#g2hge

You remember Turix, right ? From lore that's not at all insignificant and obscure ?

March 18, 2185 : “Astronomers are excited tonight as the probe TR-15 Letus comes the closest any probe has ever come to a neutron star. The star in question is in a globular cluster approximately 18,000 light-years from Earth. Though it contains slightly more than two times the mass of Earth's sun, its radius is a tiny 15.8 kilometers, spinning at approximately 24% of the speed of light. The probe was sent to the star via the Kappa Iota Relay, a charted but rarely-used relay predating the Rachni War. The relay was abandoned due to the highly lethal radiation found on the other side, but the small doses that pass through the relay are manageable for a shielded probe. Control of the radiation emission and reception of Letus's signal is made possible by the infamous Dark Switches, a set of previously unknown control functions the Protheans installed on mass effect relays.”

May 26, 2185 : “The astronomical team that launched the TR-15 Letus probe is being blasted by the scientific community for falsifying results about the neutron star Turix. "The data they were posting was too good to be true", said Dr. Aurana T'Meles, who reviewed their work. "When they claimed to have sent the probe through the relay leading to Turix, we all wondered how and why the Protheans could have built a corresponding relay so close to such an energetic star. Then came questions about isolating the probe's signals from the radiation, claims of unprecedented dark energy control -- I would almost go so far as to use the word 'hoax'". Letus team lead Dr. Akil Carinii apologized for what he called "sloppy record-keeping" but insisted his findings were authentic. "The galactic community has but scratched the surface of all the functions of mass relays", he said, "and my team will continue to try to solve their mysteries".”

Key takeaways :

Turix is a very energetic neutron star ;

It is in a globular cluster ;

It is 18,000 light-years from Earth ;

There is a relay close to Turix ;

Its twin is the Kappa Iota relay, which has been accessible since before the Rachni Wars (i.e. since any date between 580 BCE and 1 CE) but has been rarely used because of all the radiation on the other side, seemingly filtering through when the relay is active.

What if we tried to place it on a map ?

Our solar system is estimated to be between 12 and 22 parsecs from the galactic plane, i.e. between 39 and 72 light-years ; on the map we'll be using, the unit is the thousand of light-years, so we can assume, for our purposes, that Sol is flush on the galactic plane.

Sol is also about 26,000 light-years from the Galactic Center ; the Milky Way as a whole is approximately 100,000 light-years across and about 1000 light-years thick at the spiral arms (more at the bar in the center). Most of the stars of the Milky Way are situated in or around the galactic plane, but not all of them.

If Turix is about 18,000 light-years from Earth, we have to calculate where it might fall both on the galactic plane but also above and below.

If Turix is on the galactic plane itself, at its closest it would be merely 8000 light-years from the Galactic Center (in conjunction with it relative to Earth) while at its furthest it would be at 44,000 light-years from the Galactic Center (in opposition to it relative to Earth).

But what if it's above or below the plane ? Well, you know who to call… our good friend Pythagoras.

(That's right, who said geometry had no real-world uses ?)

We can assume that wherever Turix is relative to the galactic plane, it is one of the vertices (T) of a right triangle with another vertex being where the Sol system (S) is ; the third and right angle of that triangle being the intersection of the line passing through both T and the galactic plane that is also the shortest distance between both, i.e. a line perpendicular to the galactic plane. This vertex we'll call G.

We'll call that side of the triangle between T and G a, the side of the triangle between G and S b, and the side of the triangle between S and T c, the hypotenuse. We know that c = 18,000 light-years, and that a will be anywhere between 0 and 500 light-years (half the thickness of the galaxy) ; but if we want to place Turix on a map showing the flattened galaxy, as in the Galaxy Map, we need the length of b. As we want to calculate a possible range, we'll assume a = 500 light-years, which will be the maximal distance of Turix from the galactic plane.

Given that our triangle is a right triangle, we can calculate the length of any side as long as we have the other two, using the Pythagorean theorem : a^2 + b^2 = c^2 ; therefore, b^2 = c^2 - a^2, and b will be equal to the square root of the difference of c^2 and a^2.

c^2 = 18,000 x 18,000 = 324,000,000

a^2 = 500 x 500 = 250,000

b^2 = c^2 - a^2 = 324,000,000 - 250,000 = 323,750,000

b = √323,750,000 = 17,993.05 (and then some)

In practice, what does this mean for us ?

It means that, on the Galaxy Map, Turix would be anywhere between 17,993.05 and 18,000 light-years from Earth. As these are effectively indistinguishable on a map of that scale, that means Turix could be any point on a circle on the Galaxy Map whose center is the Sol system and whose radius is 18,000 light-years.

And maybe we can refine it further with history ! Since Turix was accessible prior to the Rachni Wars, then it can only have been accessible from one of the clusters which had been opened before !

LET'S BREAK OUT THE MAP !!!!!!!!!!

A few notes :

the Sol system is at the center of the red circle where Turix can be. I stress again that Turix can only be on the circle itself, not within it.

the three clusters within the circle who cannot not have been accessible on the eve of the Rachni Wars are the Annos Basin (salarian home cluster), the Aethon Cluster (volus home cluster) and the Horsehead Nebula (the only way for the salarians to access the rachni home cluster). The connections between these clusters and other clusters outside of that range are shown with full red lines ; the Aethon Cluster is not connected to anything because its only canon connection is to the Apien Crest, which wouldn't have been accessible before the Rachni Wars ; in other words, we do not know how the Aethon Cluster connects to the Citadel, and what other clusters (or neutron stars) may branch off it.

The clusters which may or may not have been accessible prior to the Rachni Wars are also shown, but with a dotted red line connecting them to surefire clusters. In practice, we only see clusters branching off the Horse Head Nebula, because while the Annos Basin and the Aethon Cluster must have additional connections, we just don't know them.

The territory with green borders is the presumed territory of the Salarian Union (+ hanar space, included and not set apart because we don't know when first contact was made with the hanar).

Within the red circle, there are two zones with parallel black lines the closer you get to the Galactic Center : the outermost black arc is the Five Kiloparsec Ring, an area of intense star formation around the galactic core too dangerous to travel. The innermost black arc is the 4-kpc limit, which is usually considered the radius of the deadly galactic core itself, and the inner limit of the so-called Life Zone in the galaxy (i.e. the zone where life could develop at all) ; beyond that, closer to the core, life is impossible. Note that the map suggests that salarian territory partly extends into these zones.

The dotted parts of the red circle are the furthest from the Citadel and the other accessible clusters prior to the Rachni Wars, meaning Turix is far less likely to be there.

At this point, the only thing we can be certain of is that Turix cannot be outside the red circle ; and moreover, that it cannot be in the central region of the map (the Galactic Core) as it is inaccessible. The closest to the Galactic Core it can be, historically speaking, is within the green region that's likely to be Salarian Union space.

Ah, fuck, I forgot to include the Serpent Nebula and the Apien Crest, which were both active (if unconnected) prior to the Rachni Wars, and which might both plausibly lead to Turix. Be right back.

Note that I am not connecting the Apien Crest to either the Serpent Nebula or the Aethon Cluster, since (for some reason) the turians were off doing their own thing until c.700 CE, i.e. four hundred years after the end of the Rachni Wars (and, uh, seven hundred years after their start).

This means, of course, that the turians had their own parallel mini relay network before c.700 CE.

Could Turix have been part of it ?

