Structure of the Galaxy: 6 Questions Confirmed

[AotrsCommander]

Summary: I am looking to confirm a few things on the structure of the galaxy as we know it to make sure I have a credible enough understanding for a sci-fi project I'm working on.

Background to question: For my sins, I make sci-fi starships and ground forces wargames models as part of my day job. Over the last year, I have been pushing out the attached lore (mostly on SpaceBattles). On the literally two people who have actually said anything, they have asked for a sort of map.

Now, unfortunately, this has proven to be a fundementantally impractical task. Essentially, being kneecapped by having an atypical Understanding Of Scale and an inherent desire to Get The Details Right (being engineering-trained) even if no-one other than me actually cares if, say, the ramps for alien!space!IKEA are the correct gradient to push a trolley up or not.

("How bad could it be?" you ask. Let me put it this way - the universe itself it has about, ooh, thirty years of history and at one point I went through every source I could find and plotted up a thousand (*checks* no, 1200) locations (which steadily ticks up over time) from, like, 50+ currently known factions (a non-exhaustive list) over two sections of the galaxy, wherein the majority of the noted locations are habitably planets (with a notably lack of commonly-known stars). Even accounting for a precursor retrocausally-probability engineered artifically-inflated number of earth-like habitable planets, conservatively these sections of the galaxy would contain *millions* of star systems. And the geography does not even simplify into a top-down map like say, something like BattleTech manages, because said locations would be positioned in 3D space and in highly factionalised territory, not be a neat contiguous series of borders but a morass of interconnected lines. The latter being caused by the FTL transit methods are not contrained by fixed "jump-points" or like the like, with only some nominal soft-locked optimal (100% safe) departure points at local (2 million km, essentially "battlefield" levels) so it being functionally impractical to "block" expansion. It's even more complex than that, but that's even less relevant to the question.)However, I have been looking at ways to do even a crude, not-to-scale, highly inaccurate but possibly illustrative scribble map. Even this looked like it was impractical, until I read the Honor Harrington book series and the maps there gave me a rough idea of how I might proceed.

I am looking today at making a pass at that. I will be using my CADs package for ease, plus to start with, I think I will need the infinite canvas and the utility of a third dimension, even just using somewhat absracted planes.

(Now, it did occur to me that I could, *in theory,* using something like a 1mm to a light-year put a sphere down for every star... If I could do it as fast as 1 per second for eight hours per day every day for the next 171 years just to cover the 1800 000 000 real stars - which is OBVIOUSLY not practical, unless I could find a conveniantly-formatted and labelled .stl or .dxf file or something within my budget (£0) to bootstrap on. And if that would not present so much information as to be fundementally unreadable anyway. So that is really not going to be worth attempting.)

However, before I embark on what is fundementally the most [cigarette]packet attempt at relative positioning, I want to make sure I have my google-researched understanding of the structure of the galaxy is reasonably solid, which brings us to my actual questions, and making sure I have indeed correctly grokked what I've read.

My understanding then, is as follows. Please correct any errors or now-outdated understanding. (Most of this information is derived from google and/or wiki reading, which is likely suitable enough for non-specificallt-scientific standards, but I still like to be as right as I can be.)

(I am labelling the direction perpendicular to the plane of rotation in the anticlockwise direction as "up." (Or "galactic north.") With other directions being "spinward", "anti-spinward" and "coreward" and "rimward.")

1) The 1.8 billion stars (of the projected 100-200 billion) on modern star maps are only the ones that Earth has observed and are thus inherently, tending to be the brighter ones; even within observable distances, some will too dim to be seen from Earth and this becomes more true the further from Earth you go. (Which is why the number of stars and shape of the galaxy is still estimated.) Obviously, in the immediate vicinity of Earth, we can be pretty sure there's not any barely visible stars hidden, but I'm not entirely clear at the point it starts to get hazy. My tentative understanding is also that if you go out reasonably far, even Sol-brightness stars become too dim to see from Earth, but I would definitely appreciate being corrected if this is in error.

2) The arms of the galaxy are not discrete entities, but more like ripples in the disk, and there space between the arms is not entirely empty void, but contains a less dense number of stars (or at least a lower proportion of brighter, observable (younger?) stars).

3) The galaxy is about 100 000 light-years in diameter, but about 1000 light-years thick (except for the core bulge, the dimensions of which I don't think I've seen an estimate for. However, that region is sufficiently far from the area I'm looking at it probably doesn't have too much bearing anyway. Very tentatively, the bulge would especially towards the core be more unsuitable for terrestrial life habitation due to the higher concentration of radiation emissions...?)

4) Sol (and thus Earth) lies (well, strictly, oscilates around) more or less in the "middle" of the galactic disk's cross-sectional thickness (i.e. near the plane of rotation). It is also slightly more than half-way along the galactic radius from the core (orbiting circa 54% of the proposed maximum radius).

5) At the "rim" of the galaxy, it is less again a discrete "stop" of stars, but stars (and clusters) will become less frequent and peter out into the halo of old, globaluar star clusters which may or not have retrograde or highly inclined orbits compared to the modal stars of the galaxy (which orbit anti-clockwise).

6) Binary and trinary stars comprise the vast majority of star systems, but are possibly less likely to have planets (or at least (human-)habitable planets) simply due to the additional gravitational complexities et al (?). But if 85% of star systems are binary-plus, this logically still means a lot of planets in such systems and potentially more planets around those than singular stars overall. (I freely admit I am not necessarily up-to-date on how many exoplanets have been identified or projected and what sort of stars they are around.)

Have I go about roughly the shape of it at that, or is there any other pertinent factors that I have missed (particularly with regard to the context of the issue I'm looking at)?

 

[jedishrfu]

One could do something like this sci-fi map:

https://images-wixmp-ed30a86b8c4ca8...Q.6YNV5EJs_WnyfNATwS54uuOs148MyeesdAtdouv2ufw

or this map of the stars around us:

http://cdn.eso.org/images/screen/eso0303c.jpg

 

[DaveC426913]

As far as scale goes, have you considered a logarithmic scale?

I assume you have more data near Sol and less far away. So the scale could match that.

This is not the right diagram, but it makes the point.
Left diagram is linear scale, right diagram is same data on a logarithmic scale:

Here's an actual logarithmic polar template:

 

[AotrsCommander]

I assume my knowledge on galactic structure was corrent, then?

One could do something like this sci-fi map:

https://images-wixmp-ed30a86b8c4ca8...Q.6YNV5EJs_WnyfNATwS54uuOs148MyeesdAtdouv2ufw

or this map of the stars around us:

http://cdn.eso.org/images/screen/eso0303c.jpg

The former is exactly the sort of map I can't do; I did look at that sort of thing when I was first asked about it, but gave it up as a bad job just because I couldn't even get started. There are a) WAY more factions b) they don't even cover the whole galaxy c) it's not got a third dimensional component. Basically, you can't get the right information on that sort of map, it's too simplified (and That One Picture Of The Galaxy that the artist has used as a basis isn't a big enough to be able to zoom down to an appropriately right bit. Analogously, it would be like trying to draw, I dunno, a map of the UK counties and/or cities when all you have to work with is a globe map.

Second map also wouldn't really work at the scale and complexity involved, I don't think off the top of my head, but I'll bear that format in mind as another potential way to represent the 3D element. (You might, dubiously, be able to do something like that with the map I did come up with, but I am not sure whether it would help the complexity much.)

The thing is, I'm not creating a map from the whole cloth, I'm having to back-work 30 plus years of lore into a map and try and make it fit, makng the whole thing so much harder than if I was just making it up new from scratch. I feel it something analogous to trying to make a map of the Star Trek universe, by which I mean, "situating every planet-of-the-week" not the general "quadrant" maps. (Now, I'll grant you, someone might have actually done that in the years, but it would not, I suspect, be a short endeavour.)

What, after six hours of effort, I managed yesterday was about the best I'm going to get (as it was even harder in practise than I feared) and I eventually forced myself to simplify down to ovals and through out anything more elaborate as just eating too much time for the gain. (Which is, thanks to Facebook screwing up the image and then not letting me edit or replace it, thus far, four likes...)

I sort of got somewhere using essentially five planes for a 3D element.

Really, all this does (and can do) is approximate the relative positions of the (Aotrs-)local powers to each other and a very broad-and-entirely not-precise idea of territory size.

https://photos.smugmug.com/Primary-Gallery/i-jNvZTR4/2/4ba1b330/X3/Galactic Scribble Map v1.0-X3.jpg

This doesn't not even cover everything by long margin (it excludes a lot of independant worlds, system states or powers with only a handful of systems) and I just threw up my hands on trying anything more elaborate with human space, given how disperate and factional humans. The FTL in predominant use does NOT have the apparently-these-days more typical fixed jump points, meaning expansion during colonisation from a factionalised planet like Earth (or, the other side of the galaxy, the Elenthnar species' Haron-Urrot pair) is less a border and more a furry mass of join-the-dots lines between individual star systems that can and will intermesh (especially after wars and independant planets).

(Humans space has also believe it or not been SIMPLIFIED by the recent creation of the GTSR which straight-up absorbed lots of the mid-sized or smaller Earth-N-adjacent human powers.)

