The following is me nitpicking.
Dekskull wrote:A dead galaxy makes a lot of sense thematically. Both because the Tyranids may have munched through it already (maybe leaving some of their organisms behind, frozen in the wastelands of dead worlds, AND/OR the old ones never went to Andromeda.
Well, the Old Ones not showing up probably wouldn't result in a dead galaxy. One with fewer habitable planets due to a lack of terraforming and with less sapient life, certainly. But I'd think that the ingredients for spontaneous generation of life would probably be present in all galaxies unless there's something I don't know. Like, if only one in a million planets is Earth-like, a galaxy with billions (trillions?) of planets should still statistically happen to have a few of them. And that means there's a chance the planet is in the process of producing living organisms.
Now why would anyone want to go there if all the planets are dead? My guess would be there are still resources worth exploiting. Also with the great rift and tyranid hive fleets approaching, a general sense that the Milky Way may be done for.
Those reasons are still a bit tricky though. Sure, an entire galaxy probably has some cool gasses and metals that
40k's factions would like to have access to, but that's a heck of a trip to make to gain access to them. Even using an especially stable and "fast" warp route to get to them, you're ultimately still just dumping some colonists and ships into a new sector or two. Which you could already do in the Milky Way. So for mining to be the motivator, they'd have to be finding something absurdly valuable to justify the trip. Like, so valuable that suddenly having access to it would probably let one faction win the war in the Milky Way.
And if it's just people having a sense of dread, well, which people exactly? Some imperial noble who would functionally have to give up most of his wealth and power to try to establish a new colony? And who could conceivably be accused of cowardice/treason/sewing fear in the population by doing so. Really, no one in the guard or ecclesiarchy could easily try to run away to a new galaxy without it being seen as a punishable sign of weakness/lack of faith. But a random peasant in the 41st millenium probably doesn't have the resources to attempt such a trip either. So what population would hit our sweet spot of wealthy/powerful enough to use a bunch of ships to found at least one new colony in a new galaxy but also not so high profile that such an attempt would be nipped in the bud?
Also something to think about. What would the level of warp energy in the new galaxy look like? I would think it would be a lot less than the Milky Way which seems to be overflowing since the great rift. Maybe psychic abilities are more difficult in Andromeda? That would make navigation and astro-telepathy even more difficult, but also would be harder for chaos to summon demons and what not. So maybe people see if (rightly or wrongly) as a safe refuge from chaos?
Good question. My guess would be that, assuming distance from the Milky Way actually matters at all, the warp would be relatively calm, similar to how it was before the War in Heaven. Not sure if a "calm" warp means it's harder or easier to work with (Psychic Awakening suggests harder), but it would probably be a lot
safer. A psyker could theoretically call upon larger amount of warp power without having to worry about a daemon suddenly eating him.
Working in the other non warp races could be tricky, but not implausible. Maybe we get some 4th Sphere Expansion Tau, now somewhat deranged. Dormant tyranid infestations, and Necrons...well because they're necrons. Maybe they found the "Andromeda gate" a trillion years ago and then went to sleep.
This does seem to be one of the bigger hurdles if you want to bring all the
40k factions along. The aeldari use the webway rather than actual warp travel, and the webway doesn't seem to really extend beyond the galaxy (although
Ghost Warrior raises questions). So space elves would probably be out. 'Crons being outside the galaxy would mess with some of their existing lore. The Silent King leaving isn't really a big deal if he's basically just sailing off to visit his summer home in another galaxy, and the dynasties seem awfully concerned with beating each other up over territorial disputes if they could just head off to another galaxy where they wouldn't have to share.
In any case, you all are right. Any product expansions could fit right in with the Milky Way (its got like what, 3 trillion stars in it. Plenty of room lol). But I thought a new galaxy would still be cool. (Mostly because I feel like the galactic "map" is feeling a little crowded right now). Darn maps!
I find it helps to remember that any icon you see on a map is really,
really inflated so that the features they're drawing your attention to are more readable. Some maps show Iybraesil as being in Terra's neck of the woods, but the distance between them is vast enough to hold as many different stories and scenarios as you want. Every patch of light on the map could have as many wars and bits of history tied to it as Armageddon, and the dark patches between that dot and the next one could hold even more.