On the December solstice solstice, we celebrate the (unofficial) first day of winter in the Northern Hemisphere and first day of summer in the Southern Hemisphere. Unofficial? Yes. Winter and summer start at the solstices by tradition, not official decree. Yet these solstices bring very real occurrences to our sky, which you can witness for yourself.
Happy solstice, everyone. The December solstice will come tomorrow at 23:03 Universal Time. At this instant, it’ll be at 5:03 p.m. for the Central U.S., or around sunrise for North and south America, sunset for far-eastern Asia, midnight for Africa and Europe, and noontime over the Pacific Ocean. We in the Northern Hemisphere will have our shortest day and longest night of the year. And yet – if you consider the word day in another light – the longest days of the year come each year in December for the entire globe.
Awesome news! A Laysan albatross named Wisdom – said to be the world’s oldest known, banded, wild bird at an estimated age of 63 – has been photographed (December, 2014) incubating her newest egg. Go, Wisdom! Still breeding at 63!
Here is a 16-image panorama of the Milky Way arced above a little known area in northern Arizona – called White Pocket, in the Vermilion Cliffs National Monument. Those with a four-wheel drive vehicle can see this spectacular landscape of twisting Navajo sandstone.
The outreach team of NASA’s MESSENGER spacecraft has organized a competition to name five impact craters on Mercury. Submit your ideas before January 15, 2015. Names chosen as finalists go to the IAU for selection of the five winners. Details inside.
The annual Ursid meteor shower always peaks near the time of the December winter solstice, so, in 2014, look for some possible activity over the next several nights. This shower favors the more northerly latitudes in the Northern Hemisphere, but even at far northerly latitudes, it’s generally a low-key production, not nearly as exciting as the Quadrantids in early January.
Those who admire the shape of a Christmas tree might like to know that its shape has evolved in response to wind, snow, and light.
The Northern Cross isn’t as famous as its counterpart – the Southern Cross – visible from the Southern Hemisphere or the northern tropics. But the Northern Cross also looks like a cross, and it’s pretty easy to spot. It’s a large, noticeable star pattern.
The star Deneb marks the top of the Northern Cross, and the star Albireo marks the bottom. Tonight you can find the Northern Cross shining fairly high in the west at nightfall, as seen from mid-northern latitudes. It sinks downward during the evening hours, and stands proudly over the west-northwest horizon around mid-evening.
The Northern Cross is what’s known as an asterism. In other words, it’s not a constellation but simply a noticeable pattern of stars. It’s part of the constellation Cygnus the Swan.
On December 3, 2014, satellite images revealed a large iceberg – measuring about 165 square kilometers (64 square miles) – east of the southern tip of South America in the South Atlantic Ocean. This iceberg doesn’t meet the criteria for tracking or naming. NASA Earth Observatory said:
Only icebergs that have a side measuring at least 19 kilometers (12 miles) long are named and tracked by the U.S. National Ice Center. That means nearly round or square icebergs—like the one pictured above—can be quite large and still not meet the criteria for naming and tracking.