I think it fair to say this universe is less a story than a history, which brings it with it all the mess and morass and lack of conveniance history has.

As far as scale goes, have you considered a logarithmic scale?

I currently have no intentions of even attempting to put a scale in at all (logarithmic or otherwise), since trying to match that to existing data would simply be extremely impractical without spending hundreds of hours trying to do it and the aformentioned having to have an accurate star map to start from* to even get the base assumptions right. (Distance between systems has always been noted in transit time, where applicable, not distances explictly because of how impractical it is to make a map of so many systems.) It would likely be a project in and of itself, unfortunately and there's a limit to what time I can afford to take out of my day job to do it. (Especially as from the lack of reception so far from the lore generally, I would probably be the only one that would care anyway, but I either do a job Right or I don't do it.)

(Most of the powers on that scribble map are classified as "major powers" which has a size of "typically fifty to hundreds or more" systems with the expectations that the latter ebnd if the more suspected; the most concrete of the powers is the Army Of Red Spear which notes it has 26 inhabited worlds under its control; and what that means in their stated context is fundementally equivalent to "fully, densely populated species homeworlds**" as opposed to just "a planet that has been colonised" and doesn't cover colonies or outposts etc, and the Aotrs is unusually smaller for a Major Power because of other reasons that let it punch well above its weight. It probably still has low hundreds of systems, colonies and bases etc on top of that.))
*Worth noting that would even itself is not a total solution, since Earth-N on this map is not Earth-E (this one, in the Orion Arm) and aside from a a probably 100 light-year radius around it where the stars are likewise mirrored, but I would still need to use the current star data to work from to position Earth-N correctly and then start filling in the blanks. It is not, as they say, a straight-forward job like drawing a map for a campaign world or something, which is why I've had so much trouble with it.

**For the sake of arguement, they are know they are cheating by counting the planet Myst among those number, since while it was technically once one of those it isn't now, but they apparently decided that as it did because of the ridiculous strategic importance of something found in the ruins there, but that's going into FAR more detail than is relevant for here.

 

[DaveC426913]

I assume my knowledge on galactic structure was corrent, then?

It kind of poses the obvious question: since your end goal is canon-derived in the extreme (i.e. dictated by the fiction), trying to make it also physically accurate seems both unnecessary and headache-inducing, no?

https://photos.smugmug.com/Primary-Gallery/i-jNvZTR4/2/4ba1b330/X3/Galactic Scribble Map v1.0-X3.jpg

Do the zones represent physical spheres of influence? ("spheres" in quotes)

The Raarg'Ssth seem to have a very strong preference for expansion along a particular axis and a very strong aversion along the perpendicular. Is that a story-driven fact, or is that an artifact of the diagram visualization?

 

[AotrsCommander]

It kind of poses the obvious question: since your end goal is canon-derived in the extreme (i.e. dictated by the fiction), trying to make it also physically accurate seems both unnecessary and headache-inducing, no?

That's why I'm NOT attempting to do it and presenting a scribble-sketch (with noted limitations) as a rough guide.

I wouldn't even be attempting that, but the literally only two people that have said anything to me on the couple of hundred thousand words I've put out said "why is there not a map?" (to which I replied initially "because it's fracking near impossible to draw one") so I have been doing what I can to present some sort of spatial representation.

(I mean, I literally argued that Full Thrust (the game), Star Trek and Star Wars (or even *slight shudder* 40K) fundementally have not had maps or maps of any distinction for deacdes of their existence (if ever) and that didn't really seemed to matter, but...)

As to why astrophysical accuracy is important to that... Because I like to get things as close as possible to Right before I go anywhere else. (Hense literally working out the angle of ramp for alien!space!spider-robot!IKEA trollies. Heck, my literally first thread on this forum some years ago was doing astrophysics calculations for a world, which I have since applied to many others.) I will be damned before I don't Do My Research to the best of my ability.

(Yes, this means this stuff centred around the arguably point-of-view of nation composed of magical space liches appears in practise to be harder sci-fi than a lot of space opera. It is what it is. You'd have thought that would have gotten some points for novelty, but apparently not.)

I mean stuff like understanding that the space between galactic arms are NOT just empty space, like, kind of important to know, because otherwise some of this would be even more difficult when trying to do it all AND also confine it to a tube.

Do the zones represent physical spheres of influence? ("spheres" in quotes)

Relative position to each other and very, very broadly and inaccurately, approximate size of territory (in relation to each other).

The Raarg'Ssth seem to have a very strong preference for expansion along a particular axis and a very strong aversion along the perpendicular. Is that a story-driven fact, or is that an artifact of the diagram visualization?

Raarg'Ssth territory is long and ribbon-like. It would actually be quite a bit more wavy than that, but this was one of the points that makes this hard.

(Saivali space is also a bit long and thin, but they're right up again the rim for the most part without any close neighbors of any size, so I could do them as a circle without straing so much; the Raarg'Ssth had to be represented that way.)

"Raarg-Ssth space is a relatively ribbon-like domain, narrow and long but deep, reaching from a little corewards (near the Jalyrkieons and Vivarathk) all the way towards the galactic southernmost reaches of the Japanese Empire. This places their upper reaches some distance "below" the Royal Elven Kingdoms. The coreward end of the territory bulges out a little more, and this is where the Raarg'Ssth homeworld Prarg is located."

For that matter, Vivrathk territory is quite irregular in practise, going more rimward and southward than coreward and northward, but again, trying to get something vaguley like it as an approximation was just implausible to do without being able to actually hang things on a proper framework which just isn't practical.

Both groups are about the same age as Earth-N as FTL capability, but they both happened to be closer to the core, which meant their expansion was more hampered by the Strayvian Empire (the arguably largest galactic super-power until about a hundred, hundred-and-fifty years ago situated more corewards on the top of this map); the Jalyrkieons (and the rest of the Lyrokanas - "Jalyrkieon" is equivalent to "Terran" in context) and the Acrodinians were both Stryavian vassals (among others). The Lujuqujul are from an isolated cluster and are a lot younger as an FTL species, but they also have got a bit of a step up by salvaging old Dominion tech.

(The Strayvian DOMINION invasion corridor was the nasty surprise a few years ago for the humans of the now-Soviet Remnant when the believed-dead Stravyians turned back up.)

The Raarg'Ssth in particular's lateral expansion otherwise has thus been either blocked-in by other powers as well as determined by whether or not there's any suitable systems to expand into. (Path of least resistance and all that.)

 

[DaveC426913]

That's why I'm NOT attempting to do it...

OK, I must have read too fast or something then. I could have sworn your OP was specifically asking for details about accuracy of galactic structure.

(I mean, I literally argued that Full Thrust (the game), Star Trek and Star Wars (or even *slight shudder* 40K) fundementally have not had maps or maps of any distinction for deacdes of their existence (if ever) and that didn't really seemed to matter, but...)

There a very good reason why that is so, and in each case you mention, you can bet the creators of those worlds all came to the same conclusion about not doing so.
See, it's one thing for a third party or fan to try to make sense of the shape of space as canon describes it - it's entirely another for the creators to do so.

Were the creators to do so, that would make it canon, and thus would handcuff them to storylines that fit in the the world. That's bad. It's hard enough to write a good story without having somebody quote from the Bible saying "The FilbertFlangers and the GrappleGrommits are a hundred light years apart. A wounded shuttle could never make that journey. The premise of your story is impossible."

But if a fan made the map, the creators have no obligation to honour it, leaving them without constraint.Being vague about world-spanning maps is a time-honoured tradition in multi-author fiction.That is not to say you - a third party - can't or shouldn't attempt it, but it is not a short-coming of fiction franchises for its absence; it is strategic.

 

[AotrsCommander]

OK, I must have read too fast or something then. I could have sworn your OP was specifically asking for details about accuracy of galactic structure.

It was. Just because I am not attempting the task of physically placing every star in order to do the map accurately doesn't mean that I don't need to understand the basis I'm standing up from. As I said last post, going from an incorrect understanding makes everything else wrong down the line.

"Why do you care?"

Because it matters.

Just because I don't know the answer doesn't mean there is no answer, just one that I don't know yet. Just because I don't have a few spare centuries to do the job properly (now) doesn't mean that I don't want to the job to BE ABLE to be done properly (maybe one day).

Maybe most people would be satisfied just slapping down a ramp on a floor plan and calling it a day, or just saying "this planet is tidelocked and sometimes the sun does funny things," but I want everything I do to be as solidly, plausibly anchored as I can manage. Expansion up FROM reality, not replacement for it.
(I have not gone into the more esoteric details of this because I didn't feel it was especially relevant to the specific thing I'm looking for (and this is all complicated enough as it is), but for one other reason, one of the conciets is that this is not all happening in some alternate universe, but being presented to the people of Earth-E (i.e. this one) as an explanation of what is happening out there right now.

(The explanation of Why Multiple Earths is even longer and more complicated, so I won't even try here, but for the sake of arguement, it's here along with everything else.))

 

[DaveC426913]

Just because I don't know the answer doesn't mean there is no answer, just one that I don't know yet.

True, although the other side of that coin is that it is possible that there is no solution. Your canonical data may already contain impossibilities. Shouldn't stop you, but also shouldn't surprise you.

