Day of Black Sun


 * This article is about the event. For the episodes, see The Day of Black Sun, Part 1: The Invasion and The Day of Black Sun, Part 2: The Eclipse. For the battle, see Invasion of the Fire Nation.



The Day of Black Sun, refers to a day in history when a solar eclipse occurs when the sun is entirely blocked out by the moon and rendering Firebenders powerless. There have been two known days of black sun in history.

History
Not much is known of the first, other than that it was called "the Darkest Day in Fire Nation History". On the second Day of Black Sun, the Fire Nation Capital was invaded, with the objective of defeating the Fire Lord, thus ending the century long war. However, the Fire Nation was already informed of the invasion, because when Azula, Mai, and Ty Lee disguised themselves as the Kyoshi Warriors to infiltrate Ba Sing Se, the Earth King had (unknowingly) told them about the plan. Because of the Earth King's mistake, the Fire Nation was able to prepare for the invasion. The invasion force managed to reach the Royal Palace, but were unable to escape after the eclipse ended. The invasion force was taken prisoner while the younger members fled on Appa.



The Day of Black Sun was not a total failure, however. It was revealed in the finale that during the eclipse, King Bumi found "the right time to strike" and single-handedly liberated the city of Omashu, thus beginning the eventual liberation of the Fire Nation occupied parts of the Earth Kingdom.

Trivia

 * In the real world, total eclipses have a similar duration time as portrayed in the series. However, the fact that people in the Fire Nation and Earth Kingdom could both see a total eclipse at the same time is quite fictional. The area on the Earth where the moon completely eclipses the sun is very, very small (roughly a few miles in diameter) compared to the area where the sun is only partially eclipsed, which can be as large as an entire nation. That is, unless, the planet where the Avatar universe is located in is a lot smaller than Earth, and/or the moon is closer to the earth, or larger in proportion (making the moon's large coverage during an eclipse plausible).
 * The moon in solar eclipses has no known effect on Waterbending.
 * In Star Wars, "Black Sun" is also the name of the most powerful criminal syndicate in the galaxy.