Hosnian Cataclysm

"Today is the end of the Republic! The end of a regime that acquiesces to disorder! At this very moment, in a system far from here the New Republic lies to the galaxy while secretly supporting the treachery of the loathsome Resistance. This fierce machine which you have built, upon which we stand, will bring an end to the Senate! To their cherished fleet! All remaining systems will bow to the First Order! And will remember this... as the last day of the Republic!"

- General Hux

Thirty years after the Battle of Endor, during their conflict with the Resistance, the First Order destroyed the Hosnian system and, with it, the planet Hosnian Prime, the capital of the New Republic. Its destruction was carried out by Starkiller Base, a superweapon capable of destroying entire star systems. With the destruction of Hosnian Prime came the destruction of the Galactic Senate and part of the New Republic Starfleet. The destruction of the system was visible from around the galaxy, including the planet Takodana.

Though stunned by the events, the armed forces fighting the First Order, commanded by General Leia Organa, immediately began their response. The Resistance successfully destroyed the Starkiller weapon, ensuring it would never eliminate another star system again. However, the extermination of the Galactic Senate and a large part of the Republic Starfleet, as well as the massive loss of life, left both the New Republic and the Resistance in a vulnerable position.

Prelude
"The weapon. It is ready. I believe the time has come to use it. We shall destroy the government that supports the Resistance, the Republic. Without their friends to protect them, the Resistance will be vulnerable, and we will stop them before they reach Skywalker."

- General Hux, to Supreme Leader Snoke

At the end of the Galactic Civil War, the Galactic Empire was left defeated by the New Republic, the government formed by the Alliance to Restore the Republic after the death of the Emperor during the Battle of Endor. The Empire officially signed a treaty, the Galactic Concordance, with the Republic, keeping the remnants of the Imperial confined to their territories in the Core Worlds and the Inner Rim. What remained of the Imperial starfleet, however, retreated into the Unknown Regions and ultimately formed the First Order, a successor force with the goal of destroying the New Republic and bringing order to the galaxy. As part of their plan, the First Order built a fleet in the shadows of the Unknown Regions and constructed a new superweapon called Starkiller Base, one capable of destroying entire star systems. The construction of the Starkiller weapon marked the culmination of efforts by the Old Empire to research dark energy translations and hyperspace tunneling, and it was a successor to the Death Star and the Death Star II superweapons that came before it.

During the conflict that had only just begun to spark between the First Order and the Resistance, Supreme Leader Snoke, the leader of the First Order, considered Luke Skywalker to be an existential threat to the designs of the First Order. Snoke believed that if Skywalker, the last of the Jedi, returned from the exile he imposed on himself after the destruction of his new generation of Jedi and aided the Resistance, a new Jedi Order could arise to threaten him. Kylo Ren, apprentice to Supreme Leader Snoke, attempted to find the last piece of a map that they needed to locate Skywalker, but his efforts at first proved unsuccessful. General Hux, commander of the Starkiller, argued in favor of using the weapon to destroy the Republic and eliminate the government he believed was illegitimate and ill-equipped to lead the galaxy. Hux argued that without the Republic, the Resistance would no longer be a threat. Snoke agreed and gave his permission to fire the weapon.

The destruction of the Hosnian system
"It was the Republic. The First Order, they've done it."

- Finn

On Snoke's command, Hux prepared the Starkiller weapon to be fired against the Hosnian system in the Core Worlds, the capital of the New Republic. When the weapon was ready, Hux addressed the legions of stormtroopers under his command who assembled to witness the destructive firepower of the weapon. Hux promised that this day would be the end of the New Republic and, ultimately, the Resistance, the culmination of everything the troops had worked towards. Hux then commanded that the weapon be fired, and massive beams of energy were fired across the galaxy towards the Hosnian system. When they arrived, the astronomical bodies of the system were destroyed, including Hosnian Prime. With the destruction of Hosnian Prime, the capital planet of the Republic, came the destruction of the Galactic Senate and much of the New Republic Starfleet. The casualties on Hosnian Prime included Chancellor Lanever Villecham and Korr Sella, an envoy from the Resistance sent by General Leia Organa to warn the Senate about the threat of the First Order&mdash;a warning that came too late.

The destruction of the Hosnian system was visible from across the galaxy. The famed smugglers Han Solo and Chewbacca, along with stormtrooper defector Finn, witnessed the system's destruction from Takodana, in the Inner Rim. The sight led to confusion on Takodana, but Finn told Solo and Chewbacca that what they were seeing was the First Order using the Starkiller to destroy the Republic capital.

Aftermath
"The fuel cells have ruptured. The collapse of the planet has begun."

- General Hux, to Supreme Leader Snoke

After the destruction of the Hosnian system, the Resistance put a plan in motion to destroy the Starkiller before it could destroy D'Qar, the world the Resistance called home. Finn, Solo, and Chewbacca were sent to the weapon first to disable its shields, while Commander Poe Dameron led a starfighter assault against the base's thermal oscillator, which contained the energy that it drained from stars in order to power its weapon. The Resistance forces were able to successfully destroy the weapon but at the cost of a number of Resistance lives, including Solo and many starfighter pilots.

Behind the scenes
The destruction of the Hosnian system was depicted in the 2015 film Star Wars: Episode VII The Force Awakens. It was suggested by Pablo Hidalgo, creative executive of the Lucasfilm Story Group, that the reason the blast from Starkiller Base could be immediately seen from Takodana was due to a "hyperspace-rip side-effect" of the Starkiller.

Appearances

 * Star Wars: Episode VII The Force Awakens
 * Star Wars: The Force Awakens novel
 * Star Wars: The Force Awakens: A Junior Novel