I'm not gonna lie, "Turix" sounds really turixturian, so I think the odds are pretty significant. Let's consider the circumstantial evidence :

"Turix" sounds turian ;

"Letus", the name of the probe going through the relay, sounds turian, i.e. Latinish ;

"Akil Carinii", the name of the lead researcher in charge of the probe, is 100% a turian-sounding name.

So it really sounds like a turian affair, suggesting turians first accessed and then ran away from Turix. But again, it could be circumstantial : maybe the star's name was a string of numbers, but Akil Carinii decided to name it Turix after his boyfriend or girlfriend or kid or pet pyjak or something.

Anyway, we can't know anything else.

Case closed !

Turix is in a globular cluster, which can be found anywhere in the galactic halo, i.e. a spheroid region with a radius of about 100 kpc i.e. 326,156.38 light-years. This is significant, because now Turix couldn't just be anywhere on a circle centered on Earth 36,000 light-years across, but anywhere within the corresponding sphere.

GASP !

Okay, hold your horses : globular clusters congregate around the galactic core but above and below the galaxy's disk (where we are), i.e. far from the galactic plane.

A neutron star is what's left after a massive, dying star has exploded into a supernova — the dead, ultra-dense heart of the star. A neutron star is the extremely heavy remains of a star whose escape velocity (i.e. the minimum speed an object must reach to escape the gravity of an astronomical body) is nonetheless lower than the speed of light ; otherwise, what you have is a black hole.

Neutron stars are formed out of main-sequence stars whose initial mass is at least 8 times the mass of the sun, but no more than 40 times the sun's mass (i.e. the bigger B-type and the smaller O-type stars), subsequently increasing as they go through a supergiant phase until the core collapses into a neutron star and the rest of the star explodes into a Type II supernova.

Current models state that a neutron star's maximum mass before it becomes a black hole would be between 2.2 and 2.4 times the mass of the sun.

Turix is a neutron star with several known properties :

Mass : Slightly more than twice Sol's mass

Radius : 15.8 kilometers

It spins ; and it does so at about 24% of light speed.

First of all, we should note Turix is very large and very heavy for a neutron star. As a point of comparison, the pulsar PSR J0740+6620 is as heavy as 2.17 Sol's and a diameter of 24 km (i.e. a radius of 12 km) — and it is one of the most massive neutron stars ever recorded. But Turix is bizarrely large ; it would decrease its density, which might be a problem as neutron stars only exist if they're so dense the atoms of the old star core decay into rows upon rows of tightly-packed neutrons, who'd rather not be this close together, thank you very much. If the star isn't dense enough, the neutrons decay ! But that's clearly not the case here, given how mind-bogglingly massive Turix is.

(Watch me as I completely ignore what's likely to be a dev's mistake and/or comparative lack of scientific information given they only had the information that was on hand in ye year of yore 2010. They probably extrapolated what a really massive neutron star would be like out of what data was available at the time.)

EDIT : A look at the second page of the paper here suggests the radius, while extreme, is perfectly fine for a neutron star ! I stand humbled and corrected.

Moreover, what about that spin ? 24% of the speed of light is 71,950,189.92 m/s, or about 71,950.19 km per second. This means Turix would spin almost over four thousand times per second ! This isn't just a neutron star, but a millisecond pulsar !

Would you believe me if I told you that, in all likelihood, Turix is in fact a real neutron star, the fastest-spinning pulsar known at present in the globular cluster Terzan 5 approximately 18,000 light-years from Earth, spinning at approximately 24% of the speed of light ?

(I bet you didn't expect that plot twist !)

Turix's human name is PSR J1748−2446ad.

As for the Terzan 5 globular cluster, it lies toward the Galactic Center in the direction of Sagittarius and is found in the galactic bulge (i.e. the thickest, central part of the Milky Way), practically on the galactic plane and between Sol and the Galactic Center. In other words, it is…

ABOUT HERE !

Okay. Alright. I want to stress : there is no way on Earth that the dev (Hepler) who sat down to type out the CDN stories in 2010 for ME2 had come up with the regional division of the Milky Way we see crop up for the first time in ME3, and there is no way in hell he had worked out Terzan 5's location and the borders of the regions of the galaxy at the same time. This can't not be a coincidence.

Nonetheless, it's a wonderfully inspiring one.

Because it does look like Turix and the cluster it's at the center of (as an ultra-heavy neutron star, Turix would have naturally migrated to the center of its globular cluster due to mass segregation) is a landmark, a marker that serves as one of the cornerstones of salarian territory.

This would suggest that Turix and Terzan 5 are accessible either from the Serpent Nebula, the Annos Basin, or the Horse Head Nebula. Personally, I'd be a fan of Terzan 5 being accessible from the Annos Basin because the salarian home cluster's got a dearth of branching clusters, but there's no way to know.

(Worth pointing out : while the news story stresses that probes have a hard time getting close to a neutron star, Turix and its whereabouts seem uniquely inhospitable given that radiation filters through the Kappa Iota relay when it's active, to such an extent probes need to be shielded to even approach that relay. But in other circumstances, it is possible to mine "the asteroid debris that orbit neutron stars and pulsars" with the "extensive use of robotics, telepresence, and shielding to survive the incredible radiation from the dead star", alongside the "well-funded collection ships" called "Inferno-class" starships — it is is dangerous and very expensive, but it is possible, whereas even getting close to the relay leading to Turix was something of an (alleged) scientific breakthrough. We can presume the radiation off Turix is so massive because of the pulsar itself, all the densely-packed stars in Terzan 5, and the horrific radiation that's par for the course for the galactic core.)

And there you have it — an additional cluster on the galaxy map*.

1 - How fast are starships in the Mass Effect universe ?

You know me ; the questions we'll be asking are : What's the data in canon ? How can we complicate the picture ?

The major indication we get on FTL speeds is from a comment in ME1, when Ashley reacts to Shepard admiring her for making the trip from the Czarnobóg Fleet Depot to Amaterasu : "It was only a dozen light-years. Like a day's cruise. It's not like I was going to Earth or something." The phrasing suggests people expect to travel more than a day if they're travelling.

Moreover, Ashley tells us that Czarnobóg and Amaterasu are in the same cluster, and what being "a dozen L.Y. away" represents to the average person : "Close enough to talk regularly, too far to make it back in an emergency. I couldn't afford a fast packet flight."

(To keep you from wondering : a packet flight would be a starship travelling at regular intervals between two ports ; historically, a packet boat or a steam packet refers to boats that did so to convey mail from one port to another.) (In a cut ambient conversation from ME1, extracted by @lyricsaboutcats,the salarian businessman Rulamin mentioned trying to get "a packet" from Noveria to Ryskos to a friend, then finding that it won't be possible to get "a packet flight" for at least six days.)

(The mention of a "fast packet flight" suggests that you have a range of options among packet flights : presumably, the faster ones are more expensive.)

To provide a sense of perspective, the Tempest, which benefits from using "several once-proprietary technologies" and "[not] being weighed down by heavy armor or a main gun", has an "average speed" (see below) of 13 light-years per day, making it "easily the fastest ship in her class", i.e. a frigate-sized survey ship. Given that lighter starships can accelerate to greater FTL speeds than more massive ships, with the fastest military ships being frigates, as well as the unique conditions that made the Tempest possible, I find it probable that the Tempest is one of the fastest ships ever made by the current Citadel species. It is certainly faster than the heavier Normandy SR-1 or SR-2.