 

[AotrsCommander]

True, although the other side of that coin is that it is possible that there is no solution. Your canonical data may already contain impossibilities. Shouldn't stop you, but also shouldn't surprise you.

One of the reasons I have explictly never defined FTL speed is that it then WOULD mandate a distance component which would be nonsense until I actually could calculate things correctly (which is a task I realized would be impractical even when I first started DMing and/or writing scenarios); so there's almost certainly enough wiggle room for stuff that had listed times between (and even those are subject to potentially some wiggle due to rounding), if it ever does comes to that and I have something of an innate talent for work-arounds.

The closest I have come to defining FTL transit speed is that the absolutely top power can cross the galaxy in "hours" (and actually gets faster in intergalactic space) and no-one else is even near that, though FTL is pretty quick compared to a lot of sci-fi. (Since while I sometimes use game stats to inform things when writing the lore and units, I am always very careful to say that any set of rules is merely an imperfect simulation of the "real" world and thus not absolutes, since the real world is vastly more complicated.)

(For instance, when noting starships weapon capabilities, I quote an "accuracy envelope" which is definitively NOT range (while it is informed by the absolute range by the game statistics I use for game play purposes), but is the point at which the weapons are considerd to no longer be able to reliably hit a target moving at a significant fraction of the speed of light.*)

But, all that said, I still have to understand what it is I'm abstracting. Which is where physics and such comes in. People have said that one needs to understand the rules of writing before one breaks them; my approach had been to always at least try to understand the physics before I break them, or at least be able to offer a plausible explanation as to why physics is broken or at very least show I've at least spent more than five minutes thinking about it.

(How do Aotrs railguns attain faster than light travel speeds if they don't have infinite power? How do coldbeams (which shoot the privative of heat, not its absence) work, especially in space?)

Even if it's magic, I DO have to explain it, or bare minimum show willing to try in good faith. That's important. And if I get it wrong, I can at least go "yeah, it's wrong," but then attempt a better, more accurate explanation.

(This is, in fact, why the attendant lore is written, essentially, "in-character" - you can 100% blame Stewart Cowley's Spacecraft 2000-2100AD for that - instead of being omnicient fact, since it does allow room for Bleakbane to be, like, wrong in reporting what he knows. But like any good scholar, Bleakbane tries his best to get it right and make corrections when he can.)
*While making evasive maneouvres, a target which is just flying straight might as well just be a static target whatever speed it is at.

 

[DaveC426913]

you can 100% blame Stewart Cowley's Spacecraft 2000-2100AD

Ah yes. I've worn the ink off the pages of my copy.

 

[AotrsCommander]

Went into my head as a child, I think even before I could read (it was given to my Dad a year before I was born) and never left.

I can genuinely say that is unquestionably the most influential piece of literature I've ever been exposed to.

 

[DaveC426913]

I can genuinely say that is unquestionably the most influential piece of literature I've ever been exposed to.

For me it was this:

I was thirteen, and a budding artist.

 

[snorkack]

The closest I have come to defining FTL transit speed is that the absolutely top power can cross the galaxy in "hours" (and actually gets faster in intergalactic space)

This is plausible - and has implications.
It is plausible to have FTL which is relatively slow inside galaxy, because it is slowed down by dodging stars and their gravity fields, and faster in outskirts of the galaxy with less stars to dodge.
But it won´t be just rim which is a logical routing. The galaxy is a three-dimensional object - a disc.
How do you call the surface edge regions of the disc in north and south?
Obvious routing to speed up travel and have less stars to dodge is to travel some distance out of the disc to north or south, then along but outside the disc to next to your destination, then back to the disc.

 

[AotrsCommander]

That's fundementally the reason for their increased speed in intergalactic distances, yes, stellar gravity wells impinging on (this type) of hyperdrive, which is basically just a super-dooper-refined version of what is arguably the most common*. (Though the faction(s) in question don't tend to venture out that way too much, as the local galaxy had more than enough problems. And when one of the did last time, they ran out of Reality entirely.)

The increase in speed would be largely negliable close enough for the galaxy to make popping in and out worth it (intergalactic distances being another two orders of magnitude or so larger on average); by the time you'd gone out far enough to get a significant speed increase and come back, it'd be quicker to just have gone there directly.
*There are a number of various FTL technologies in use, so to some extent it varies.

 

[snorkack]

While there are 13 constellations in zodiac, there are 27 in Milky Way:
https://en.wikipedia.org/wiki/Galactic_coordinate_system
The poles of Milky Way are in Coma Berenices and Sculptor.
Coma Berenices cluster is about 300 ly from Sun, and therefore Milky Way plane. How much emptier is Milky Way seen from Coma Berenices cluster?

 

[AotrsCommander]

I'm sorry, I'm not terribly sure I'm following your post.

Constellations are so Earth-centric (and Earth-E centric at that in my specific instance) that they are fundementally meaningless to what I'm looking at. (Likewise, the galactic co-ordinate system, while useful to know about, is Earth (-E) centric and thus wouldn't be meaningful to, like, any of the powers on my map.)

I'm further puzzled by Coma Berenices, since on a google, it says this is a constellation and the stars (et al) which compose it are between 30 and 2600 light-years, which does not qualify as a cluster (according, again to wiki, which suggests both sorts of cluster are no more than about 30 ly in diameter). Did you mean the Coma Star Cluster which appears to be a cluster within Coma Berenices?

I have some trouble, I'm afraid, fitting right ascention to galactic longitude and thus getting which direction, but I THINK the 12h right ascention puts it off to the "left" (as if looking at the galaxy from "top-down"), and it is only 25-ishº up and at only circa-300ly away is still pretty close to the middle of the galactic (both vertically and horizontally), so I imagine the view can't be much different in terms of visible stars. Unless that location puts it outside the local arm(s), but I'm afraid I'm at the part that without a 3D graphical representation (the exact sort of thing, I like, can't do for the lore stuff in question), I have honestly no clue, sorry.(Again, let it nt be said I don't at least make an attempt at Doing The Research, even on a slightly-non-sequitur forum post question...)

 

[snorkack]

I see. "Earth-E" and "Earth-I" are off the map, and Earth is "Earth-E".
From viewpoint of Earth-E, "corewards" is in Sagittarius, "rimwards" in Auriga, "spinwards" in Cygnus and "antispinwards" in Vela. Which means that the constellation boundaries are, roughly, sectors converging on Earth-E.
They don´t have meaning for the non-human factions, but how about humans? Alaska-Canada border is longitude 141 west of Greenwich, across rivers and mountains, and both sides comply with it. Even though it is a round number of degrees west of Greenwich, not Washington or Ottawa, thus meaningless to both sides.
Yes, I meant Coma star cluster as "Coma Berenices cluster". So it should be fairly close to Milky Way North Pole - near Earth but out of the densest part of the disc. I wondered how much emptier the region is - it is a visible object, concentration of stars, potentially of planets, yet in a region potentially of smoother space otherwise. For one thing, what is relevant is the relative scale of the distances along disc vs. across disc. How far is the map three-dimensional and how far is the setting actually two-dimensional because the regions/factions extend through the effective thickness of the Milky Way disc, with irrelevant wilderness north and south of the disc? And irrelevant for what? Settlement, or also travel?

 

[AotrsCommander]

They don´t have meaning for the non-human factions, but how about humans? Alaska-Canada border is longitude 141 west of Greenwich, across rivers and mountains, and both sides comply with it. Even though it is a round number of degrees west of Greenwich, not Washington or Ottawa, thus meaningless to both sides.

Given that the Harbinger Retrocasual Probability Engineering that created the multiple Earths (and Haron-Urrot pairs and the quite possible theorhetical other species aside from humans and elenthnars that got that special treatement no-one has found yet) only mirrors (i.e copies) the local region of up to about 100 ly,* and the significant distances between the Earths, it is almost a certainty that the constellations of each Earth will likely fall into the "differences in mundane details" factor. Now, Harbinger Probability Engineering is robust enough that there remains a possiblity that the constellations might be very close in appearence when viewed from an individual Earth (at least as far as something as broad as astrology goes), but the stars that compose the constellations will not (cannot, in most cases) be the same (in if in the apparent same spot when viewed from Earth); and the further out one goes from "major details" the fuzzier the differences do get.

Thus the galactic co-ordinate system would have been likely developed on -N as on -E, but likely would have fallen quickly out of favour (with anyone NOT from Earth-N) as being humanocentric. (Especially a point of note that the Aotrs are effectively the viewpoint nation, NOT humans and they absolutely wouldn't use it.)

Yes, I meant Coma star cluster as "Coma Berenices cluster". So it should be fairly close to Milky Way North Pole - near Earth but out of the densest part of the disc. I wondered how much emptier the region is - it is a visible object, concentration of stars, potentially of planets, yet in a region potentially of smoother space otherwise. For one thing, what is relevant is the relative scale of the distances along disc vs. across disc. How far is the map three-dimensional and how far is the setting actually two-dimensional because the regions/factions extend through the effective thickness of the Milky Way disc, with irrelevant wilderness north and south of the disc? And irrelevant for what? Settlement, or also travel?

