Today is the December Solstice, the first day of winter in the northern hemisphere. The new season officially began at 5:30 UTC, that is 12:30 A.M. Eastern Standard Time.
The tilt of the Earth’s axis, a 23.5 degree angle, is what gives us the seasons. Today, as winter begins, the northern half of the Earth is tilted away from the sun. This position brings the northern hemisphere the least amount of the sun’s energy all year.
Today is also the shortest day of the year. Since the summer solstice in June, the arc of the sun’s daily passage across the sky has been dropping toward the southern horizon. It stopped today at the Tropic of Capricorn, its southern most position. (The word “solstice” is Latin for “sun stand still”). It will now begin its apparent journey northward and our daylight hours will gradually increase.
Marking the transition to longer days, the winter solstice has been a cause for celebration across many cultures throughout history.
Image Credit: scijink.nasa.gov