The Milky Way Galaxy in 30K/40K

[Deus_Ex_Machina]

It is said in the Rogue Trader book (1987) that only a tiny section of the Milky Way galaxy has been discovered and settled by mankind. Most of those worlds have even lost contact with Terra. And yet whenever I visit the setting of 30K/40K I feel it to be confined and restrictive almost but obviously not as bad as the Old World. This may be because most of the novels and publications deal with the same enemies of mankind. This even caused me to place my HH 2.0 campaign into the Andromeda galaxy where I felt there is more freedom, a blank slate if you will, to introduce new factions (e.g. Rust Bots and more to come) into the game without conflicting with the current lore. 

 

A recent read of the Rogue Trader book mentioned Rogue Traders leaving the Milky Way galaxy and never being heard from again. Is this a missed opportunity to come up with stories from visitors or returning Rogue Traders from other galaxies? A few months ago I bought the trilogy Forges of Mars (Graham McNeill; 2012-2014) and it turned out to be an adventure story of an Imperial fleet going onto a crusade into uncharted galactic territory. This was a breath of fresh air as the run-of-the mill 40K story boils down to a planetary invasion of Xenos XYZ and the Imperium has to deal with it in one way or another. 

 

Do you think it needs to be this way because Warhammer is a wargame and therefore needs to have lots of easily identified xenos as enemies in comparison to having more adventure stories in the spirit of Star Trek?

[phandaal]

Depends on the stories. Some are good at developing a sense of scale, others have their characters show up whenever and wherever they need them.  Sandy Mitchell, Dan Abnett, ADB, Peter Fehervari, Anthony Reynolds, Edoardo Albert, and plenty of other authors have done good work in showing the scale of the universe. Seems to work best when they drill down to a "small" portion of the galaxy and focus on that so you can see how big even a single solar system is.

 

I have used this number many times before here, but the Milky Way contains between 100 and 400 billion stars. Assuming the low end, and assuming the Imperium's million worlds are spread over a million solar systems, that means the Imperium in the 42nd millennium controls 0.001% of the Milky Way galaxy.

 

This is partly why I dislike it so much whenever the story makes claims about weapons or events that will wipe out the entire galaxy. Or when everything ties back to the Great Rift, etc. When the actual scale of the unimaginably vast Imperium is tiny in the grand scheme of the galaxy, powering that scale up to be 100,000 times larger than the entire Imperium makes it large enough to be absurd if you think too much.

 

As for why the scale of the galaxy seems way smaller sometimes, it is probably just like you say. The company needs to showcase the factions they sell, and they want people to place their battles into the context of whatever location they have, and they want people to use the characters they are selling. So you end up with all of the stories at least one aspect of that. You do not hear about the 10,000 year war going on between two undiscovered alien civilizations right around the corner from Terra, although with the actual scale of the galaxy that could definitely happen.

[MARK0SIAN]

As Phandaal say, I think Abnett in particular does a very good job of giving you an impression of the scale of the galaxy and the imperium, in particular his Ravenor/Eisenhorn series. They’re one of the few ones I’ve read where travelling between planets/systems genuinely takes months. 
 

The change of the setting from a sandbox to a storyline has definitely made the setting as a whole feel smaller for me. Having the great rift span the galaxy naturally means a lot of stuff happens with reference to it and if locations all over the galaxy are dealing with the same thing it’s naturally going to make it feel like the imperium is a more cohesive and centralised system than it actually is. 
 

I think you’ve essentially just got to ignore the main setting and make up what you want for wherever you are. The easy excuse for why there’s no imperial presence somewhere is that the imperium has only ever travelled where the light of the Astronomican can reach. There’s no reason there can’t be a planet or star system close to terra covered in a small but perpetual warp storm that has always made the astronomican invisible and therefore it’s devoid of human presence. 

[Adeptekon]

The Galaxy for Mankind is kinda like Army Ants claiming the earth for themselves.

[Felix Antipodes]

The Imperium’s claim of a million worlds is designed to impress the uneducated masses, to whom it sounds massive because they don’t understand the true scale of the galaxy.

In my headcanon the Imperium is like the Pacific.  A bunch of island clusters separated by vast distances.  These “islands” are connected by Warp routes that cross vast territories where the Imperium has very little presence (but claim it anyway).  Well populated regions like Segmentum Terra and Ultramar may not have very many connecting Warp routes linking them directly (possibly why the 13th Legion was delayed by the ruinstorm during the HH).

[Adeptekon]

12 hours ago, Felix Antipodes said:

The Imperium’s claim of a million worlds is designed to impress the uneducated masses, to whom it sounds massive because they don’t understand the true scale of the galaxy.

In my headcanon the Imperium is like the Pacific.  A bunch of island clusters separated by vast distances.  These “islands” are connected by Warp routes that cross vast territories where the Imperium has very little presence (but claim it anyway).  Well populated regions like Segmentum Terra and Ultramar may not have very many connecting Warp routes linking them directly (possibly why the 13th Legion was delayed by the ruinstorm during the HH).

Right. I mean it could be that our galaxy at present is embroiled with unending conflict between a million worlds and we'll never see it because we're sheltered somewhere off in a spiral arm of the galactic country side.

[kabaakaba]

It seems to me that when the GW spoke about a million worlds, they themselves had a poor idea of the size of the galaxy, because according to current data the galaxy consist of more than 400 billion stars (and most likely there are even more). So imperium controls 2,5e-6 or 0,0000025 of galaxy... It's the same as saying if I own an acre of land, then I control France.