The Reapers "can travel nearly 30 light-years in a 24-hour period". This is "more than twice the speed of Citadel ships", in keeping with what we've outlined above. In addition, this sets a very hard upper limit : at the moment, there is no Citadel ship which can reach a speed virtually or absolutely equal to 15 light-years per day (which would be exactly half the estimated Reaper speed).

2 - Which starships are the fastest in the Mass Effect universe ?

In canon, there are at least two factors which have an impact on a starship's speed : its thruster type (or how much motive power they can have, given that starships "use their sublight thrusters for motive power in FTL") and its mass (or how much eezo and power is required to move the damn thing).

The Codex is fairly clear that a starship's speed depends on its type and what thrusters it has ; there are "several varieties of thruster, varying in performance versus economy" :

"All ships are equipped with arrays of hydrogen-oxygen reaction control thrusters for maneuvering." Note that those are "liquid hydrogen/liquid oxygen reactions", not gas. From my own research, I found that the exhaust velocity of a rocket flame usually is several thousands of meters per second.

"Ion drives electrically accelerate charged particles as a reaction mass. They are extremely efficient, but produce negligible thrust. They are mainly used for automated cargo barges." The noble gas xenon appears to be the propellant of choice, in keeping with real life, as there is evidence that it is harvested specifically for ion drives on the planets Alingon, Uzin (in the Eagle Nebula), and Venture, and logically elsewhere. Per my research, the exhaust of an ion drive would be an order of magnitude faster than a chemical rocket's.

"The primary commercial engine is a "fusion torch", which vents the plasma of a ship's power plant. Fusion torches offer powerful acceleration at the cost of difficult heat management. Torch fuel is fairly cheap: helium-3 skimmed from gas giants and deuterium extracted from seawater or cometary bodies. Propellant is hydrogen, likewise skimmed from gas giants." If I can trust my own research, the exhaust velocity of a torch drive would supposedly be measured in thousands of kilometers per second.

"In combat, military vessels require accelerations beyond the capability of fusion torches. Warship thrusters inject antiprotons into a reaction chamber filled with hydrogen. The matter-antimatter annihilation provides unmatched motive power. The drawback is fuel production; antiprotons must be manufactured one particle at a time. Most antimatter production is done at massive solar arrays orbiting energetic stars, making them high-value targets in wartime."

Finally, in 2185, some cutting-edge technology like the Helios Thruster Module uses "metastable metallic hydrogen" both as a superior alternative to "liquid H2/O2" reactions powering "maneuvering thrusters", as well as a slower but cheaper viable alternative to antiprotons for "forward impulse".

Since the fusion torch is the primary engine type in the setting by the time ME1 rolls, we can conclude that the fusion torch allows the average Citadel spaceship, including military starships when out of combat, to travel at a cruising speed around 12 light-years per day (24 Earth hours) - "cruising speed" being defined as "the maximum speed at which a vehicle is able to travel continuously and comfortably, without using a large amount of fuel or effort". In other words, starships can in all likelihood reach FTL speeds faster than 12 ly/day, but that isn't meant to happen, as they are not designed for that, and doing so would a) make the trip uneconomical, and/or b) start damaging the ship.

The other significant limit is the mass of the starship, as "[the] amount of eezo and power required for a drive increases exponentially to the mass being moved and the degree it is being lightened. Very massive ships or very high speeds are prohibitively expensive." What is in bold suggests that mass relates to the mass effect field in two ways : it appears that the more massive an object, the harder it is to affect it ; and that the lighter one wants to make an object, the more eezo and electricity one will need.

This is apparent in the various weights of large military vessels : a dreadnought needs to be as long and massive as possible to bring the greatest firepower to bear, resulting in ships ranging "from 800 meters to one kilometer long" and weighing "millions of tons" - but this mass results in low maneuverability and the slowest speed. By contrast, frigates are the lightest and smallest large military starships, the only large vessels "able to land on planets" ; as a result, they "achieve high FTL cruise speeds because of their high-performance drives. They also have proportionally larger thrusters and lighter design mass, allowing them greater maneuverability. In combat, speed and maneuverability make frigates immune to long-range fire of larger vessels."

Given that cruisers appear be to the standard for military starships, balanced between frigates (faster, but with far lower offensive and defensive capabilities) and dreadnoughts (far more destructive and tough, but slower), it may be that most commercial vessels are in the same weight and have access to the same FTL speeds, perhaps slightly faster because of their lack of guns and armor. Thus, I posit that most Citadel starships probably fall close to cruisers when it comes to FTL speeds.

As a logical consequence of the above, some of the fastest ships you could find travelling in the Milky Way would be couriers, as the shortest travel time possible would be vital for their job ; this would be in keeping with the analysis presented here over on Atomic Rockets. We know the galaxy at large relies on "high-speed couriers" when comm buoys aren't available, as well as "diplomatic couriers". However, we know that courier ships aren't substantively faster out of FTL than other ships, since the ship of the Rachni Queen's emissary in ME2 - should you spare the rachni on Noveria - had been a courier's ship which was nonetheless ambushed by pirates and forced to land on an uncharted world.

But it's probable that the very fastest are fighters, whose extremely low mass makes them "capable of greater acceleration and sharper maneuvers than starships". Contrary to what I thought for years, fighters are FTL-capable, as what separates spaceplanes (any vessel that can fly both in an atmosphere and in space) from "true deep-space fighters" is that the former "have no FTL drive".

That being said, this probably doesn't amount to much, since fighters won't be travelling through star clusters. Fighters aren't independent ; indeed, they rely on cruisers and carriers to get them anywhere. This is logical : since you want the lightest possible vessel to reach the highest possible speed, there's probably little in the way of life support or other systems that don't anything to do with getting close to some enemy starship as fast as possible without getting shot down. In other words, fighters are irrelevant when considering how FTL speeds impact the development of clusters.

To sum up :

the cruise speed of Citadel starships is around 12 light-years/Earth day. The Tempest, at 13 ly/day, is exceptional.

this speed of 12 light-years/day is presumably the average speed one can reach with a fusion torch ; starships with ion drives are going to be much slower, because their design concern isn't how fast you can get anywhere but how cheaply.

the less massive a ship, the faster it will be in FTL. Out of military ships, dreadnoughts would be the slowest, while frigates would be the fastest. Because the Tempest is extraordinary for its size, that means the FTL speed of frigates (Normandies included) is probably superior or equal to 12 ly/day and certainly strictly inferior to 13 ly/day.

the fastest starships would be even lighter than the Tempest and only be concerned with speed - the Tempest is built for scientific survey and analysis, as well as long-term habitation. Nonetheless, the Tempest is canonically the fastest ship by far for a ship its size (for the reasons outlined above).

the fastest ships of them all are therefore likely to be fighters, but they are not going to have an impact on the economic development of star clusters because they are not independent. I posit that the fastest after them are couriers, but that's a very specific, somewhat uncommon kind of ship.

basically, you're probably going to find vessels going at different FTL speeds depending on their purpose, with very specialized (and therefore rarer) vessels at the extremes of performance ; 12 ly/day is either the average or the median Citadel FTL speed.

tl;dr : 12 light-years per day is the relevant speed for our purposes.

3 - How fast can starships accelerate ?

3.a : The basics of acceleration in canon

There is an additional consideration which is barely touched upon in canon : the rate of acceleration and deceleration.