Without a better an accessible map of the galaxy's known stars to try and place it all, exactly how far away this all is from Earth-E is somewhat conjectural, which also makes it hard to hazard density, so I have to rely on the assumption that the region is likely within or partly within an arm (or arms), though most likely quite a bit further outward than Earth-E is given that the powers known are all generally closer to the rim than the core. (One reason there's less powers towards the bottom of that map.)

The map is otherwise three-dimensional in terms of covering the 1000-light year depth of the disk; the Aotrs are basically on the "top" of the disc, and the Vivrathk are quite close to the "bottom."

(The Aotrs military capital world is located in a fairly isolated portion of space towards the "top," surrounded by a lot of very same-y stars, which grants its exact location not completely certain outside that power, and further more the only approaches to it would be through Aotrs territory or a dangerous trek up outside of the disk, where an attacking fleet would be... Effectively as obvious to sensors even at FTL transit modes as a light in a dark room against the void. (Even assuming you could even stay in an extra-dimensional FTL like hyperdrive the whole time and not have to drop into normal space, e.g. if you had teleport drives.) Which places it, if not the actual top of the disk, at least the local top or close to it, given of course the boundary is hazy anyway as the amount of stars peters out. That said, it could also just be on a local "edge" or the periphery of an arm oir something, too.)

But that thickness factor does, on typing this post out, give us some level or order of magnitude of the map scale that I'd not considered, since the horizontal spread is going to be wider than the vertical, so you could easily be looking at the map covering something on the order of two to five or even ten thousand light years roughly square (the lower estimate apparently suggesting my guess of at-least millions of stars (50 million around Earth-E at that distance, assumption of approximately or more similar density on this map) was fairly on the mark. I'd actually say it was probably closer to the larger end; even a 10k light year-square area would represent only about 1.5% of the galaxy's volume (assuming a constant 1000ly thickness and counting the non-halo area as 90kly diametre) And billions of stars...!

(Though at that, the number of habitable worlds doesn't seem bonkers, even with a significant artificial inflation by the Harbingers. Based on the 3 billion (observable) stars from Earth-E google suggests are within 10kly, which in the absense of anything else is a plausible guess: If my 1200 canon locations are only 1% (or even 0.1%) of the occupied stars, i.e. those that have any sort of occupied presense at all, even if it's just a solitary deepspace watchpost, that's still only one system in 2500 with anything in it. (I don't think we yet know what proportion of stars actually have exoplanets, do we?) That's room for a lot of wiggling...)

Notably, most of the powers in this region are fairly centrally located and have only been expanding towards the rim ("up", "down" or outwards) comparitively recently, and the rim has a lower proportion of useful stars (i.e. ones with planets, or useful planets, at any rate). And in general, those few powers with sufficiently advanced FTL tech to comfortably take long trips without worrying about supply issues to use the empty space as transit routes generally don't NEED to.

(Fixed "jump-points" do exist, in the form of the occasional wormhole or natural hyperspace gate (et al), and while not required for FTL transport also are quite important, as controlling one is significantly better in cutting transit times than going outside the disk. Which explains why both the Herosine Empire and Saturn Syndicate Ascency*** have both gone to great lengths to keep mum about the ones they each found.)

That said, the ever-present omnicidal Cybertanks may be an exception, since they very well could use the "outside" of the disk to widen their throw-away-attack-fleetranges and that might even explain why they are occasionally encountered so far afield.

The Saiyvali have not been fully gone over, so it's possible they might as well.

The Extra-Galactic Aliens, well, the name says it all, but it is possible they have some sort of staging ground actually outside the galaxy as well, but with their stealth technology, it would be quite hard to spot.Edit: First-order magnitude calculation if the top-end power can cross the galaxy in, say 20 hours, that makes them traveling at a speed of 5000ly/h, which if I have done my calcs right, suggests an effective FTL speed of 5.4^11 c, which is... Quite a lot faster the maximum quoted speed for the Culture. And this is why our dear point-of-view nation of magical space-liches regards them with tantamount to abject terror.

Ah heck, let's make a REALLY ball park calc and say that if it took something six months to cross the map at 10k (which is likely quite slow to do so), that comes out at a respectable 13440 c. In practise, it's likely a lot less than that, given canon-noted transit times tend to hover around weeks, though obviously not all the way. (Of course, speed doesn't necessitate ease of deployment of fleets; it according to google might only take around a week for a modern navy to cross the Atlantic, but that doesn't mean that you can deploy a war fleet that quickly; the transit time would be likely coming towards the least of the temporal factors to get a fleet on station!)

*However, this has been measured from the point of view of Earth-N and Earth-F, based (someone predictably) from the larger-influential Earth-N where the differences between it -N and-F and most notable. Earth-E is known, but sufficiently far (and in a very isolated bit of space (as you haven't seen many ships pass laterly, have you?) that it has no official contact with any of the major powers**. So there has not been a direct comparison to ascertain how MUCH of the area around -n and -E is actually mirrored and it amy or may not be more than the 100ly thus far observed.

**The author of the Guide Bleakbane, was ostencibly the laison to Earth, but active only under the clause of plausible deniability on the internet, and actually there to keep an eye on a (formerly) stable wormhole that led between that Earth and Aotrs space in case of the remote chance of something coming through from outside. Indeed, that Bleakbane would himself not know how far Earth-N is from Earth-E is entirely plausible, because it is only the existence of the direct wormhole that has allowed the Aotrs to find it. The wormhole was further only large enough to basically let him come and go from the Aotrs side via using Gate XXV, a 30th level spell with some reasonable inter-planetary range, though the wormhole made that a very short "hop". (If it wasn't, the Aotrs would have likely made their presence very publically known when they showed up with a starfleet...!) So he has, functionally, no basis for comparison himself aside from the data I could likewise find on the internet of Earth-E.

***Who are clearly not transparently a direct homage to the aforementioned spacecraft 2000-2100AD's Terran Trade Authority in name, technology and apperance...!

 

[snorkack]

(The Aotrs military capital world is located in a fairly isolated portion of space towards the "top," surrounded by a lot of very same-y stars, which grants its exact location not completely certain outside that power, and further more the only approaches to it would be through Aotrs territory or a dangerous trek up outside of the disk, where an attacking fleet would be... Effectively as obvious to sensors even at FTL transit modes as a light in a dark room against the void. (Even assuming you could even stay in an extra-dimensional FTL like hyperdrive the whole time and not have to drop into normal space, e.g. if you had teleport drives.) Which places it, if not the actual top of the disk, at least the local top or close to it, given of course the boundary is hazy anyway as the amount of stars peters out. That said, it could also just be on a local "edge" or the periphery of an arm oir something, too.)

Notably, most of the powers in this region are fairly centrally located and have only been expanding towards the rim ("up", "down" or outwards) comparitively recently, and the rim has a lower proportion of useful stars (i.e. ones with planets, or useful planets, at any rate). And in general, those few powers with sufficiently advanced FTL tech to comfortably take long trips without worrying about supply issues to use the empty space as transit routes generally don't NEED to.

If the FTL travel depends on resupply on friendly and equipped planets then the trade routes would route around wider gaps.

in a fairly isolated portion of space towards the "top," surrounded by a lot of very same-y stars,

resembling the Coma star cluster, just a different cluster?
If listening to FTL noise is a defence against hostile navies, but it is hampered by the clutter in the disc, then it makes sense that legitimate trade and transit would be preferentially routed off-disc, so far as the starship ranges allow. Someone who approaches under the cover of the disc could be assumed to be a hostile raider or a smuggler out to try an UFO landing.

 

[AotrsCommander]

I have been thinking hard about this (which is good because I'm at least engaging someone to start asking difficult questions). And I realized you are sort of edging around a fundamental question: "why doesn't everyone just pick two stars and FTL along the line between?" Or, perhaps pertinently, "why, when the Cybertanks launched Incursion 25 a few years back to directly attack Earth(-N), did they wait until they have their point-to-point Beacondrive and didn't just, like, point a massive fleet out of Metalyka towards Earth and let rip yonks ago?"

Which I have not previously ever properly answered, even to myself, so here goes. The explanation has always been a bit hazy and incomplete.

(In short, my usual go-to is, of course "it's complicated...!")

It is also dependant on exactly WHAT type of FTL you're using of course, but the majority in local space do use hyperdrive.

Quite a few species also discovered warp drive (no, not that one) first, but the only human ower to still use that in preference to hyperdrive is the SSA. Warp drive is a point-to-point teleport FTL (which a significant refractory period between) and it is fundementally waaay less safe and reliable than hyperdrive or begin with, so the discovery of hyperdrive made most people change over. (The SSA, been a conglomeration of corporations had the biggest state in warp drive and continuted to stubbornly refine it. As such, they now have very compact FTL drives, but their net FTL speed is very low (to some extent trading speed off for reliability and safety concerns). But until their complete secession, they were not strictly anything other than a big corporation with its own colonies.)

Hyperdrive is safer. But safer, not "safe." (Arguably the safest form of FTL transit is Aotrs Gate drive, because they (okay, their leader specicially) literally invented the properties of Gate space.) And contrary to convention, hyperspace and it's eccentircies are not a poorly-understood mystery, they are all actually very well documented. Hyperspace, then is just like using fire or electricity; perfectly safe as long as you're not stupid with it.

