SG-1 devised a plan to destroy Apophis's fleet by creating an artificial supernova. With the evacuation of the Tok'ra base on Vorash, the entire solar system orbiting Vorash's sun would be devoid of life. SG-1 took the opportunity to use Vorash's stargate to dial P3W-451, the planet being drawn into a black hole, and launch the stargate toward Vorash's sun. The gravity of the black hole removed enough stellar matter through the stargate to disrupt the balance between the forces of fusion and gravity in Vorash's sun, thus creating a supernova which obliterated the entire solar system. Apophis's fleet was destroyed, but the two motherships of Apophis and SG-1 escaped by entering hyperspace during the massive explosion. However, the force of the supernova threw both ships far off course, sending them over four million light years away, far beyond the galaxy. At maximum hyperdrive speed it would have taken 125 years to return. Modifications to one ship that were later made by the Replicators allowed it to exceed the maximum speed and return home.
Cross Reference: Apophis, Black Hole, P3W-451, Vorash
Episode Reference: Exodus