In the Codex, we are told this : "Any long-duration interstellar flight consists of two phases: acceleration and deceleration. Starships accelerate to the half-way point of their journey, then flip 180 degrees and apply thrust on the opposite vector, decelerating as they finish the trip. The engines are always operating, and peak speed is attained at the middle of the flight."

(The reason the Codex stresses that engines are always operating is to emphasize that a starship is never moving at a constant speed - because if the goal is to remain in motion, then a starship doesn't need engines, it just needs to keep on drifting. Indeed, in the vacuum of space - i.e. a virtually frictionless environment - a starship in motion stays in motion at a constant speed in a straight line until and unless acted upon by an outside force, sir - AND THAT IS WHY SIR ISAAC NEWTON IS THE DEADLIEST SON-OF-A-BITCH IN SPACE!)

So ! The Codex informs us that a starship is either accelerating or decelerating at any given time, that its engines are always operating, and that its speed therefore constantly varies, with its maximum FTL speed during the journey achieved at the exact middle of the flight.

In the games, this is referenced in an exchange Shepard may have with Marab, the manager of the Saronis Applications store in Zakera Ward, in ME2 (link).

SHEPARD : You know, I use quite a bit of software in my line of work.

MARAB : It's a shame so few understand their own equipment. Besides the most obvious point-and-go nav interfaces anyway.

SHEPARD : You wouldn't believe how often I hear, "Why is the ship turning around ? We're only halfway there !" [MORDIN nods in sympathy.]

MARAB : [He chuckles.] Oh, I would !

In space nerd parlance, this is known as a brachistochrone, while the midpoint flip-over is alternatively called a "skew flip" or a "flip-and-burn" in sci-fi. A brachistochrone is typical of starships with fusion torches, or torchships, which indeed fits with what we've seen, as we've established that fusion torches are the standard thruster type for Mass Effect starships as of 2183. For more information on brachistochrones, let me refer you to the supreme space nerd website, the wonderful and exhaustive Atomic Rockets ; I'll be quoting select excerpts throughout.

tl;dr : Starships are always either accelerating or decelerating, and reach their maximal speed at the exact halfway point of their journey, at which point they turn around and start decelerating. This is known as a brachistochrone.

Corollaries of that piece of information worth stressing include :

if a starship's peak speed is attained at the middle of the flight - e.g. 12 hours in during your 24-hour trip where you'll be travelling 13 light-years - because it takes exactly as much time for a starship to decelerate as to accelerate, then you're also halfway to the destination at the same moment - in our example, 6.5 light-years from your starting point (see also Shepard's exchange with Marab above) ;

however, because that starship is always accelerating (then decelerating), it starts covering very little distance at the beginning of its journey before progressively picking up speed ; this means that at 25% of its travel time, it will not have travelled 25% of the distance. The reverse is also true : at 75% of its travel time, our hypothetical starship will have flown more than 75% of the journey.

Moreover, we know that the initial mass of the starship and its type of drive core (i.e. how much eezo there is in it and how much power they can inject in it) are the hard constraints on how much a ship can accelerate. Again : "Faster-than-light drives use element zero cores to reduce the mass of the ship, allowing higher rates of acceleration. … The amount of eezo and power required for a drive increases exponentially to the mass being moved and the degree it is being lightened. Very massive ships or very high speeds are prohibitively expensive."

Until now, I've talked about starships in terms of which is the fastest ; but really when we are discussing the speed of starships, we are talking about how quickly a starship can change its speed. The size of an eezo drive core relative to the vessel has an impact on the vessel's acceleration : deep-space fighters, for example, "are economically fitted with powerful element zero cores, making them capable of greater acceleration and sharper maneuvers than starships" (Source : Codex : Starships: Fighters). For the other military vessel types, frigates, which can achieve "high FTL cruise speeds", would have the second-fastest acceleration, followed by cruisers, with carriers and dreadnoughts dead last.

tl;dr : Talking about a starship's "average speed" or "cruising speed" doesn't mean much because what really matters is how much it can accelerate. Lighter starships can achieve greater acceleration.

So, uh, I have to address some things about acceleration in physics.

OH BOY HERE COMES THE INTERLUDE

Interlude : A genteel Reminder on Fundamentals of Acceleration

The speed of an object is a measure of how much distance it travels (change in position) over time ; the velocity of an object is its speed alongside the direction in which it moves. Both speed and velocity are usually noted v, and both are measured in meters (for distance) per second (for time), or m/s. You will note that "12 light-years per day" is a measure of speed, since it is expressed by units of distance ("light-years") and time ("day"). In SI base units, that should be (if I can calculate) 1.314e+12 m/s, or 1.31 trillion meters every second ; as the speed of light in vacuum (c) is exactly 299,792,458 m/s, I'll note that the cruise speed of a starship is about 4380 times the speed of light in vacuum, or 4380 c.

Acceleration is any change in the speed or direction (or both) of an object in motion ; from the point of view of physics, deceleration is acceleration. Acceleration is noted a ; since it measures the change of speed and/or direction over time, it is measured with the unit of velocity (m/s) divided by the unit of time (s), or meters per second per second (or (m/s)/s), which mathematically entails that it's the same as meters per second squared, or m/s^2.

Another unit which is going to be very useful soon is g (not to be confused with "G" [the gravitational constant] or "g" [that's grams]). g is another unit of acceleration, measuring the standard acceleration due to Earth's gravity, i.e. how much the gravity of Earth causes an object near the surface of Earth to steadily gain speed (i.e. accelerate) in a vacuum - that is to say, in a context where the only force acting upon that object is Earth's gravity. g is a constant defined as 9.80665 m/s^2 ; in Mass Effect, you probably know it because, on the data description for every single planet, g is used as the unit of gravity, with Earth as the standard at 1 g.

In classical mechanics (i.e. the Newtonian equations that don't involve anything starting to try to get close to the speed of light, since the closer you get to it, the more Einstein starts to mess with your stuff ; by convention, the threshold is 0.14 c), the sacrosanct equation is F = m*a (or a = F/m), where F is the net balance of all forces acting on an object, m is the object's mass, and a is its acceleration (quoth Wikipedia). In plain English, the more acceleration you want, the more force you'll need (and that is Sir Izzy's Second Law of Motion) - something you're likely to have experienced if you have ever ridden a bike, for example : your top speed is limited by how much energy you can pour into your pedaling (and friction, thankfully virtually absent from the deadly vacuum of space, is always slowing you down).

Now, to prepare yourself for what's to come, I'll also note two things :

in the context of spaceflight, acceleration is equal to rocket thrust divided by starship mass (a = F/Mc, where F is the starship's thrust measured in Newtons (N), i.e. in kg*m/s^2 ; and Mc is the starship's mass at a given point in time measured in kg) ; because the mass of a starship decreases during its flight as it expends propellant and fuel, any equation trying to calculate the acceleration of a spacecraft will have to take that variation into account.

also relevant to our talking about mass and acceleration is inertia, i.e. the phenomenon in the deadliest son-of-a-bitch in space's First Law of Motion described above, i.e. how tough it is to change the speed of any object (such as setting an object at rest in motion), i.e. how tough it is to accelerate (or decelerate) anything. SPOILERS : inertia is dependent on mass, because the more massive an object, the harder it is to accelerate it, and the more energy will be required to do so (drop a rock and a sock, try rolling them forward on the floor ; one is significantly easier to move than the other). A consequence of this is that it requires increasingly ludicrous quantities of energy to accelerate any object with mass to a velocity close to the speed of light (c), and it would require an infinite amount of energy to accelerate any object with mass to c ; it's only because light is virtually massless that it can get to c in the first place.

