Today is Christmas - but this has been a time of celebration for thousands of years pre-dating Christianity.

The winter solstice was officially on Dec. 21. On that day, we have the least amount of daylight all year. To explain the relationship between between the heavens and the Earth we turned to University of Arizona Astronomer Tom Flemming.

Flemming explained the difference between the solstice and the equinox, and explained the significance of the winter solstice.