Winter Solstice is today, Saturday. You're as close to the winter sun as you'll ever be. Also, since it's December, look for reflexions off alien ships in the sky, better known as halos. And everyone living North of 66.5 degrees will go dark for 24 hours.

Seven winter images for today's Winter Solstice

1. Diamond Dust Halos, images and montage by Ken Jay, 2008

Is it magic? Rainbow halos illuminate the Matterhorn Peak in Switzerland. This rare occurrence of sundogs and Parry Crystals halos in the sky isn't magic, but not an entirely natural phenomenon either, not as far South as Zermatt. Surreal sky art occurs in the arctic, but on the day Ken Jay photographed the Matterhorn, snow cannons were making snow less than one kilometer away, spraying ice crystals into halos already bearing scientific names.

The Parry arcs were first described by William Edward Parry on April 8, 1820 while his wooden ships were stuck in ice off Melville Island in the Canadian Arctic.

Seven winter images for today's Winter Solstice

2. Rare ice halos at Porsgrunn, Norway, temps - 12C, photo by Mortens Kleiva, 2008

The obvious features are the bright sundogs generated by diamond dustplate crystals, a sun pillar and the almost semi-circular arch of a 22-degree halo. Touching its top is an upper tangent arc from column crystals. At this low sun the UTA curves sharply upwards. It opens up into a gull wing shape as the sun climbs.

Seven winter images for today's Winter Solstice

3. North of the 43rd parallel, the sun doesn't rise very high. North of 66.5, the sun won't raise at all. Image: Ken Tape, via Ethan Siegel. While you're pondering all that darkness, check out Ethan's Top 6 Facts about the year's final Solstice. Amongst them, a reminder about the basics of Earth's journey:

You see, there are two types of year: the tropical year, which we define as 365 (or sometimes 366) days, and is the amount of time it takes the Sun to return to the same position it was in the sky approximately one revolution ago, and the sidereal year, which is the amount of time it takes the Earth to return to the same location in space, relative to the Sun, that it was exactly one revolution ago.

The Winter Solstice cycles through an entire orbit every 21,000 years. Looking at Earth's orbit, combined with the apsidal precession, it means that in about 10,000 years, it will be coincident with aphelion, or the point of farthest distance from the Sun. So Saturday's Winter Solstice is the closest Solstice to the Sun in your remaining lifetime. Ethan also notes that:

The Apollo 8 mission, the first manned mission to reach and orbit the Moon, was launched on the Winter Solstice in 1968, exactly 45 years ago this Saturday. The first humans to ever see the Earth from such a great distance, Frank Borman, Jim Lovell and Bill Anders began their journey away from Earth on the Winter Solstice, the darkest evening of the year.

Seven winter images for today's Winter Solstice

4. First ever images of a Kern Arc

Photographed by Marko Mikkilä in Sotkamo, Finland, 2007. The Kern Arc is the faint upper circle. The lower and brighter part is called a circumzenithal arc.

Seven winter images for today's Winter Solstice

5. The V in the sky

It's not named after "V," it's called the Moilanen Arc after halo expert Jarmo Moilanen of Finland. Photo by by Steinar Midtskogen, Oslo, 2007.

Seven winter images for today's Winter Solstice

6. HaloSim3 software, Image: Halos on Mars simulation by Les Cowley

Photographs of halos could yield important information about what's in the atmosphere on other planets.

You can simulate floating halos for your own fantasy planet where you choose the atmospheric composition — HaloSim3 is available for free. I have not tried it, since I don't think .exe doesn't run on Macs.

It creates simulations by accurately tracing up to several million light rays through mathematical models of ice crystals.
HaloSim3 is the result of a transatlantic collaboration by Les Cowley and Michael Schroeder.

Seven winter images for today's Winter Solstice

7. Night Halos

One must brave the cold to catch this! Photograph by Jari Luomanen, Finland Nov. 2013

[Atmospheric Optics][Starts With a Bang!]