The Battle of Earth was the climatic outcome of the first rebellion that started the Butlerian Jihad. It was the first decisive victory of the League of Nobles against Omnius and devastated the ancient homeworld of humanity and capital of Omnius Prime.
The battle was a result of Serena Butler, Vorian Atreides, and Iblis Ginjo's return to Salusa Secundus after their escape from Erasmus on Earth. Upon their return the League of Nobles learned of the death of Manion the Innocent at the hands of Erasmus and how that sparked the slave revolt led by Iblis.
As soon as the Dream Voyager arrived to Salusa, the League Armada dispatched its fastest scout. After several weeks, the pilot returned with his terrible report, that only thinking machines remained on Earth. Every single rebel, slave or trustee was dead. At that time, Ginjo was in the interrogation room, and spoke about the concept of the jihad. Since the rebels were motivated by the name and the pain of Serena Butler and would achieve all this, then a coordinated military assault would accomplish much more.
Serena made her plea in the League Parliament that victory over the Thinking Machines was the only way to ensure humanity's survival. The senators questioned the effectiveness of that move, but Xavier Harkonnen proposed to use atomics, a last resort doomsday weapon that had never been used until then. There was no dissent and the proposal formally passed.
In the following 3 months, from their separate space navies, each League World dispatched ships in every kind; munitions factories on Vertree Colony, Komider, and Giedi Prime had worked beyond peak-production levels without rest. Humanity assembled the most powerful, concentrated military force for thousands years.
Just under half of the Armada ships had been equipped with the new Holtzman shield generators due to skepticism and limited time. Xavier had considered waiting for more, but finally decided that further delay would cause greater harm than the installation of extra mechanisms could justify.
Meanwhile, Omnius had dispatched the cymeks to other 'unstable' Synchronized Worlds to suppress any hints of new rebellion.
Swelling with vessels and weapons and countless commanders from planetary defense systems, militias, and home guards, the unified Armada gathered at the orbital launch point above Salusa Secundus. Many of them were armed with atomics enough to sterilize Earth three times over.
Under the command of Xavier Harkonnen and with the help of Vorian Atreides, a human trustee with valuable inside information and machine thinking, the League Armada launched an all out strike against the Earth Omnius. Atreides was not much trusted and had to prove his loyalty to the humans in the battle.
When the armada started bombarding, Omnius Prime launched robotic vessels in a full-scale defensive cordon, as well as his watcheyes to observe all points of view. He ran more than 5000 simulations to determine the correct responses. However the Holtzman shields withstood the first hits, voiding therefore all of Omnius' plans. The first bombers streaked into the atmosphere with their old-style nuclear warheads.
Then Omnius realized he was doomed and sent an update ship carrying a gelsphere with a copy of himself for the other Synchronized Worlds, and orders about the extermination of humans. Atreides was the only one who noticed it and was faced with a grave choice. Having destroyed a dozen of robotic vessels and guarding bombers, he decided to abandon his post, condemning the ships under his protection. Although he risked his (already dubious) prestige towards his new allies.
In the process robotic guns tried to hit the nuclears in the midair however many could get through. At the height of the battle the robotic defenders careened into clusters of kindjals and other unshielded ships (although even shielded ones were destroyed due to malfunctions). The twenty largest Armada battleships hung in stationary orbit, dispatching wave after wave of small attackers. At the same time, five destroyers descended to dump patterns of guided nuclear missiles.
In a last vengeful attack, AI projectiles converged on the ballistas ignoring the smaller bombers and kindjals, they looped back to intercept any evasive trajectories the battleship captains might attempt, and disregarded defensive decoys that were fired to draw the robots off. 11 of the largest battleships were vaporized. Only 8 of the huge vessels (each one shielded) remained. A large percentage of the overall Armada fleet had already been annihilated. The thinking machines eliminated one League vessel after another, but Harkonnen kept sending his fleet forward. Only a fraction of the attacking human force had managed to reach their target points and drop cargo loads of nuclear bombs across the continents.
Meanwhile Vorian intercepted the update ship and board it at the edge of the diffuse cometary halo and managed to disable and board it; there he found Seurat, the robot he worked with when serving the machines. He neutralized him and apprehended the gelsphere.
Then, the atomics detonated; nuclear airbursts generated electromagnetic pulses that scoured the air and surface of the planet. Waves of energy spread, and in a flash obliterated every gelcircuitry network and thinking-machine mind along with Omnius. Planet Earth was completely irradiated and turned into a burnt husk and the machines on the planet were no more.
Of the human fleet, the losses were larger than anticipated however the destruction of Omnius made useless the robotic fighters, making them a short work for the human weapons. Vorian Atreides, considered a coward and traitor for abandoning his post and condemning the bombers under his guard, returned and presented the captive Omnius gelsphere. His action prevented the Evermind to learn the last thoughts, orders and calculations of Omnius Prime, as well as the tactics and new shield technology used by the League and most importantly, the orders to eradicate all hrethgir in the Synchronized Worlds. Corrin-Omnius became the Omnius Prime
The captive gelsphere would provide some benefits to the League intelligence for some years. As for Seurat, he remained in his update ship floating aimlessly in the solar system.
Earth became an uninhabitable lump in space, perhaps never to be inhabited again.
The Battle of Earth was the first engagement of the Butlerian Jihad against the Machines.