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Christmas morning, seen from space


This visualization shows a hemisphere's worth of weather on Christmas morning as seen by the GOES East satellite. The weather data is overlaid on a "Blue Planet" image of the Americas.

All calendars must end, whether we're talking about the Maya calendar's nearly 400-year baktun cycle — or our 25-day Cosmic Log Space Advent Calendar. This final image for the 2012 calendar comes from the GOES East weather satellite, and shows how the weather is shaping up this Christmas morning in the Americas.

The GOES satellites, East and West, are in geostationary orbits 22,300 miles above Earth. That allows them to monitor a whole hemisphere's weather 24/7 from a fixed position above the the planet. (GOES stands for Geostationary Operational Environmental Satellite.) NASA takes the GOES satellites' readings on cloud cover and overlays them on a full-disk "Blue Planet" view of the oceans and land masses. The result is a hemisphere-wide snapshot of Earth like this one, produced every three hours.

Although this picture marks the end of our Advent calendar, you can keep the satellite images coming throughout the next year with GeoEye's free desktop calendar. The calendar consists of a series of computer desktop wallpaper images, highlighting GeoEye satellite views from the past 13 years. DigitalGlobe also offers 2013 calendar packages with an Earth-from-space theme, for purchase through the company's online store.

Seeing our planet from space tends to broaden a person's perspective on Earth's problems and preciousness: That's what Apollo 17's astronauts discovered 40 years ago this month when they snapped the first and most famous "Blue Planet" picture. Here's hoping that the past month's pictures of Earth as seen from outer space have broadened your perspective as well. Have you seen 'em all? If not, graze through the links below.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other science and space news coverage, sign up for the Tech & Science newsletter, delivered via email. You can also check out "The Case for Pluto," my book about dwarf planets and the search for new worlds.