Behold! A year has passed since the great Mayan apocalypse of 2012 — newsflash: we’re all still here — and the winter solstice is again upon us. The solstice marks the shortest day of the year for dwellers in the Northern Hemisphere, and the longest day of the year for those south of the equator. But that doesn’t just mean darkness will cast a great shadow over the Northern Hemisphere. Leading up to the solstice, the sun’s highest point appears closer to horizon each day, which means the days get shorter and the nights get longer. During the solstice, the sun’s position relative to Earth seems to pause (solstice means “stationary sun”), and from that day forward appears to inch northward, meaning more sunlight for those of us in the north. Here’s a look at why you should care about today’s astronomical event.
What is it?
The 23.5 degree tilt in Earth’s axis of rotation creates a rise and fall appearance of the sun over the course of a year. During the winter solstice, the Northern Hemisphere is pointed at its furthest distance from the sun, bringing less light and colder temperatures. The winter solstice occurs at a specific time, not just day. This year, at 12:11 p.m. EST on Saturday, Dec. 21, the sun shone directly over the Tropic of Capricorn, the farthest south the sun reaches. In the Southern Hemisphere, it was the longest day of the year.
So then what happens?
After the solstice occurs, days grow longer for north of the equator, as the sun appears farther above the horizon. This movement culminates in the longest day of the year on June 21.
Is it related to Christmas?
Sort of. There’s no date in the Bible specifically pointing to Dec. 25 as the birth of Jesus Christ, so some experts believe the Christian church selected the date several centuries later, tying it to the Roman holiday Dies Natalis Solis Invictus, or the Birthday of the Unconquerable Sun. The winter solstice serves a turning point in many cultures, which is why it was tied to the Mayan apocalypse scare that marked the end of the calendar and to some believers, the end of the world.
Just how short is the day?
North America will only see nine hours and 32 minutes of daylight during the solstice, and 14 hours and 28 minutes of nighttime. But the winter solstice doesn’t always happen at the same time. Next year northern dwellers can brace for the solstice at 11:03 p.m. In 2015 it will occur on Dec. 22.
What are other important dates for the sun?
The summer solstice occurs on June 21, the longest day of the year in the north. On March 21 and Sept. 21, Earth’s equator passes the center of the sun, which are known as “equinoxes.” These two dates mark the point at which hours of day and night are nearly equal.
This post has been updated for clarity.