the Union was, who was in it,
The
Grand Union, Enlightened Republic/Union, Liberal Union, or simply, the Union is an old alliance of civilizations composed of many Golden and Silver Age nations.
While generally well-meaning, they have this unfortunate tendency to experience massive civil unrest between its members, for a number of reasons.
Not surprisingly, the term "Union" has been turned by some RPers into some kind of jinx.
who in it was anti-Torpal,
While no one is specifically Anti-Torpal as far as I can recall, the vast diversity of political opinion within the Union makes it the likeliest to foster a faction that is both Anti-Torpal and has the firepower to back it up.
Basically, the Union is always just one massive internal conflict away from becoming pretty much anything, politics-wise.
what the Shadow Station was,
The Shadow Station is a highly secretive militarized space station owned by the Shadows. The Shadows are an organization created for clandestine intelligence collection, intelligence analysis and covert tactical response. Originally founded by the Wexxian Avenger - Lord Axon after the Reclamation, the Shadows broke apart from the Wexxian Nation around the time of the Exodus and became their own faction, becoming the sole Wexxians left in the Galaxy until the Tri-Wexxians' return.
The station is hidden somewhere in the galaxy, its location known only to the Shadows. It acts as the HQ and home of all Shadows and Shadows in training. It is also completely self sufficient and capable of housing a lot of stuff.
Other than the cloaking shields, I think it also has a single large offensive weapon for emergencies, though I kinda forgot what it was like other than it operated via the latest Zero Point Technology they had at the time.
A little piece of trivia: The Shadows were originally, and are possibly still, purely Wexxian. However, Jack has stated that other races
might get an invitation if their performance is good enough.
what and where the Galactic Senate was,
The Galactic Senate is basically a space station located somewhere in politically neutral space. It houses the Galactic Senate, a forum created from representatives of numerous races and civilizations.
They create and pass laws which must be obeyed by all members. Examples of issues that were discussed were laws on uplifting, foreign aid and the minimum budget for certain public services.
It's more or less a Space-UN.
There's an off-shoot of this called the Galactic Security Council or something to that effect, though it's not really something of note.
what OP stands for,
Operation.
Operation Unthinkable.Churchill wanted to wage another war just after one of the bloodiest war in history.
and whether we're using blobs or circles, preferably circles?
It's kinda hard to explain using text.
This pic shows it best:

I'll use transparent spheres to achieve the same effect.
As for nebulae, I'll try and see what I can do. Haven't used SE in ages, so I'm still kinda relearning the ropes.