Edited July 30 by kabaakaba

[calgar101]

I think the 1 millions worlds tag line is artistic license as well as a little misunderstanding the size of the Milkyway? 

Rule of cool over sense so to speak

Edited August 1 by calgar101

[SimonRaele]

I always assumed the Imperium stretched across the entire Galaxy,  but did not control every aspect of it, leaving millions of star systems if not more, not under their control.    Especially when you take into consideration  Ghoul stars,  Dead star systems, and places that might still be completely hidden on the galactic map.  Its also realistic as tens of millions to hundreds of millions of stat systems might not have habitable worlds on it.  Or im thinking to deeply, and its as simple as, the light does not reach to this system there for it does not exist deal.

[Adeptekon]

It does make me wonder if another imperium of long maned apes is coming for us.

[Iron Lord]

On 7/30/2026 at 5:47 AM, kabaakaba said:

It seems to me that when the GW spoke about a million worlds, they themselves had a poor idea of the size of the galaxy, because according to current data the galaxy consist of more than 400 billion stars (and most likely there are even more). So imperium controls 2,5e-6 or 0,0000025 of galaxy... It's the same as saying if I own an acre of land, then I control France.

Could be that GW subscribe to "only a minuscule proportion of star systems have a planet worth inhabiting by humans"

 

The Rogue Trader FFG book inflates the number of stars even more:

 

As powerful as it is, the Imperium does not rule the entire galaxy. Mankind’s worlds are spread thin across the 200 trillion stars that make up the galaxy. 

 

I think they might have copied Epic Armageddon's 200 billion figure and accidentally changed it to "trillion":

 

 

As powerful as it is, the Imperium does not rule the entire galaxy. Mankind’s worlds are spread thin across the 200,000,000,000 stars that make up the galaxy. Within the Imperium’s vague borders are rebellious enclaves of human worlds, domains ruled over by alien war leaders, colonies of creatures too aloof or basic to disturb Mankind or draw the attention of the war fleets. 

 

 

And the Deathwatch FFG book, while simply saying "hundreds of billions" acknowledged that "a million" is minuscule and that the habitable worlds not controlled by the Imperium vastly outnumber those that do:

 

 

The Imperium of Man is spread across roughly two thirds of the galaxy and consists of more than a million inhabited worlds. Although a huge number of planets, this is nothing when compared to the hundreds of billions of star systems in the galaxy. The Imperium is therefore spread extremely thin across a vast volume of space; its worlds are dotted through the void and divided by hundreds, even thousands of light years. The Imperium cannot therefore be thought of as a coherent territory which extends across the galaxy and has discrete borders. Mankind shares the galaxy with countless alien civilisations, many separate Ork empires and vast areas overwhelmed by the Tyranid Hive Fleets or corrupted by Chaos. None know what secrets lie between the stars. Undoubtedly there are other advanced civilisations, lost human colonies and the ruins of long dead races waiting to be discovered and explored.

 

 

The "400 billion stars" figure goes right back to 1e.

 

 

The galaxy contains some four hundred thousand million stars various types. Of these only a fraction are presumed to have habitable planetary systems, and only a fraction of these have been investigated.

 

Even the human-controlled Imperium, by far the largest and most widely distributed of all stellar empires, contains only a tiny fraction of the galaxy's stars.

Edited August 2 by Iron Lord

[kabaakaba]

Well, that doesn't change the fact that the Imperium is absurdly small. I can't remember which codex it was in, but there's a map that shows the Imperium on one side and the Ork proliferation on the other. And from this map, it's obvious that the Orks rule the galaxy. Not the Imperium.

[Adeptekon]

"It is my dream. An Imperium of Man that exists without recourse to gods and the supernatural. A united galaxy with Terra at its heart."

-- The Last Church

[SimonRaele]

One thing I  did notice, or well it is my assumption.  even if you started at year 0   42,000 years is  not enough time to colonize 1,000,000  worlds.   considering  humanity didnt really start traveling at great speeds till what 18 millennia?   if we take into consideration the notion of humanity already having colonized most of the planets the  Emperor launched his crusade to recapture.  what 50 to 100 planets every year would need to be colonized to make that number - and thats if we count the age of strife.   (if we count the idea that we didnt colonize during the Crusade.) or again maybe m looking too deep,  I prefer this ambiguity to time constraints, makes lore easier to wiggle around certain concepts.

[Karhedron]

1 hour ago, SimonRaele said:

One thing I  did notice, or well it is my assumption.  even if you started at year 0   42,000 years is  not enough time to colonize 1,000,000  worlds.

 

I have put this down to exponential growth. Not all of those planets would have been colonised directly by Terra. If you start of with just one planet and it colonises one planet per year, then each colonised planet then colonises one planet per year, you get exponential expansion. You would actually reach the million worlds total after only 30 years.

 

Obviously it would take years (or even decades) before settled planets to launch their own colony ships to other planets but it shows that humanity could easily have reached 1 million worlds just during the DAOT.

[SimonRaele]

Well if we go by Exponential growth yes,  its a outright snow ball that can't be stopped.    Though id assume the reason its not  hundreds times the amount of planets based on that. is logistics and  the ability to control that many planets all at once, even with AI.    Not to mention  the need to explore first and research planets to be able to colonize.  

[Adeptekon]

That Golden Age tech did it in 10k years.