But that's not a problem when you have magical eezo allowing you to travel faster than light without any physics-breaking consequence !

Thus endeth the Interlude.

The Interlude Has Ended - please return to your seats

All of that is important because all starships have an upper limit to how fast they can go, a maximum speed past which they can no longer accelerate (at which point the sensible thing is to turn off the engines), perhaps even the same speed in starships of different weight classes, for all we know ; but crucially, some starships can reach that top speed much faster than others.

So, uh, how much acceleration can the starships in Mass Effect (and the squishy people inside) take ? Well, we know that large ships like cruisers and dreadnoughts actually rely on constant acceleration to simulate gravity : "Mass effect fields create an artificial gravity (a-grav) plane below the decks, preventing muscle atrophy and bone loss in zero-gee. Large vessels arrange their decks perpendicular to their thrust axis. The "highest" decks are at the bow, and the "lowest" at the engines. This allows a-grav to work with the inertial effects of thrust. Ships that can land arrange their decks laterally [i.e. frigates and smaller vessels], so the crew can move about while the vessel is on the ground."

This is achieved because acceleration can effectively simulate gravity, what is known as the equivalence principle : inertia "pulls" you in the direction opposite that of the vehicle's motion (think about how your body is pulled back when the car or public transport you're in starts moving forward, whereas you're thrust forward if the same vehicle brakes suddenly). In effect, if you are in a vehicle accelerating at 9.80665 m/s^2, i.e. 1 g, every object within that vehicle behaves as if they were on Earth, "falling" toward the back of the vehicle.

That is what the larger starships rely upon : presumably to avoid spending power (thus fuel, thus money) on a-grav, Alliance cruisers or dreadnoughts, for example, need to be constantly accelerating at 1 g to simulate Earth's gravity, never changing that acceleration because it would change the pseudo-gravity.

tl;dr : The heavier starships use acceleration to simulate gravity. This means even the heaviest Alliance starships can reach at least 1 g of acceleration. Because lighter starships are capable of greater acceleration, they are also able to accelerate to at least 1 g.

(By the by, this suggests that whereas frigates like the Normandy may have thrusters which can fire in opposite directions to accelerate and decelerate, the larger starships do need to physically "turn around", otherwise "gravity" would shift and stick them to the ceiling ; if such a starship doesn't "park in reverse" when it leaves FTL, as it does in cutscenes (for example when Hackett's ship arrives guns first in ME3), this suggests in turn that its engines are killed, stopping any deceleration, and that the starship then turns around a second time before switching off FTL.)

The problem of course is that starships need to be accelerating much, much faster to achieve the range that has been observed in the OT : at a constant acceleration of 1 g, a starship would cover 9,144,576,000 meters in 12 hours, i.e. 9,144,576 km, i.e. 0.00000000000095 light-years - and twice that over 24 hours if we assume this is a brachistochrone, or 0.0000000000019 light-years - a very far cry from 12 light-years.

Now, there are some things we should keep in mind :

there's all the timey-wimey handwavium stuff related to FTL travel in Mass Effect ; it appears that there is a difference between the speed of the starship as perceived within the envelope by aboard observers (the subjective speed) and the speed of the starship as perceived outside the envelope (the "objective" speed). FTL is a can of worms best left unopened, but suffice to say 1 g will, in all likelihood, allow a starship within an FTL envelope to travel faster and farther than it would under normal circumstances.

there's also the hard limits of engineering : to maintain a continuous acceleration, i.e. to keep going faster and faster, the starship is going to need more and more thrust, thus more energy, which will be harder to provide and start taxing the ship at some point. Now, Atomic Rockets kindly informs me that a torchship is just about the only ship type which can manage constant acceleration, but nonetheless, there's going to be an upper limit at some point. This in fact appears to be a non-issue ; after all, the Codex takes it as a given that a starship never stops accelerating. I'd argue this is likely because of how the Mass Effect franchise enjoys the benefits of the, uh, mass effect : if the starship's mass is decreased as it accelerates, then no additional energy may be needed, and continuous acceleration may just be maintained.

and then of course we need to talk about inertial dampeners.

3.b : Inertial dampeners

Inertial dampeners, also known as inertial dampers, inertial compensators, inertia compensators, internal compensators, acceleration compensators and many, many other things, are a mainstay of science-fiction, as they're the piece of technology which explains why everyone inside a starship isn't crushed to a pulp by their acceleration to truly plaid ludicrous speeds.

Their effect can be inferred in Mass Effect every time we're aboard the Normandy (a ship whose active artificial gravity isn't aligned to its thrust but perpendicular to it) and we don't see the crew thrust toward the engines screaming for their lives whenever the ship is flying. In text or dialogue, the earliest reference I could find was in some of Joker's ambient dialogue in ME2 when you come to the bridge : "Sometimes I get the urge to turn off the internal compensators and pull a Crazy Ivan, you know ?" (i.e. he wants to yaw 180° with full inertia to send people and small objects flying).

But the technology got the spotlight during the Citadel DLC if you spend some time with Steve, where he demonstrates what happens when you turn off the inertial dampeners in the Kodiak shuttle :

CORTEZ : Before mass effect fields, there was no such thing as inertial dampeners.

SHEPARD : Yeah ?

CORTEZ : Here, feel this.

[The Kodiak roars to life and elevates off the landing pad. SHEPARD stumbles and falls into his chair.]

SHEPARD : Whoa.

CORTEZ : That, my friend, is unadulterated momentum. Want to really feel it ?

[If "Go for it" is selected.] SHEPARD : Show me.

[The Kodiak goes up and down and does a barrel roll. CORTEZ and SHEPARD's bodies move with the momentum, through they remain in their seats despite the lack of visible seatbelts. SHEPARD hoots and laughs.]

CORTEZ : See ? Doesn't take much to pull a few [g's].

[If "Keep it steady" is selected.] SHEPARD : You can turn those dampeners back on anytime.

CORTEZ : Okay, okay. Doesn't take much to pull a few [g's], and we don't want to paint the windows with your breakfast, right ?

[End of branching conversation] CORTEZ : Back in the day, pilots would wear G-suits. It squeezes your body so that the blood stays in your head in tight maneuvers. I'd wear a G-suit flying my Trident. In a fighter it's common to transfer power from the inertial dampeners to other systems.

Here is how inertial dampeners are relevant to the conversation about acceleration simulating gravity : presumably, a cruiser or a dreadnought can accelerate at a rate much higher than 1 g and still use its inertial dampeners to compensate that acceleration and simulate 1 g regardless of its actual acceleration, as long as it is in excess of 1 g. This is very nice, because human beings tend to die at some point after 4 g.

In-universe, this is logical and worthwhile as it allows a spaceship to turn off its artificial gravity and use its inertial dampeners less, instead of nullifying 100% of the effects of acceleration and wasting power on a-grav.

tl;dr : Inertial dampeners can be and probably are used to make starships accelerate at rates far superior to 1 g.

(How mass effect fields make inertial dampeners work is entirely speculative and quite beyond the purview of this very long post. Likewise, whether negating inertia has an impact on Newton's First Law of Motion and the object in motion staying in motion is beyond me, though I should note that neither the games nor the Codex show anything that would suggest this law is altered.)

