As you may or may not recall, there were two threads regarding the well-known Capella incident. Simultaneously, they degenerated into flamewars between TrashMan and karajorma, and were eventually locked by the latter. However, there are still some questions yet to be answered (namely, mine). The final moments of the two locked threads were based on a conflict between the "Capella was an accident and there was no supernode" school of thought and the "WTF are you talking about" school of thought. In my most expert and esteemed opinion, the arguments for both sides were as follows:
Accident theory/No Supernode
The Shivans blow up Capella purely by accident, as evident from the obliteration of some Sathanases and of the rest of the Shivan forces.
Admiral Petrarch may even have been mistaken when he was talking about a supernode, as he was speculating.
The Shivans are just as fallible as humans are, so they may have screwed up.
The Shivans would be unlikely to screw up at the game's conclusion for no reason at all.
Admiral Petrarch was delivering the game's epilogue, and his words were therefore those of the developers giving us hints.
I may have missed out on some points, but that is unimportant. What matters is that one side believes that Capella was an accident, because Shivans died in the blast. The other believes Capella was on purpose, because there is no reason for Petrarch, delivering the epilogue to be wrong, and Sathanases escaped the supernova via subspace. These, apparently, are completely irreconcilable positions.
Why can't it be both ways?
Petrarch was closing the game. The supernode is the only canon explanation for the destruction of Capella. It's all we have. Why would they lie to us in the epilogue? Equally important, if they were creating a supernode to go home, how could they fail so spectacularly, wiping out many of their own ships? There is an explanation that reconciles this contradiction, but bear with me for a moment. It is important to recall that the Shivans had an entire armada of specially-built node-constructor ships. This is tried-and-tested technology. There is only one way to explain their failure. Remember that the Shivans have such a huge impact on us because of their amazing technology, including the ability to travel through unstable jump nodes. How unlikely is it that the Shivans messed up their own tech all by themselves, at the game's conclusion, no less! How anticlimactic would it be if the terrifying Shivans simply had their machines blow up in their faces? There must have been an outside reason for the spectacular malfunction. That reason was the GTVA.
Throughout the Second Shivan Incursion, the GTVA fights the Shivans tooth and nail. Arrogant, incredibly so, but not without reason. The Shivans win only through unstoppable numbers and pure, brute force. Heavy casualties are sustained by the Shivans, up to and including a Sathanas juggernaut. Only the arrival of multiple juggernauts is enough to break through GTVA defenses and secure a system. There is no doubt that the GTVA was at least a thorn in the Shivan side. Remember, the GTVA is the only possible factor that could have affected the Shivans. No other races other than Terrans and Vasudans are known to exist. Assuming
wasn't going to pull something out directly out of its rectum for FS3, only the GTVA could have done it. The GTVA must have done something right. In response to my original post, ngtm1r suggested that it could have been the destruction of Shivan transports by the GTVA in Their Finest Hour. This is possible, but when considered from a story perspective, is extremely unlikely. The destruction of a few transports in the same mission as the death of the Colossus was what caused the subspace wave to fail? What about something far more visibly important: the first Sathanas? Here, we have a reason for the supernova. A compelling one. The only GTVA victory in the entire Second Shivan Incursion, a campaign marked by one success, followed by crushing futility. Perhaps the only success was enough. One nodebuilder ship, taken out of the equation, may have been enough to destabilize the subspace wave, allowing the star to go supernova and only a few ships to escape.
Think about it. We can take Petrarch as reliable, so the Shivans built a supernode. The Shivans wiped out part of their fleet, presumably in the attempt to go home, so there must have been some sort of failure. The one factor affecting Shivan operations that we know of is the GTVA. The one GTVA success happens to have been the destruction of a Shivan nodebuilder. This timeline makes perfect sense in terms of story. There's no anticlimax, and every event has a cause. What other conclusion can be drawn?