Basically, hyperspace opens a portal opened by emitters into what is basically a wormhole like tube of irregular rings of pulsing colours. Hyperdrives are not themselves a form of engine, they are just what accesses (and maintains) said wormhole-like-space - you need to use your drives to actually fly you into it.
If you turn your hyperdrive off, you are somewhat rudely dropped back into real space somewhat erratically.

So being in hyperspace still requires the emitters to be active (originally, the opening emitters and sustaining emitters would have been different, but before long, everyone figures out you can just tweaks them to do the same job). Which uses energy. And the longer you spend in hyperspace, the more energy it requires to hold you there - and, most pertinently, to keep hyperspace stable.

The way in which hyperspace intersects reality is not uniform. As I have noted, the interaction around gravity wells "lengthens" the distance of the worm-hole, but that is neither the whole story nor quite strictly accurate. There is an underlying.. structure might not be the right word, but it's first thing in the morning (okay first thing in the afternoon) on a Sunday... to hyperspace. I think it would be most akin to saying it's sort of like a contour map, rather than, like "tides" or something. But there are bits which have a lower energy cost to enter and sustain and those are the safest points. Which is why you have to program a hyperspace course before jumping, and why an emergancy jump where you just hit the hyperdrive without a course and hope is only a last-ditch effort to escape from being destroyed.

I have, I think mentioned that there are parts of a solar system (quite frequent) which are "safe jump points?" Those are where the fabric of hyperspace is most stable, easiest to get into. For your abolsute minimum effort and energy expendature (important for mercants, not so much for militaries), you want to be entering hyperspace at these points, but more complex than that, which point you want to use for a particular destination requires some optimisation. (That's what takes the time to program the course.)

While the "wormhole" looks straight, that's only perception as the interaction is actually not, but a very complicated twisted path. In the main, this meaders erratically around the direction of travel. Perhaps it might be illustrative to think about hyperspace being a stony beach, where your optimum path is to go around each stone. The path won't be straight, but it will be winding only in the local area.

So what happens if something goes wrong? What happens if, instead of walking down the metaphorical road, but try and climb the mountains (or through a stone, in out beach analogy)? Bad things. The most important bad thing is that you emerge from hyperspace in a random place. Most of the time, roughly in the area you were (like when making an emergancy jump), but it's on a bell-curve line and no-one is entirely sure where the maximum lies. Certainly ships have disappeared occasionally, so they could be anywhere. (It is believed strongly unlikely they would have gone outside the galaxy, but...) The other thing is off these "routes" your energy requirements change, and if you hit a big "spike" you can knobble the hyperdrive. (So if an emergancy jump goes wrong, you can end up at a random point in space with a busted hyperdrive.) If as you approach the limit of power you can put out to hold the wormhole, you emitters go unstable before they shut off, you massively increase the risk of an unstable scatter. Worse, there exists a possibility that unstable emitters will get "caught" (akin to getting muscular paralysis from an electric shock) and stay on, drawing off more power and not only potentialyl damaging you hyperdrive, but also your power core or even draining your reserves entirely. (Most races thus have safety shut offs which cut the power to the emitters before they go unstable for exactly this reason. You will get dumped uncerimonously in real space either way, but the scatter and the damage is typically less severe.)

The "structure" of hyperspace and the way it interacts with reality is affected by a large number of factions, of which gravity wells are one and in two different and opposing directions. On the one hand, the presence of a g-well lengthens the wormhole, meanng you have to fly longer to get the same real-space distance (ths thus g-wells decrease speed). On the other, the very passage of a gravity well across the universe it basically what creates the contour map, like a three-dimentional ripple n the structure of hyperspace (albiet an extremely complicated one). Thus, within the galaxy, the presense of stars basically makes the lows of the contour map. Intergalactic space, however, has either never had stars pass through it, or so infrequently or so long ago that hyperspace goes back to its default, ground state. (Even then it may not be strictly just "level", but the lows, as it were are much So going outside of the galaxy is basically not optimal, since while the speed is greater, the power and danger factors increase dramatically.

(It is believed that a similar effect acts on more or less every form of FTL transit in some way or another, but none of the rest (save maybe Gate space) are as well understood), but also in a lot of cases like the various teleport drives, there is simply a strict power limitation controlling how far you can teleport.)

So, basically, what determines how you get from point A to point B is a complex interaction of factors of:

a) the theorhetical length of the wormhole tunnel you have to fly through; increased by factors, including g-wells and well as obviously the spatial distance to cover.

b) your own (sublight) engines and thus drive speed (this does make a difference, though it is much less pronounced thatn the advancement of your hyperdrive technology)

c) the amount of time you can safely sustain in hyperspace before the draw exceeds your output and you have to basically drop out (resetting the power drain) and recharge the emitters before carrying on. (Or Bad Happens.)
Now, the aforemention Lazerblasters and the Shardan (at the top of the tech tree) basically don't have much of an issue with the power factors (because they are one terrifying heartbeat away from being an Out of Context Problem) and they have access to essentially infinite energy. Well, more correctly, unlimited energy. To all outside understanding, their "generators" don't actually turn one thing into energy, they actually generate energy. (Though from context this is suspected to be ultimately still drawing on some extra-dimensional source rather than them having the capability to ignore physics to create and destroy energy, if only because of the surprise exhibited when some of the most dangerous Lazerblasters have been documented to be able to do that.) For these species, then, it's a problem of throughput and their throughput it enough that they can fundementally largely ignore the contour map and even safely transit through the highs of hyperspace with negliable effect.So, apart from hyperdrive and warp drive, what other FTLs are there?

Aotrs Gate drive (which has a whole extended explanation I won't repeat here in that afore-linked thread), which is a unique technology.

The United Concorde of Divine Realms uses a form of magitech teleportation as well, supplemented by fixed-point artifical Node Stations, between which basically reduce the distance quotient of teleporting to local.

The elenthnars use Garrast-Viyroub Drives (GVD), which are sort of simialr to how hyperdrives work, but use a different sort of interdimensional space. GV space is more efficient in terms of speed and energy consumption within GV space itself, but requires a greater power outlay to initiate than a similar-sized hyperdrive and the stress imposed on the vessels is much greater. (Unlike hyperspace, which can be safely accessed by any vessel entering one of the very rare natural hyperspace gates, an unprotected vessel entering GV space is at considerable risk of damage.) Unlike hyperdrives, GV drives mandate physical consideration of the vessel structure, whereas hyperdrive can just be slapped on pretty much any geometry, since it doens't matter.

In addition, they have Dro'Sanla drives, which are fundementally an attempt to back-engineer UCDR magitech with mostly conventional means. GVD is the standard, with Dro'Sanla drives being mostly confined to tugs to pigtgy-back onto UCDR Node Stations. (Except for the Phystyulons, who exlcuively use Dro-Sanla.)

The Stone Portals use super-space, but this is very poorly understood, but seems to function a bit like hyperdrive or GV drive.

The Rift Collective use a likewise not well-defined form of advanced teleport drive.

The lyrokanas (including their most visible nation, the Jalyrkieons) use a type of gravitonic propulsion that works off the underlying fabric of subspace. In concert with an effective-mass-reduction field, the same system allows them FTL transit through normal space. The technology requires a fairly small amount of mass and volume to operate, though the disadvantage is slower transits speeds (at both sublight and FTL speeds) and much higher power requirements. Like most gravity or force-field effect propulsion systems, the drives function without significant visible emissions, though the drive unit themselves are very distinctive.

Several other minor powers use a similar "straight line" real-space distortion drive as well.
I think that about covers the most important stuff, I think?

 

[snorkack]

Are there any ways of deliberate FTL message transmission, faster than FTL transit of objects?
What are range limitations of FTL messages?

 

[AotrsCommander]

FTL communications are generally all capable of transmitting at FTL speeds, at least sufficiently to generally make time lag between places negligable within the spheres of influence. The galactic net exists as a dispersed congloerate, and most powers have access to it (though what you may be able to get rather depends on how you are which which bit of the 'net you're trying to access, at least on the civilian level).

Communitcations ae pretty ubiquitous, with even noddy little back-up helmet communicators having AU ranges and actually hand-held comminucators having ranges of light years (both without any starship or satelite support to boost the signal ranges).

In general, within the range of a given communicator system, there is no appreciable time-lag. Range is based on power and technology (and this latter does vary considerably), but if you are within range, you're generally fine. (This of course discounts stuff like jamming, EC or spatial phenomina that will interfere.)

(At the very top end of the power tier list again, communications rely on interdimensional methods and if there is a maximum range (even between planes of existence), it has not been measured yet.)
In general (and somewhat related), sensors are also FTL-capable. (Being in FTL transit does not make you immune to detection in general, though there is some aspect of the interaction between how fast/good your FTL is compared to sensors if you were to rush through an active detection field). Otherwise, basically the only way to avoid detection is by active installation stealth or cloak technologies (and those are exactly as effective as your relative advancement compared to the folk looking for you).

(Also, the relative ease in which FTL jumps can be made within systems generally means that very long-range engagements are not unheard of, since beyond about 10 light seconds, you can safely make a normal FTL jump.)