3.c : What factors in a starship's acceleration ?

So let's say I am Joker and that I have a spaceship. When I want to go anywhere, I light up my thrusters to get going, i.e. accelerate ; I use eezo and the mass effect to lower my spaceship's mass to accelerate even more without changing my thrust ; and I use my inertial dampeners to survive enormous acceleration, the type of acceleration which would otherwise purée me and anyone made of pulpy meat.

Is there something else we can surmise about a starship's acceleration ? Yes. Yes, I think we can.

You see, we might expect how much a starship accelerates to depend on the variously varying variables of an individual journey : after all, sometimes you may want to get somewhere as fast as you can, whereas sometimes using as little propellant and fuel as you can and making the journey less expensive are your top priorities. The problem is that muddles what might be plausibly considered everyone's highest acceleration.

Luckily for us - and unfortunately for everyone else - in Mass Effect 3, we know how fast everyone is moving during the Reaper War, when everyone's priority is either a) get somewhere as fast as you can because you are a warship and time is of the essence, or b) get somewhere as fast as you can because eldritch starships from the depths of dark space want to kill you and everyone you love ; either way, everyone wants to get anywhere as fast as technologically possible, i.e. at a speed less than half the speed of the Reapers ; as we've seen, this fits with the idea that a Citadel ship with a torch drive is moving at 12 ly/day, accelerating then decelerating from the midway point.

This means that the range of 12 light-years in a single day is in all likelihood what a Citadel spaceship can achieve when it is moving at the maximum acceleration it can generate, because maximum acceleration is what will allow a starship (or anything) to get anywhere as fast as possible. A corollary of this is that we understand that Citadel spaceships are always moving at maximum acceleration in all circumstances, including in times of peace. Remember this : this will be relevant later.

Complicating matters is that we (ugh) have to get into the specifics of FTL travel. As I've said before, the crux of what we know is in this phrase : "Faster-than-light drives use element zero cores to reduce the mass of the ship, allowing higher rates of acceleration. This effectively raises the speed of light within the mass effect field, allowing high speed travel with negligible relativistic time dilation effects."

The problem is that there can be no causal link between the two sentences above, not with the way they are presented. Logically, we appear to have two discrete effects instead :

if, theoretically, a starship's mass is reduced to 0 kg, i.e. is made mass-less (and we don't know if the technology can do that), then this does allow "higher rates of acceleration" - but only up to the speed of light. You can't go faster than light if you have no mass because light, which has no mass, can't - that's why it's called the speed of light. (Before someone says anything : There's nothing in canon which suggests negative mass is involved, and we don't even know what negative mass would be beyond a number in an equation.) But in any case, the lighter a ship becomes, the less energy it will need to accelerate. That's your bog-standard mass effect, or Effect #1.

then something else happens that "effectively raises the speed of light" within the envelope, which allows for FTL travel relative to the universe outside the envelope, but presumably never going past lightspeed within the envelope. That's Effect #2.

So it appears that "how much a starship can accelerate" and "how far the speed of light is raised" are separate phenomena but which are difficult to distinguish (let alone to see how they relate together) from an outside perspective. There's going to be a difference between the spaceship's perspective on its acceleration from inside the envelope, and everyone else's perspective on the spaceship's acceleration from outside the envelope.

We can actually safely assume that a starship doesn't lower their mass all the way to 0 kg and get to lightspeed at any point of the journey, even subjectively, because if they did that they would just turn off the engines - and we know that a starship never coasts, they just keep on accelerating (this always was very likely because if you reach the speed of light, time effectively stops for you, but there's no way to know if Mass Effect writers know that and take that into account). This probably tells us something about the limits of mass effect fields and the associated technology : it might just take exponential power to get to pure masslessness - perhaps even infinite power.

So, to sum up : a spaceship's maximum speed is dependent on maximum acceleration - because if they're no longer able to accelerate then they just turn off the engines and drift. A spaceship's maximum acceleration, in turn, will be dependent on :

its thrust ;

how much its drive core can lower its mass ;

and how much its inertial dampeners can cancel out its acceleration's effects on the squishy crew.

(Note that if you increase one, you don't have to increase the others. If you lower your mass, you will start accelerating without increasing your thrust or demanding more of the inertial dampeners. The inertial dampeners come into play when you're undergoing accelerations that would be putting your starship on a high-gravity world.)

We've already established that, in any context, the current generation of Citadel starships in the 2180s is always traveling at the maximum acceleration they're capable of, i.e. what gets a starship at FTL to travel 6 light-years in 12 Earth hours from an initial state of rest.

We can also deduce that it takes more than 12 Earth hours for a starship to reach the point where they wouldn't be able to pile more energy to keep accelerating. Otherwise a spaceship would accelerate in as little time as possible to their top speed, then turn off its engines and its inertial dampeners to make huge savings as it drifts at constant speed (there ain't no friction in space after all).

Another corollary is that, at 12 light-years per day, a starship's mass is lowered and a starship's inertia is dampened as much as the starship can without risking its integrity and the lives of everyone aboard - we might speak of "cruising mass-lowering" and "cruising inertia-dampening" to reach "cruising acceleration". In other words, I think it's safe to assume that, since a spaceship would be undergoing cruising acceleration, i.e. the highest acceleration it can provide at all times without damaging itself or endangering its crew, then its inertial dampeners would be handling at all times the maximum acceleration they can safely take.

"Please, crapeaucrapeau," I hear a fictional stand-in for the reader hypothetically whine, "I can't take it anymore, just stop talking about acceleration." Ah, but dear long-suffering reader, the reason I'm doing all this is that, while we've established that starships in Mass Effect are always in continuous acceleration, the fact they appear to be actually always going at their maximum acceleration entails that they are also moving in constant acceleration.

And that's interesting because we can actually get actual numbers from that.

3.d : Constant acceleration

If a starship is always moving at the maximum acceleration it can reach, then it's undergoing constant acceleration, i.e. a rate of acceleration that remains the same throughout the duration of the flight. The longer a starship flies, the faster it gets.

I should point out that Mass Effect, in keeping with its original hard science-fiction ambitions, is once more entirely coherent with the science and science-fiction it pilfers is influenced by : every single article I've read suggests that constant acceleration is indeed what anyone with a starship able to do brachistrochrones would be doing.

Constant acceleration (which we need, even with inertial compensators) leads to a speed which is proportional to that acceleration ; hence why it's assumed by everyone who mentions it in the OT that it always takes exactly as much time to decelerate as to accelerate.

We actually can squeeze what is our average 12-light-years-per-day starship's constant acceleration out of the data, focusing only on a single burst of constant acceleration during the initial half of that journey :

its initial time - t0 - is when it starts moving, i.e. 0 seconds, i.e. 0 hours, i.e. 0 days ;

its initial velocity - v0 - is how fast it is at t0, i.e. 0 ly/day or 0 m/s^2, since it is at rest relative to the frame of reference ;

its final time - t - is at the midpoint of the entire journey, i.e. 12 hours, i.e. 0.5 day, i.e. 43,200 seconds ;

its average velocity is 12 light-years per day, since it has covered 6 light-years in 12 hours ;

therefore, at constant or uniform acceleration for the duration of the flight, its final velocity - v - will be twice its average velocity, or 24 ly/day.

