PBS Space Time Season 2015 Episode 21 The Calendar, Australia & White Christmas

PBS Space Time season 2015 episode 21 titled "The Calendar, Australia & White Christmas" explores the history and science behind the modern calendar system, the astronomical significance of Christmas, and how the concept of a "White Christmas" varies across the globe.

The episode begins with an introduction to the history of the calendar system, highlighting its evolution through various civilizations and cultures. The Gregorian calendar, which is commonly used today, was introduced in 1582 and replaced the earlier Julian calendar. The Gregorian calendar is a solar calendar based on the Earth's orbit around the Sun, and it consists of 365 days in a common year and 366 days in a leap year.

The host of the show, Matt O'Dowd, explains how the calendar system is used to mark important celestial events such as solstices and equinoxes. These events have significant astronomical and cultural importance, and they are celebrated by many different cultures and religions around the world. One such event is Christmas, which is celebrated on December 25th and has its roots in both Christian and pagan traditions.

The episode then explores how the concept of a "White Christmas" varies across the globe. In Australia, for example, Christmas falls during the summer months, and it is not uncommon for people to celebrate the holiday on the beach or have barbecues outside. In contrast, in countries like Canada and the United States, a "White Christmas" is often associated with snow and cold weather.

The host explains how the Earth's tilt on its axis and its orbit around the Sun affect the changing seasons and the position of the Sun in the sky. He also discusses how these factors contribute to the differences in climate and weather patterns across different parts of the world.

The episode concludes with a discussion on the future of the calendar system and its potential changes. As the Earth's rotation gradually slows down due to tidal forces from the Moon, the length of a day is getting longer. This means that the current calendar system may become inaccurate over time, and adjustments may need to be made to keep it in sync with the Earth's rotation.

Overall, "The Calendar, Australia & White Christmas" is a fascinating exploration of the history and science behind the modern calendar system, as well as the significance of important celestial events and cultural traditions. The episode provides a thought-provoking look at how different cultures view the changing seasons and climate patterns, and it encourages viewers to consider the interconnectedness of our planet and the cosmos.