This Week’s Night Sky: Winter Solstice and a Christmas Moon
Celebrate the shortest (or longest) day of the year, and check out the holiday season’s best celestial events.
On the flip side, December 21 is the longest day in the Southern Hemisphere. At this time of year, Earth’s northern axis is slightly tilted away from the sun, so the Northern Hemisphere receives less sunlight and experiences winter, while the Southern Hemisphere enjoys summer.
The exact date and time of the winter solstice always fall around December 21, but shift slightly from year to year because of the difference between a calendar year of 365 days and the solar year of 365.26 days: the exact time it takes Earth to make one trip around the sun.
It’s amazing to think that despite the two celestial orbs appearing so close in our skies, Mars sits nearly 15 light-minutes from Earth, while Spica
