View Full Version : Sector and sub-sector sizes.

Lord Malorne
08-06-2008, 01:45
So just how big are sectors and sub-sectors?

I mean how many systems would they incorporate, has any background detailed roughly the number of systems in a sector? or the number of sectors that exist?

Thanks in advance.

08-06-2008, 03:44
There's are some handy quotes from WD139/140:

Fifty ships is very few when you consider that a typical sector has between 30 and 40 thousand stars forming a cube with sides approximately 200 light years long!

All human-inhabited space is further broken down into sectors, which are most usually cubes of space roughly 200 light years to a side. Each sector is comprised of a number of sub-sectors ranging from ten to twenty light years in diameter, centred on densely populated star clusters, important worlds, or meeting points of various trade routes through the warp. The areas between sub-sectors and sectors - unexplored or uninhabited regions, alien empires, areas inaccessible by the warp etc, - are known as wilderness space or wilderness zones and make up a far greater proportion of the galaxy than that controlled by Humanity.
Some of the more recent 'fluff' somewhat unsurprisingly takes liberties with that.


Lord Malorne
08-06-2008, 09:53
So how many systems would you see in there?

Brother_Chaplian Raimo
08-06-2008, 11:52
Inhabitable? Out of 30-40 thousand, I'd suspect perhaps 10% to be both capable of supporting life and under Imperial control. At most. That's still several thousand, up into the tens of thousands st most.

08-06-2008, 16:52
And then there are the ones uncapable of supporting life, which I'm sure the Imperium operates on anyways for mining or whatever purposes... So I'd say more like 15 or even 20%

Lord Malorne
08-06-2008, 17:28
What effect has terraforming had on these sectors then?

08-06-2008, 22:41
As much as you want it to. Strictly speaking, it is often difficult to swallow some of the worlds and systems described by GW if there wasn't a significant amount of terraforming going on. At the same time? It could be just the 'ole Star Wars approach whereby worlds are described by one environment.

Also, just for the traditional complexity, you might want to note that Dark Heresy (RPG, produced formerly by GW now by FFG) arguably takes some liberties with these earlier values. So, as always, taking everything with a pinch of salt regardless of who is actually doing the telling.


Lord Malorne
08-06-2008, 23:21
So what are the names of ascending steller territories in the Imperium? Like the segmentums are the largest IIRC then I think it goes to sector then sub sector level, but with the apparant sizes of these areas I would have thought sub sectors would be further divided up for command purposes.

Surely there are names?

08-06-2008, 23:43
Well, from the last time that I checked, it was Subsector > Sector > Segmentum. There really isn't anything in between unless CELS from the anargo Sector Project (http://anargo-sector.net/) didn't make up the term "Esquiline Quadrant" when dealing the environs around the Anargo Sector. ;)

Personally I argue for a slightly more organised approach to the political and stellar cartography of the Imperium. Thus the 'size' progression also becomes a hierarchal model for how the Imperium works. Thus the subsector reports to the subsector capital, which then reports to the sector capital. The sector capital then reports to a unit of organisation above that (lets say quadrant for wont of a better term), then another unit above that. Finally this gets to the Segmentum capital and, from there, finally to Holy Terra.

What is reported at the bottom of the chain and what gets recorded at Holy Terra is like, for me at least, one giant version of Chinese Whisphers.

Ain't it cool! :D


Lord Malorne
09-06-2008, 00:02
Agreed :D.

What would you call Ultramar? is that the size of a sector or sub-sector?

09-06-2008, 01:06
What would you call Ultramar? is that the size of a sector or sub-sector?
Ultramar...? That depends. It could be a sector, exists across sectors, or whatever. I'm afraid that my Marine fanboyism is that great at the moment...


Lord Malorne
09-06-2008, 08:51
I have no love for the smurfs I was just using Ultramar as a basis for sizes for SM 'empires' and there relevent sizes.

09-06-2008, 09:56
An average sector, perhaps in one of the western spiral arms where humanity is most dense, can contain tens of thousands of stars and covers an area of 8,000,000 light years. Within this vast wilderness, only a small fraction of systems will have planets and a small proportion of these will be inhabited, or indeed inhabitable. p. 86, BFG rulebook

That volume is based on the 200x200x200 light year cube of space.
From the BFG rule book, there were 81 major inhabited systems of military/strategic importance worth fighting over in the Gothic War. These systems may of course have multiple planets and it is not known how many inhabited minor systems there are in the Gothic Sector but it gives some vague idea of the number of sizable star systems in an average sector. Also if one looks at the spatial map on the inside back cover of the BFG rulebook, one can get a spatial orientation of the Gothic Sector. It is for the most part clusters of stars, with human inhabitation, linked by trade routes, separated by gulfs of empty/wilderness space and nebulas in which pirates, aliens, and renegades can roam.