The Galactic Standard Calendar was the standard measurement of time in the Star Wars galaxy. It centered around the Coruscant tropical year. The Coruscant solar cycle was 368 days long; with a day consisting 360 NET degrees (or 24 standard hours). Numerous epochs were used to determine calendar eras. The most recent of these calendar eras used the Battle of Yavin (i.e. the destruction of the first Death Star) as its epoch, or "year zero": BBY (Before the Battle of Yavin), and ABY (After the Battle of Yavin). The earliest date in the Expanded Universe as a whole is 13,000,000,000 BBY, which serves as the year the universe was created.
The Super Star Destroyer Knight Hammer was destroyed here when it was diverted towards the planet's core after a collision with a rebel vessel.
In the cinematic series
The Rebels established their base in the ancient Massassi ruins found in the lush jungles of Yavin 4 following the abandonment of their previous base on the planet Dantooine. The Galactic Empire sought to use its new space station superweapon, the Death Star, to destroy the small jungle moon and crush the Rebellion. A force of twenty-two X-wing and eight Y-wing starfighters as shown by the Special Edition were sent to destroy the Death Star. With seconds remaining before the moon was to be destroyed, Luke Skywalker, thanks to the timely assistance of his friend Han Solo and the ghostly advice of Obi-Wan Kenobi to use The Force, was able to fire proton torpedoes into a small thermal exhaust port along the Death Star's equatorial trench, thereby destroying the station and saving Yavin 4 from destruction.
All except three Rebel Alliance craft were destroyed in the attack, the only survivors being Luke Skywalker, Wedge Antilles, and an unnamed Y-wing pilot (perhaps Keyan Farlander), and possibly a gunner, making four, not including Luke. The survivors are seen in the film when Luke disembarks his X-wing. Following the Death Star's destruction, a great ceremony was held, during which Leia Organa presented medals of honor to Luke Skywalker and Han Solo.
This battle became known as the Battle of Yavin, and its date is used as a place-marker for events in the expanded Star Wars universe. Events before the Battle of Yavin are marked by BBY ("Before the Battle of Yavin"), and events that occur after are marked by ABY ("After the Battle of Yavin").
The Yavin 4 moon was also the site of giant Massassi Temples built ages ago by the Massassi to worship Naga Sadow, a Sith Lord who had enslaved and mutated the Massassi using Sith Alchemy. The Temple later housed the Rebel Alliance, who used it for shelter and camouflage during their stay on Yavin 4. The Alliance built tall observation towers to monitor entries and exits from their hidden base. The main temple was destroyed during the Yuuzhan Vong occupation of Yavin 4.
In Tales of the Jedi, it is stated that Yavin 4 was where Naga Sadow hid from the Republic in 5,000 BBY and was discovered several hundred years later by the fallen Jedi Freedon Nadd. According to the comic series, the Massassi warriors who built the ruins used by the Rebels were brought to the planet by the Sith Order in its early years.
In the Jedi Academy Trilogy, Kevin J. Anderson suggested that Exar Kun had the temples built. Enveloped in the dark side, Kun elevated himself to the stature of a god. He enslaved the Massassi and forced them to construct an intricate complex of massive temples that were used for arcane Sith ceremonies and rites as foci for the dark side.
In the animated micro-series Star Wars: Clone Wars, Anakin Skywalker has a fierce battle with Asajj Ventress, a follower of Count Dooku. Finally Anakin defeats Asajj, sending her falling down a dark abyss.
Yavin 4 was the base of Jedi Master Luke Skywalker's Jedi Praxeum, where he personally trained the next generation of Jedi Knights. Once Skywalker had trained enough Jedi, this duty was taken up by the married Jedi Masters, Battlemaster Kam Solusar his wife, Chief Librarian Tionne Solusar, as well as another former apprentice of Skywalker's, Streen. The Praxeum was destroyed by the Yuuzhan Vong, during their invasion of the moon in 26 ABY. The Praxeum was eventually relocated to the ancient Jedi homeworld, Ossus. The original Praxeum was the main setting of the Young Jedi Knights series, based on Skywalker's teenage niece and nephew, Jaina and Jacen Solo.
Yavin 4 appears in the downloadable content for the video game Star Wars: Knights of the Old Republic.
Yavin 4 has also been added in the latest expansion (December 2014) of the MMORPG Star Wars: The Old Republic. Titled "Shadow of Revan", the expansion establishes a connection with the previous game.
Since the 1990s, astronomers have discovered numerous extrasolar planets. Many of these planets have masses of order that of Jupiter and so some presumably could resemble Yavin. No extrasolar planetary satellites have yet been discovered because such objects are extremely difficult to detect with current technology. However, both Jupiter and Saturn have large satellites, and Saturn's satellite Titan is enshrouded in a dense atmosphere, so it is quite conceivable that some gas giant extrasolar planets which orbit in their stars' habitable zones could have satellites that could have life or be habitable. One of the most intriguing extrasolar planets is HD 28185 b, which orbits in its star's habitable zone in a circular orbit. However, such planets are currently predicted to be white, with water clouds . Another such planet is 55 Cancri f.
- The New Essential Chronology
- Simon Beecroft, Kerrie Dougherty, James Luceno, and Kristin Lund, "Planet Profiles: Yavin 4", The Complete Locations of Star Wars: Inside the Worlds of the Entire Star Wars Saga (DK, 2005), 13.
- Claire Boobbyer and Peter Pollard, Guatemala Handbook (Footprint Travel Guides, 2002), 323.
- One book, for example, discusses how the "False reports of the discovery of planets outside our solar system, called extra-solar planets, have arisen since..." See Jeanne Cavelos, The Science of Star Wars: An Astrophysicist's Independent Examination of Space Travel, Aliens, Planets, and Robots As Portrayed in the Star Wars Films and Books (Published by Macmillan, 1999), 5–8.
- Yavin Prime on Wookieepedia: a Star Wars wiki
- Yavin 4 on Wookieepedia: a Star Wars wiki
- Yavin 13 on Wookieepedia: a Star Wars wiki