Assuming that this starship's acceleration - a - is constant, then its average acceleration is the same as its acceleration at any point of its journey ; therefore, a starship's acceleration can be calculated first by subtracting the starship's initial velocity from its final velocity, or v - v0 ; then by dividing the result by the starship's final time, i.e. t.

In other words : a = (v - v0)/t ; and therefore v = v0 + a*t

In our example, v - v0 = 24 - 0 = 24 ly/day = v ;

and a = v/t = 24/0.5 = 48 ly/day^2.

(Of course, the constant acceleration for the other half of the journey - the decelerating part - would be -48 ly/day^2.)

Now, if we put those results in SI units : we need to change "days" to "seconds" as the unit of time, and "light-years" to "meters" as the unit of distance. As a reminder, there are exactly 9,461,730,472,580,800 meters in a light-year, or 9.46 quadrillions.

If v = 24 ly/day, then it's equal to 227,064,000,000,000,000 m/day (or 227.1 quadrillion m/day), which is equal to 2,628,055,555,555.56 m/s (or 2.6 trillion m/s).

If a = v/t = 48 ly/day^2, then it's equal to 2.6 trillion m/s divided by 0.5 day, or 2.6 trillion m/s divided by 43,200 seconds, or 60,834,619.3 (m/s)/s (that's 60.8 million (m/s)/s).

To check if we are correct, a*t should equal v ; or 60.8 millions multiplied by 43,200 should equal 2.6 trillions — which is indeed the case.

Note that this is the starship's constant acceleration as measured by a stationary observer outside the envelope : within the envelope, where an observer is not measuring any speed that is superior to the speed of light in a vacuum, the values would be much lower, and the corresponding energy required to generate that acceleration would also be lower.

(Yet another piece of circumstantial evidence in favor of constant acceleration is that the fact the average distance covered by Citadel starships in the OT becomes comparable to the Tempest's average speed in ME:A actually makes sense : with constant acceleration, average speed is equal to range/distance travelled.)

3.e : Putting it all together

So, if we keep in mind a maximum and constant acceleration of 48 ly/day^2, here is what the average velocity/range of a starship for a full brachistochrone would look like depending on time :

One minute : 30 seconds acceleration, 30 seconds deceleration - 30 seconds being 1/2880 of a day, 0.000347 day. If a = v/t, then v = a*t ; 48*0.000347 = 0.016667 ly/day for final velocity ; its average velocity, in a constant acceleration situation is, v/2, or 0.0083335 ly/day. To calculate the final position of the starship at the mid-point of the flight (x), one must multiply average velocity (here, 0.0083335) by t (here, 0.000347) ; the result is 0.00000289 ly. Double it, and you have the full length of the minute-long FTL brachistochrone, or 0.00000578 ly, which is about 0.365526 AU, or 54,681,895.93 km.

Five minutes : 2.5 minutes accel, 2.5 minutes decel ; 2.5 minutes is 0.001736111 days. Now, wonderfully, the way the math works, you can simplify the equations by multiplying v (final velocity) by t (time) to get the final result. v = 48*0.001736111 = 0.083333328 ; 0.083333328*0.001736111 = 0.0002 ly, which is about 9.1495 AU (far greater distance than the distance between the Earth and the Sun, at 1 AU, though still short of the average distance between Earth and Jupiter).

Ten minutes : 5 minutes accel, 5 minutes decel ; 5 minutes is 0.003472222 days. v = 48*0.003472222 = 0.166666656 ; 0.166666656*0.003472222 = 0.0006 ly, which is about 36.5971 AU (an enormous distance, but a bit short of the average distance between Earth and Pluto at 39.5 AU ; keep this in mind, this will be relevant later).

Fifteen minutes : 7.5 minutes accel, 7.5 minutes decel ; 7.5 minutes is 0.005208333 days. v = 48*0.005208333 = 0.249999984 ; 0.249999984*0.005208333 = 0.001 ly, or about 82.3434 AU (greater distance than the average distance between Earth and Jump Zero).

Thirty minutes : 15 minutes accel, 15 minutes decel ; 15 minutes is 0.01041667 days. v = 48*0.01041667 = 0.50000016 ; 0.50000016*0.01041667 = 0.005 ly, or about 329.37 AU.

One hour : 30 minutes accel, 30 minutes decel ; 30 minutes is 0.02083333 days. v = 48*0.02083333 = 0.99999984 ; 0.99999984*0.02083333 = 0.02 ly, or about 1317.49 AU.

Two hours : 1 hour accel, 1 hour decel ; 1 hour is 0.04166667 days. v = 48*0.04166667 = 2.00000016 ; 2.00000016*0.04166667 = 0.08 ly, or about 5269.98 AU.

Three hours : 1.5 hours accel, 1.5 hours decel ; 1.5 hours is 0.0625 days. v = 48*0.0625 = 3 ; 3*0.0625 = 0.19 ly, or about 11,857.45 AU

Six hours : 3 hours accel, 3 hours decel ; 3 hours is 0.125 days. v = 48*0.125 = 6 ; 6*0125 = 0.75 light-years.

Twelve hours : 6 hours accel, 6 hours decel ; 6 hours is 0.25 days. v = 48*0.25 = 12 ; 12*0.25 = 3 light-years.

1 day : 12 light-years (duh) ; v = a*t = 48*0.5 = 24 ; v/2 = 24/2 = 12 = Average velocity ; x = 12*t*2 = 12*0.5*2 = 12

As you can see, the distance travelled increases exponentially to the time spent travelling. Note that the above numbers do not take into account minutiae like any trajectory other than a straight line, or the time when, presumably, the engines are switched off, the starship does a skew flip, and the engines are reignited.

Now, theoretically, assuming that starships can accelerate indefinitely and don't need to stop to get fuel/radiate heat/discharge drive charge/etc…

2 days : 48 ly ; v = a*t = 48*1 = 48 ; v/2 = 48/2 = 24 = Average velocity ; x = 24*1*2 = 24*2 = 48

3 days : 108 ly ; v = 48*1.5 = 72 ; 72/2 = 36 ; x = 36*1.5*2 = 108

4 days : 192 ly ; 48*2 = 96 ; 96/2 = 48 ; x = 48*2*2 = 192

5 days : 300 ly ; 48*2.5 = 120 ; 120/2 = 60 ; x = 60*2.5*2 = 300

But we can pretty much guess that's not the case, or the mass relays would be obsolete.

Going forward, our concerns are :

what are the non-mathematical limits to constant acceleration in FTL ?

And do whatever pieces of information we have about travel time and distance travel in Mass Effect agree with the numbers I've figured out ?

And oh, gosh, I've run out of letters again, I'll have to split this post in twain.

UP NEXT (eventually) : Camala ! Drew Karpyshyn ! Hawking Eta ! Oh, and every data point on speed and travel time in canon. Plus, all those nice numbers I calculated are shown to be… pointless. Fun !

G2HGE Index :

Post 0 : Presentation and Purpose

Post 1 : Methodology and general lamentation over the incoherent state of the lore.

Post 2a : Oldest canon date for activity in every single cluster

Post 2b : Organization and Visualization of the above

Post 3 : The oversized impact of the asari, and a surprising amount of stuff to discover.

Post 4 : The Problem with the Galaxy Maps

Post 5a : The Regions of the Milky Way : Overview and Council Space

Post 5b : The Regions of the Milky Way : The Terminus Systems

Post 5c : The Regions of the Milky Way : The Attican Traverse and Earth Systems Alliance Space

Post 5d : The Regions of the Milky Way : The Nemean Abyss and the Perseus Veil

Post 5e : The Regions of the Milky Way : The Skyllian Verge

4 - The Problem of the Skyllian Verge

Fig. ? : Where is the Skyllian Verge ? Also not on this map.

