhaps in Scotland, is going to happen this afternoon at sunset, in few other places even in Orkney can you see the wide hemisphere of sky in all its plenitude.

The winter sun just hangs over the ridge of the Coolags. Its setting will seal the shortest day of the year, the winter solstice. At this season the sun is a pale wick between two gulfs of darkness. Surely there could be no darker place in the be-wintered world than the interior of Maeshowe.

One of the light rays is caught in this stone web of death. Through the long corridor it has found its way; it splashes the far wall of the chamber. The illumination lasts a few minutes, then is quenched

Winter after winter I never cease to wonder at the way primitive man arranged, in hewn stone, such powerful symbolism.

Dark Skies Orkney – A Midwinter Astronomy Festival

I’m heading up to Orkney for two weeks to run a midwinter astronomy festival. I love Orkney, and the chance to visit there in the darkest of the year is a real treat. For astronomers the long winter nights in Orkney have a lot to offer. It’s not just the relative absence of light pollution above Orkney, but also the fact that in the weeks around midwinter there are over twelve hours of pitch blackness between astronomical twilights.

Aurora over the stones of Stenness

The full programme of events is here, and I hope to blog about a few of my activities too.

The programme is funded by an STFC Science in Society Grant