The Winter Solstice came today, December 21st at 7:04am. But what the heck is it? I kind of knew what is was but for all of you like me who wanted the exact description here it is.
As the Earth travels around the Sun in its orbit, the north-south position of the Sun changes over the course of the year due to the changing orientation of the Earth’s tilted rotation axes with respect to the Sun. The dates of maximum tilt of the Earth’s equator correspond to the summer solstice and winter solstice, and the dates of zero tilt to the vernal equinox and autumnal equinox.
So basically it is when the sun is at its greatest distance from the equator. In the Northern Hemisphere it occurs when the sun shines directly over the tropic of Capricorn.
The winter solstice marks the first day of the season of winter and is the shortest day of the year.