That said, there's a big difference between the range of the passive sensors that just pick stuff up at range and compare to known data, and the actual range at which you can do a proper scan, which tends to be a bit over half a million klicks for average sensor tech on a non-specialised-sensor warship. So if you want to learn something about, say a new enemy vessel to do a proper scan, you need to get basically well within combat range. Thus, you can get maybe a rough idea of the magnitude of a power spike of an unknown ship from passive sensors even at long distances, but in order to scan for lifesigns and such, you'd need to get within active sensor range.

 

[snorkack]

Compare Asimov´s Foundation series. FTL communications existed, but after the fall of Galactic Empire in the Periphery in "Foundation" shortly after 50 FE, Foundation and Empire were out of contact for 150 years, with a brief and limited exception in "Big and Small", around 154 FE. In "Bridle and Saddle", 80 FE, Salvor Hardin, the ruler of the smartest country and a scientifically curious person, reflect that he has no clue if Empire still existed or if it had collapsed in the centre shortly after collapsing in Periphery. It eventually did collapse in the centre, but only two centuries later. In "Big and Small" and "The Wedge", we learn that the remaining states in Periphery still had FTL travel and communication - it was just mainly short distance, maybe a few tens of parsecs, not thousands. In "Dead Hand", we see that the hyperwave transmissions have a limited range: Lathan Devers was in hyperwave contact with Foundation, but it was difficult because of extreme range. Presumably Empire could keep instant communications thanks to series of repeating transmitters. Once the political control of Periphery collapsed, the repeating stations were no longer cooperating and no longer forwarded even general news.

 

[AotrsCommander]

It's something of a grey area, admittedly. I have deliverately no gone into specific details, because comms systems are likely sufficiently complex as to have multiple ways of working and technology that changes more frequently. There's a lot of different communications technologies, and the varying levels of technology means that if you have superior gear, you can generally tap into other people's communications systems whether they want you to or not. (Which is why, for example, the Aotrs have access to the galactic net despite the fact that the Royal Elven Kingdoms and the majority of human powers would rather they didn't, but they basically don't have a choice and the Shardan and the Lazerblasters can theorhetically get remtely into anyone's computers systems; hell even the ones not connected to a network!) If you're at parity with the target, you obviously have to work at it to make it interface and they might stand some chance of stopping you.

(The range and transmission speed also will vary by technological advancement, too.)

The galactic net is otherwise something of a buy-in, though, as to be part of it, you do have to have the appropriate relays that are, like, at least compatible. (Neither the Orc Fearcrushy nor the Cybertanks use it, for example.) But a space-faring power that is remotely interested in any kind of diplomatic relations with anyone has to has it (in the same way on Earth now, you basically can't function as a business without the internet). It's notable that the most prevalent inter-power cultural trade often occurs digitally, via media (though against peer-level technologies, there is some control of what your own power will let you access. Not everywhere will let you just go watch, essetially elven telly, basically; because humans and humans and the fact the elves don't have the same sex/violence double-standard means elven entertainment has gotten an entirely undeserved reputation for being pornographic.)

But the relays aren't necessarily limited by bandwidth like an internet cable; if the relay exists and is compatable with your communications at all, there's a strong chance you can just bounce your emissions through it by dint of it just, like existing.

(Via a related example, the UCDR are not very happy with the elenthars being able piggy-backing onto the their Node stations, but there is literally nothing they can do about it, since it simple doesn't work like that. The node stations are basically akin to opening a some-light-years-wide window to another portion of the galaxy, and they thus can't stop someone chucking thing through the window other than maybe in the region some lass is playing goalkeeper with a goal a mile wide.)In the instances were there ARE no relays and ongoing traffic, though, it can tend to disappear into the unknown. The collapses of the Strayvian Empire and the removal of their infrastructure did, in fact lead to basically such a black hole of information corewards of human space. (Not that modern human communications systems could interface with Strayvian communications of the time anyway.) With the re-emergance of the Strayvians in the Strayvain Dominion being an really unpleasant surprise. (In fact, given the Stravyian tendency to act like moustache-twirling supervillains, very much akin to the wham episode where that villain you thought was dead is back...!)

In addition, without being close enough to pick up such point-to-point transmissions with sensors (assuming your sensors are advanced enough to pick up their communications), you obviously can't point to a section of the galaxy you know nothing about and listen in.

(Being in hyperspace or Gate space, incidently, does not block communications, or at least not modern ones. Most teleport FTLs have jump times so quick it's not an issue.)

The range of full-sized (military) communications systems are enormous, at least point-to-point, even without relays.

Notably, the Aotrs were able to contact a fleet in transit across the galaxy (a fairly long trip) to the Daming Echo base to order an emergancy jump without any appriceable delay. But Daming Echo base was founded by the Aotrs Myst Expeditionary Team (which basically is analogous to a Star Gate, using the Myst Gate to explore point-to-point), and in order to maintain contact with their ground teams, the Myst Gate has to be open (held to at least a pin-prick). Though, granted, by definition, the ground teams obviously can't carry starship-grade communicators with them.

But we can infer from the incident that the Aotrs communications systems at least (which are above the galactic standard) have no transmission time, and have a range of thousands of light-years, at least between major communications centres. The order came directly from the Aotrs military capital, and it logically follows that Echo Fleet, which was explictly heading out to become Damning Echo's defence fleet, would have specialist long-range communication gear, and likely would have been carrying such gear to Daming Echo, which likely simply could not have fitted starship/installation scale equipment through the relatively small Myst Gate.

That's the most obvious example I can think of which illustrates how it works.

(It is quite likely that such military-grade communications might be able to use something Mass Effect's quantum entanglement devices, which if I recall correctly had fundementally unlimited range, but only between two points, if perhaps only on some specialist ships or locations; but as I say, it's a bit hazy.)

However, it's almost certainly not the case that the average citizen of, say, the British Space Empire could talk to someone half-way across the galaxy using civilian channels; that WOULD be dependant on the relays and communications systems.It is perhaps a bit fundementally like mobile phones are far as communications go; in the local region at least, within a power, there's likely so many relays that in order to affect a black-out, you'd have to work really hard. You could probably manage, with a suitable specialist piece of gear to disrupt a single system's communications but that would require a disproportionate amount of effort akin to fielding a doomsday weapon. So most of the time, it's not worth the bother trying.

In general then, the denizens of the galaxy have had to learn to deal with the problem modern horror movies face - communications are more or less a given and stuff that relies on people being out of communication is basically not a tactic you can generally expect or exploit - at least as long as the communictions systems remain undamaged of couse. (A single ship lost in space with knackered communications is still stuffed - it WOULD then be stuck using slower-than-light communications.)
So yeah. In (any given power's) Known Space (and potentially with ships with the right gear operating really far from their Known Space), communications is going to be mostly instantaneous. But if you aren't in range of appropriate communications systems, you don't have FTL communications at all. There's no increase in lag (save perhaps a by-product of Wibbly Spacial Anomoloies and the like!) as distance increases, it's either on or off. Thus basically FTL communications are basically binary. You either have instant FTL communications, or you don't them at all, and have to rely on SLT systems. (Which given the scale is fundementally the same as Not Having Them other than in-system.)
(Sorry, that was perhaps a bit rambly again, but I will insist on writign these up first thing before breakfast...)

(Now wait until I find something that contradicts all that in the existent canon, but the Aotrs example, at least stands...!)

 

[snorkack]

One obvious thing to do is to code the FTL messages, and not share the code with the listeners.
But even an encoded FTL message is an artificial phenomenon, so the listener can deduce sender´s existence and location...

 

[AotrsCommander]

That would be practise for a lot of powers, yes, but again, encryption only works so far as other (especially more advanced) races being can't crack the code.

(Then you potetinally have translation issues, but universal translators are not unknown, though it must be noted that the "universal" part is, as a wise scholar once said "a lie of sorts" and stuff that is very far off from humanoid (and elenthnaroid) or really complex/strange does not necessarily translate. (Notably: Stone Portal and Grey Watcher In The Mire (Rift Collective) languages.)

And yeah, you'd still have to be in a position to detect the FTL communication emissions, which means you still need to be with in sensor range to pick up comm chatter.

For the odd very long communication like the one to the Aotrs, space being so fracking big, the chances of someone picking up that signal is pretty small, and in isloation, not likely very helpful even if you decrypt (and then translate) the signal. This would be something that happens occasionally - the odd alien transmission will show randomly - but without a fairly sustained presence, it doesn't often tell you much other than Something Is Out There. But there will of course be whole fleets of xenoscientists whose calling it looking at this sort of stuff, but progess is not usually helpful on a militarily important level.

 

[snorkack]

Though, granted, by definition, the ground teams obviously can't carry starship-grade communicators with them.

When they are merely "teams". Do constructed bases, which in their assembled state are not subject to starship requirements of portability, have higher grade communicators than the starships which delivered components of communicators?

Sending scout ships into a region where FTL capable aliens are known to be around is risky unless the aliens have been assured to welcome the action. The aliens might attack the ship, and/or perceive the action as provocation and send their own FTL ships to attack.

One logical way to find out at least some basics about your FTL capable neigbours is staying in your own backyard and peeping. Listening to FTL waves: deliberate transmissions and the noises of FTL travel. The transmissions may be undecipherable because of unknown code, possibly deliberately obscured - but you can take bearings, use these to identify transmitter locations and find out FTL silent stars (no interest for locals), FTL quiet and FTL loud systems.

