There are really only two truly iconic moments in the original Star Wars trilogy. The first is obvious: Luke clutching a lightsaber-cauterized hand stump, clinging to an escapement above a yawning chasm as Darth Vader reveals his parentage in The Empire Strikes Back. The other: A laser-spitting moon hovering above a forest, space ships racing towards it before it can obliterate an entire planet -- the climatic scene of Star Wars.

In the Star Wars universe, Yavin is a giant gas planet, utterly uninhabitable, but circling around it are three habitable moons, the jewel of which is Yavin 4. Covered in jungle-like flora and redolent with the cries of whisperbirds, Yavin 4 is both habitable and remote: The perfect, surreptitious staging ground for the Galactic Rebellion.

Ultimately, though, Yavin 4 is threatened by the very success of the rebellion. When Luke Skywalker and Han Solo rescued Princess Leia from the Death Star, the Empire followed them to the rebellion's base on Yavin 4, in order to wipe it out once and for all. Escorted by a Nebulon-B frigate and two C490 corvettes, the Death Star arrived in the Yavin system and began its slow revolution around Yavin to line up its diminutive forest moon in its site. Every second counted; it was armed with enough weaponry to destroy the base of the rebels just as it had earlier destroyed Leia Organa's homeplanet of Alderaan before her eyes.

Yavin 4's contingency defence plan was desperate: Armed only with a fleet of twenty-two dilapidated X-Wings, eight Y-Wings and two R22 Spearhead Starfighters, the rebellion forces would make a "trench run" along the Death Star's chasmed equator. Their target was a small thermal exhaust -- once reached, it might allow the passage of a single torpedo into the Death Star's innermost core, destroying the station through its hard-to-exploit Achilles heel.

The Rebel Alliance had luck on its side: The Death Star's commander, Grand Moff Tarkin, in a fit of hubris, foolishly refused to deploy the Death Star's TIE Fighter squadrons. Darth Vader alone recognized the threat and ordered his personal fighter squadron to accompany him on a defensive maneuver.

His defense failed: Confronted by his own son's affinity with the force (and the timely arrival of the Millennium Falcon), Vader's exemplary piloting skills were thwarted, and the Death Star was destroyed, spiraling Vader off into space.

The battle's aftermath was significant: Because it had blown up an Imperial symbol as significant as the Death Star, the Rebel Alliance gained open credibility as a legitimate military opponent to the Empire. But this escalated the war. The result was that the Empire began occupying worlds it had previously failed to bother with, leading to the oppression of billions. And since the destruction of the Death Star was so high profile, the destruction of Yavin 4 was secured. The Alliance would ultimately move to the frost planet of Hoth.

Furthermore, when the Empire fell, it eventually decided that a reboot of the Galactic Calendar was in order. The Battle of Yavin was made the reset point, and all dates that fell before it became Before the Battle of Yavin (BBY), while subsequent events were ABY.

There are few moments in Star Wars more meaningful than the Battle for Yavin, either inside its universe or out. Inside the universe, the battle is the point of reference of every major confrontation in the Star Wars sextet. Outside: The image of a Death Star hovering over a jungle moon remains one of the most iconic images of scifi.