^^But the idea of the star already having exploded when Spock launches the rescue mission is an objectionable one: there should be no unpredictable elements remaining, then, and the fate of Romulus should already be sealed at the moment Spock takes off from Vulcan. He knows the speed of the expanding destruction, he knows the top speed of his ship, and if that doesn't allow him to save Romulus, why even bother launching?
If Spock only knows a star is about to explode, then there's an element of uncertainty there, and the mission is worth launching. Also, that way the star can be the homestar of Romulus, which is physically plausible (no FTL waves that mysteriously slow to STL to hit the planet) and depicts a more containable phenomenon.
By the way, how do you get close enough to a supernova to throw something into it?
"It" ought to be a fairly thin shell, through which any starship could punch in a matter of milliseconds. If the solution is to create a black hole in the center of the shell, then Spock could do it to a supernova centered on the Romulan homestar by flying to the Romulan home system.
If the solution is to drop red matter at some random fringe of the phenomenon, though... Then why would Spock pick the Romulan home system for that random fringe? Wouldn't some other fringe be closer in all probability?
This is a very strange star.
It could be a perfectly ordinary star - the strange part is how a black hole can negate or reverse the effects of it going supernova. Or perhaps red matter has some other effects besides/instead of creating black holes?
Incidentally, why is the ship vertical in that image? Wouldn't it be significantly easier to build/modify it when it lays horizontal? Fewer gantries and scaffoldings needed, smaller cranes and a smaller facility overall should suffice, and things should be generally more easily reachable.
Timo Saloniemi