 

[AotrsCommander]

When they are merely "teams". Do constructed bases, which in their assembled state are not subject to starship requirements of portability, have higher grade communicators than the starships which delivered components of communicators?

Sending scout ships into a region where FTL capable aliens are known to be around is risky unless the aliens have been assured to welcome the action. The aliens might attack the ship, and/or perceive the action as provocation and send their own FTL ships to attack.

One logical way to find out at least some basics about your FTL capable neigbours is staying in your own backyard and peeping. Listening to FTL waves: deliberate transmissions and the noises of FTL travel. The transmissions may be undecipherable because of unknown code, possibly deliberately obscured - but you can take bearings, use these to identify transmitter locations and find out FTL silent stars (no interest for locals), FTL quiet and FTL loud systems.

FTL comms are much harder to detect than FTL signatures from ships, because you have to be more or less on top of them to find them, whereas FTL signatures are more readily visible. So, in general, you will find communications by looking at where ships are, not find ships by where communications are.

Basically, there are fundementally three types of sensors: navigational, passive and active. Navigational sensors are the longest (intersystem) range, but they will only pick up stuff like planetary bodies high energy emissions at that range; like FTL transit but only IF the sensors are sufficiently advanced compared to the FTL drives. (Even if they're using the same type of you, if you're using human technology, you quite likely won't be able to pick up Stravyian hyperdrives because they'd potentially be moving faster than the granularity of your sensors.) Mostly, the navigvational sensors are otherwise mostly for detecting unknown planetary bodies via SLT data. (Now, if you are dealing with a known sensor profile when you pick something up, even navigational sensors can usually flag more data on it, but that requries you to have encoutered something to do a full scan on it beforehand.)

Passive sensors are something closer to in-system range (i.e. significantly less than a light-year), and they will generally pick up ships, energy emissions, presense of lifeforms (maybe flagged up if they are a known species); everything not actually being actively hidden... But aside from broad-spectrum emissions like distress beacons (which are of course DESIGNED to be detected), you're only going to pick up communications chatter if again, you have something close to parity or between your sensors and their comms systems.

(Active is basically like Doing A Star Trek, but to get that sort of detail, you have to basically be within weapons ranges (maybe a few increments of weapons range if you have a big sensor array).)

Again, if you are dealing with something familiar, your passive can provide you with quite detailed information by comparison, but that's not much use if you don't have a signature to detect.

Obviously, powers will have larger sensor stations and watch-posts with sensor arrays watching their borders, but that's about as far as it goes. With a lot of time and years and specialist gear, you might be able to work out that a particular bit of space has something in it or not and there will be a few SETI-like organisations in many powers devoted to this sort of thing- and with probably about the same level of funding an emphasis as modern SETI. Because, functionally, at this point in history, the range to unknown space now very significantly exceeds the range at which you can do that with any degree of reliability, since you don't have the same functionally-infinite-range-but-as-a-function-of-time like STL detection systems.

You can't (anymore) sit and Do A SETI and look for the metaphorical equivialent of radiowaves passively, then; plus there is the problem that if you can't detect any communications that just means you can't detect any communications and absense of evidence is not evidence of absense. (But the lack of any FTL signatures is more likely to tell you that.)

You're more likely to learn of the presense of a power by word-of-mouth from explorers, past history or their neighbours, at least at the late stage in the game, as it were, as the galaxy is now, with the average power having at least a few of centuries of being FTL-capable.

(If you're ever played something like the game Stellaris, the galaxy is pretty much largely at the point past the early-game and has reached the point everyone is bumping into each other's borders, metaphorically speaking.)So you will detect an incoming Cybertank fleet and have some rough idea of the size in sufficient time to get a defence fleet there, but you likely won't know the exactly composition until you're looking at it; and pretty much only at THAT point then will you be able to detect comms chatter.

With specialist gear (like sensors-specifically-designed-to-detect-[insert-power-here's]-comms and their specialist operators), pointing in the right direction, you might be able to squeeze more range out of it than intersystem.

Notably, though the limitations are illustrated by the Cybertanks; the Cybertanks are fairly close, have been around a long time, are at war with literally everything that is not a Cybertank and they basically only have a single system to "watch" and you will STILL only get a warning of a Cybertank incursion raid by detecting the ships entering your space.

But in truth, you will usually get more data by just sending recon ships (or very-long-endurance probes) carefully in for listening watch. (Powered down and near a stellar body, you have a fairly good chance of not being detected as a ship by passive sensors - the moment someone pings actively though, you'll show up like a sore thumb.)

(The Aotrs explictly use their stealth-capable Traitor recon destroyers deployed - sometimes not even in a system, but the void of intersystem space - to park up and passively and do exactly this. Doing what real-world recon units actually do; functionally counting the number of trucks; as opposed to trying to do radio- (or more pertinently, mobile)- intercepts.)At the end of the day, then, there is ultimately no way to avoid having to do recon by going into somewhere and having a look around. It's risky and that is how Bad First Contact Happens. On the other hand, it's risky just being in existence, since if powers like aforementioned the Cybertanks find out you exist by their direct "send ships at you", they'll come for you anyway.

 

[AotrsCommander]

For the sake of a coda, that round of discussion with snorkack in the end prompted some entries on FTL and FTL comms and sensors to the tune of 22.9k words.

I'm not sure it will actually really interest anyone in the end, and given that my physics education is primarily the maths from by engineering degree twenty years ago, actual physicists (et al) might probably find it a bit too hand-wavy in places; but never let it be said that I do not, at least, make my most spirited attempt at it, and at least, a vaguley popular-science-y explanation with some level of plausibility. (If nothing else, one hopes it it shows I did Think About It and I'm metaphorically showing my working...)

 

[snorkack]

FTL comms are much harder to detect than FTL signatures from ships, because you have to be more or less on top of them to find them, whereas FTL signatures are more readily visible. So, in general, you will find communications by looking at where ships are, not find ships by where communications are.

A problem with that is that if you do not have a communicator more powerful than the side effects of ship travel itself, you are likely to use ship travel itself for signalling. Like, if you cannot just call the Martians, you can undertake trips between Moon and Earth purely for signalling as the code agreed. Or agree a code into routing and timing of the Earth-Moon trips.

 

[AotrsCommander]

A problem with that is that if you do not have a communicator more powerful than the side effects of ship travel itself, you are likely to use ship travel itself for signalling. Like, if you cannot just call the Martians, you can undertake trips between Moon and Earth purely for signalling as the code agreed. Or agree a code into routing and timing of the Earth-Moon trips.

I am not sure I'm quite following your point (since communications are point-to-point and instantaneous within the extent of the range, whereas FTL transit takes time). I'm not sure what power has to do with it.

Basically, FTL communications are not wide broadcasts like STL communicators, so you can't look for communications transmissions from aliens because, fundementally, there AREN'T any. I.e. if you are not standing between the two points in commuications (or very close as galactic distances go, to to the "line" between them) you basically can't see them.

I did a much more expanded and coherent explanation when I put this up. but I'll just try and paste the relevant bits here (I omitted a second on blocking communications, since it didn't seem pertinent to the point in question).

There isn't really a TLDR, since I am physically incapable of making one, but the very gist is, if you want to find new aliens, you basically have to send ships looking for them, and you'll spot their ships before their communications, unless they have not themselved developed FTL comms and are stuck with STL communications. (Which, given the way the universe was manipulated and created, is a fairly small probability.)

Assuming they haven't extreme exotic communications systems (one the one hand, there are only so many ways to skin the FTL cat; on the other, the Extra Galactic Aliens for example, appear to solely use telepathy as their communications system), odds are it would not be terribly difficult to open a channel to one (or more, if you want to do a "full spectrum/wide" broadcast) of their communications "dimples" in the fabric of reality that are within your "electric arc between points" range.

Then you "just" have the language problem.

("Hello we're friendly" broadcasts across the galaxy are thus not really practical, since with FTL comms you can only reach as far as the furthest node in the grid, STL comms take forever. Plus, it's not a terribly good idea to be broadcasting you exist to everyone, since there are quite a lot of powers to whom "hi, we exist" is a direct challenge for either conquest (Strayvians) or obliteration (Cybertanks).)

Communications

The very first dedicated FTL communications systems of most powers were simply automated FTL buoys (most often warp-drive or hyperdrive for many powers). The buoys would be dispatched, either on command or a regular basis, between systems. This was both expensive and quite readily able to be interrupted.For those powers that had developed hyperdrive, experimentation often proceeded with attempts to send pulses in hyperspace (or at least along the hyper-stratum with later understanding). These experiments sometimes succeeded, and sometimes did not (the Royal Elven Kingdoms managed a workable system, Earth-N did not), but they were little if any faster than a starship courier and required a disproportionate amount of energy.

Ultimately, it was the quantum entanglement which eventually provided the impetus for true, long-range FTL communications. The science of quantum entanglement itself, let alone the more advanced sciences that spun off it, is a heavy topic to broach, but the simple explanation is that if you do something to one particle of an quantum entangled pair, the other shows the same effect, even if they are separated widely by distance. With a series of these, you can use this to transmit data.Quantum entanglement itself became something of a dead-end technology. As it relies on pairs of particles, on at each end of the communication, it limits the system to between the two fixed points. In order to have a communications network, the number of pairs for each separate node quickly snowballs. For a typically a century or so, such systems lingered for critical communications links between the governors of planets, but eventually, they were superseded.But the idea persisted. Between the knowledge of other-dimensional spaces like hyperspace and subspace and teleportation (powers with access to magic had a greater head start here), could there be a way to use those spaces to, essentially instantly transmit data from one point to another?The answer was yes. It was answered in a myriad of ways, by various powers. Indeed, modern communications systems are not a single device, but a plethora of various transmitter and receiver devices in them, acting in concert. However, all these devices have more or less the same convergent properties (there are only so many ways of doing things, after all), which means it is very rare for even unknown species not to be able to interact on at some level.The single largest feature most FTL communications systems have in common is that they are all, fundamentally, still point-to-point, going directly between the nodes of the communication units. The speed of this communication is effectively instantaneous. However, the terminology still refers to "transmitting" and "receiving," since the time in which the data travels is not actually instantaneous, and there is measurable travel time. The differences are so small, however, that to get true lag, distances would be in tens of thousands of light years – far beyond the range of the current communications systems.Furthermore, unlike theoretical perfect quantum entanglement systems, however, the range at which a communication system can do so is limited. While a larger array can connect to a node further away, there is a limiting factor of technology how large an array can become. (Especially so on a starship.) To once again re-visit and inaccurate-but-illustrative example, like an arc of electricity jumping between two points – too much distance and the arc cannot leap across the inherent resistance of the air; in this case, the communications signal is the arc, and the "air" the underlying fabric of the universe (and/or the other-space the signal is sent along).A full-spectrum broadcast, like an unshielded civilian transmission or a distress beacon may be thought of as arcing simultaneously to all nodes within range. (These signals are so-called because it will transmit across all of the pertinent devices in all directions.) A transmission that is more directed (such as between warships) would be between specifically selected nodes.The range can be increased by transmitting the signal through another node, however, making the true transmission range only limited by the extent of the node network. The un-augmented range of a modern communication is still significant. Even ancillary systems like helmet or scanner communications can reach distance of AU by themselves, and hand-held communicators can reach a few light-years, even without a starship or satellite from which to "bounce" the signal further. The difference in range due to size is also disproportionately greater, with larger systems having considerably better ranges. Dedicated long-range communications gear has even greater ranges, but these are usually only found on fixed installations or stations or on specialised fleet command and communications ships. I.e. specialist support vessels above and beyond normal, smaller communications vessels.

For example, in the Aotrs fleet, the Traitor Recon Destroyer serves as the communications vessel for task forces and detected fleet elements. But for an entire fleet (e.g. the Aotrs 1st or 2nd Fleet, which have hundreds of vessels including ancillary and support ships) there may be usually only one or two long-range communications vessels in the entire fleet. These specialist support vessels are not typically combat vessels at all, like the repair and refuelling vessels they accompany. (In the specific case of the Aotrs, such vessels are typically refits of large capital ships, often of prior generations, or aboard the few supercruisers, instead of a dedicated ship design.)This is further complicated by the fact that an active communication system, actively transmitting or not, acts as a dimple of lower "resistance" inherently – as it must to be able to receive any signals at all. Thus, if you are reasonably familiar with, and have at least technological parity with a power's communication system, you can "bounce" your own communications through these points of low resistance and further extend your range without actually interacting with their node directly at all. This somewhat reduces the range you can jump between nodes, however, proportionally to how "close" you come to actually connecting to their node (and thus them getting your transmission directly).This capability is limited to military-grade systems (legal or otherwise), though some very high technological civilian technology bases can do it if they are superior.

---

As an illustrative example of communications limitations in action, we can look back the incident transcribed in the postscript of the Guide to the Aotrs. To recap, Damning Echo Base is a facility located by the Aotrs Myst Exploratory Teams through the Myst Gate, which lies significantly across the galaxy. Damning Echo Base is sufficiently far from Aotrs space that direct communications to it are only possible once relayed through Myst Base with the Myst Gate open. (This is the case with the majority of the AMET expeditions.)

At the time of the incident, the new Echo defence fleet had not even arrived at the facility; it was at least three weeks away from Damning Echo and already well out of Aotrs space. However, Lord Death Despoil was able to contact Echo fleet and immediately issue orders.This was possible because Lord Death Despoil was on Fearmore, which as the capital world has significant communications facilities of its own. However, Admiral Fellbane's fleet also would have specialised long-range communications gear on the fleet command vessels – the sort of vessels which do not typically sit in the main battle line, but remain with transport units in the rear deployment of a combat zone. Echo fleet was also transporting more such equipment to set up at the base, specifically to be able to communicate with the far-distant Aotrs space. This equipment was of sufficient size that it could not be transported through the Myst Gate, which was why Damning Echo was still reliant on the Myst Gate for communications.

---

So, on the one hand, modern communications have only a limited (but large) range to which they can transmit or receive from another unit; on the other, if the unit is in range of the transmitter, there is no perceivable lag. The effects of enemy ECM, spatial anomalies and other phenomena can have an effect on signal clarity, communications range and even signal lag, but these are rare exceptions to the rule.

It is rare, then, for a star system to entirely lose communications altogether. The nightmarish scenarios of colonies lost for centuries when they dropped off the grid has thus failed to materialise, because the modern grids are so dispersed as to be indestructible on a practical level (unless the colony itself is completely levelled). However, this can occasionally happen in specific circumstances.The fall of the Strayvian Empire caused such a black-put to occur in their former territories. This was in part, however, due to the Strayvian's own control-freak tendencies, where they had made a spirited effort for control the flow of information through their own communications arrays. They could achieve this due to their technological superiority at the time. These arrays were all destroyed during the various rebellions, as they were all, ultimately, military facilities used by the occupation. The surviving powers did not build replacements, or if they did, with but a fraction of the strength. And so the region remained a black box until the modern era, which meant that humanity had no prior warning of the Strayvian's sudden re-appearance a hundred and fifty years later.It is thus possible to see how a species that did not discover FTL communications technology could fall prey to such incidents. Given the variability of the ease at which one can break through into other-space, it is possible a power in a fairly difficult region might not find access to the means required. (This is one suggestion as to why the elenthnars did not discover hyperdrive first.) So there may indeed be unknown empires out in the galaxy which still have to rely on STL communications methods.Intercepting Communications

Actually intercepting communications (as to be able to read their contents) is quite difficult with FTL communications gear. As such transmissions are, by nature point-to-point, they leave no trace when not active. Unlike slower-than-light transmissions which can spend centuries crossing the void of space, in order to be able to intercept an FTL communications system, the interceptor needs to be within sensor range of the communicators to be even able to see them. This usually means navigational sensors [a few to a few tens of lightyears, dependant on the size and technology of the sensors], since while possible with active sensors, the chances of catching FTL communications in the much smaller bubble are drastically lower.The sensors also need to be sufficiently advanced to be able to detect the transmissions. Finally, even if the transmission can be detected and read, there are the problems of breaking encryption and translation.

While "universal" translators exist (and does translation magic), these generally are only helpful for extrapolating from all known languages and/or are geared specifically towards the humanoid (and elenthnaroid) brain. Extremely esoteric or alien languages are beyond their capabilities. Notable examples of languages are extremely difficult or near-impossible to translate even by linguistic specialists (with dedicated computers and/or magic) are the Harbinger, the Stone Portal and Grey Watcher In The Mire (i.e. Rift Collective) languages, as is the encoding of a Cybertank's brain.In the earliest days of space-travel, sensor arrays focussed to looking outside of a system had to rely on passive systems like space telescopes, or like Earth's SETI program, hoping to catch stray alien STL transmissions. As technology advanced, the early FTL phase saw these sorts of programs have their golden age, with large arrays of navigational sensors, looking towards other parts of space in the hopes of likewise catching information.However, in generally, FTL transit is much more readily visible than FTL communications, and it is thus always a far better indicator of the presence of an unknown power. (That said, absence of evidence is not evidence of absence – not detecting any FTL signatures in a region just might mean that it is too advanced for your sensors.)In the modern era, then, such sensor arrays are back to the prominence of their origins. As the civilisations of the galaxy have expanded, so the reach of fixed installations has relatively shrunk, since they cannot now look past their neighbours. The programs still exist in the larger powers, but now the distances they can usefully reach into space that is not known to be occupied is increasingly small. This is not to say these methods are useless – the existence of some powers known only by name (such as the Flangz or the Valkan Worlds Alliance) comes from this sort of information source.But in the main, exploration is now as always, best done by sending ships into systems, despite the greater risks this presents. The single greatest risk, of course, being of appearing in the wrong space and starting a first-contact war. However, as might be noted, with the known galactic powers like the Cybertanks, Strayvians or Blastarons, more or less the worst has already happened. Any other such power would present merely a threat in their magnitude of their strength and their capabilities while those remained unknown. It is, after all, difficult to conceive of a species that could be more xenocidal than the Cybertanks we are already so familiar with.