The Skyllian Verge is a region of space which was claimed by both the Batarian Hegemony and the Systems Alliance ; this contested region single-handedly drove the conflict between the humans and the batarians, culminating with the batarian-sponsored Skyllian Blitz in 2176 and the Alliance’s retaliation on Torfan in 2178, after which “the batarians retreated into their own systems, and are now rarely seen in Citadel space.”

To go into more details, “In the early 2160s, the Alliance began aggressive colonization of worlds in the Skyllian Verge, much to the dismay of the batarians who had been developing the region for several decades. In 2171, the batarians petitioned the Council to declare the Verge a "zone of batarian interest". The Council refused, however, declaring unsettled worlds in the region open to human colonization.” And then what the “proxy war” between the Alliance and the Hegemony starts in earnest.

It’s a remarkably dangerous and lawless region, with slavers and pirates a constant threat. Moreover, all three big mercenary groups started out or were very active in the Skyllian Verge :

the Blue Suns “were initially a Skyllian Verge protection racket” “providing genuine protection from slavers and pirates” and by 2185 CE had expanded to “dozens of planets in Citadel space, the Verge, and the Terminus Systems.”

Eclipse is “embraced” as “a ‘proactive’ security company” in the Skyllian Verge as well as the Terminus Systems.

the Blood Pack started out as “a small Terminus Systems vorcha gang” until it was acquired and “transformed” by exiled battlemaster krogan Ganar Wrang into “a pirate crew”. “Wrang cultivated recruits and infamy for a decade before incorporating his fighters as a security company across the Skyllian Verge. His notoriety ensured his initial public offering for investors made him rich beyond most krogan's dreams. Wrang returned triumphantly to his clan, rallying elders, krogan hordes, and their firepower and biotic support toward professional violence in the Terminus Systems.”

On a completely unrelated note, it’s very interesting to see how each of those three groups is treated in Citadel Space : the Blue Suns seemingly operates there without problems, Eclipse is viewed with suspicion but the Blood Pack is the only one to be outright banned.

Beyond the obvious - the Skyllian Verge is on the borders of the Batarian Hegemony, it’s even why it’s called a “Verge”, but starting in 2157 CE it also was on the borders of the Alliance and things heated up - it’s actually surprisingly difficult to say what is or isn’t the Skyllian Verge. I’m going to do a quick timeline of what I’ve personally been calling “the Cold War* of the Verge”, organizing together every element on the Skyllian Verge I could find, and then I’ll tackle the meaty part : what is and isn’t the Skyllian Verge on the map ?

* : It sounded appropriate, given that this nearly twenty-year-long conflict with enormous geopolitical consequences did not involve a single pitched battle between the Systems Alliance and the Batarian Hegemony, with the Batarian Hegemony avoiding direct confrontation throughout the duration of the period. “Officially there is no war, but neither is there any peace.” The closest those two came to full-on war was after the destruction of the Bahak system either by Commander Shepard or an Alliance strike team - only the sudden Reaper invasion deescalated the situation.

Timeline of the Cold War of the Verge (including events not taking place in the Skyllian Verge but relevant to the conflict) :

since 2140 CE at the very latest, probably earlier : the Batarian Hegemony begins to develop the region of the Skyllian Verge (Source : “for several decades”)

2154 CE : The Batarian Hegemony settles Camala in the Kite’s Nest, the batarian home cluster.

2157 CE : First Contact War between the humans of the Systems Alliance and the Turian Hierarchy

2160 CE :

The Systems Alliance forms its Parliament.

The Systems Alliance founds its first colony in the Skyllian Verge : Elysium, in the gateway system of the Petra Nebula. This absolutely infuriates the Batarian Hegemony.

in the 2160′s : The Systems Alliance embarks in a “pirate suppression campaign” in the Attican Traverse. (relevant eventually for the Skyllian Blitz)

2161 CE : The Systems Alliance and the Batarian Hegemony both claim Aratoht, in the Bahak system (Viper Nebula), “like several planets in the Verge”. The political battle between the batarians on the one hand and the Citadel Committee on Habitable Worlds would last a year*.

2162 CE :

After Jon Grissom and a team of specialists visit Aratoht and conclude that it’s a terrible garden world, the Alliance stops pressing its claim to Aratoht.

The Batarian Hegemony colonizes Aratoht.

2163 CE : The “Leviathan of Dis”, what is in fact a billion-year-old Reaper corpse, is found at the bottom of a crater on the surface of the planet Jartar (Dis system) by a batarian survey team. The dead Reaper “disappears” after a Reaper dreadnought passes by, and the Batarian Hegemony steadfastly denies the existence of the Leviathan of Dis. (Source for the date : “twenty years ago” in ME1, i.e. in 2183 CE).

2165 CE : The Citadel Council grants the Alliance the right to establish an embassy on the Citadel, only 8 years after first contact.

2166 CE : Cerberus purchases Haribon Military Industries on Terra Nova. While it makes legitimate arms contracts with colonial forces, it starts producing models without serial numbers for the express purpose to sell them to crime syndicates in batarian space and the Terminus Systems.

2167 CE : The Systems Alliance settle Therum, in Artemis Tau. (While I’ve never read anything saying outright that Artemis Tau was or wasn’t in the Skyllian Verge, I’m including that event in light of Post 5c, where we saw that Artemis Tau is technically in batarian space on the Galaxy at War map.)

2170 CE : Batarian slavers attack the human colony of Mindoir, “on the fringes of the Attican Traverse.” The event is important enough in the collective memory of the Alliance to warrant an entry in “Codex : Timeline.”

2171 CE :

The Batarian Hegemony officially petitions the Citadel Council to declare the Skyllian Verge a “zone of batarian interest.”

The Citadel Council eventually refuses, “declaring unsettled worlds in the region open to human colonization.”

“In protest, the batarians [close] their Citadel embassy and [sever] official diplomatic relations with the Council, effectively becoming a rogue state. They [instigate] a proxy war in the Verge by funneling money and weapons to criminal organizations, urging them to strike at human colonies.”

2173 CE : Alliance marines engage with and defeat Hegemony (?) soldiers in the Exodus Cluster.**

At some point between 2163 and 2175 CE : An Alliance black ops team, led by Illuminated Primacy hanar operatives, raids a batarian research station, where the Hegemony is studying Reaper technology. The Alliance raid turns into a massacre, the black ops team fakes a power failure to hide the incident. Fortunately, the Alliance does not acquire any Reaper technology ; unfortunately, the hanar operatives do.†

2175 CE : Alliance marines engage in tactical reconnaissance in the Kite’s Nest.

2176 CE :

The turian criminal Elanos Haliat, the most powerful Terminus Systems pirate at the time, uses his influence to assemble an enormous fleet to sack Elysium, “the largest human colony in the [Petra Nebula]” and “drive [humanity] out of the Skyllian Verge”. In 2183, Haliat would describe himself as “the motivator … the instigator”. (Source : Elanos Haliat’s dialogue) This “massive coalition force of slavers, crime syndicates, and batarian warlords” was funded by the batarians. The Skyllian Blitz is the culmination of the exacerbated tensions in the region : the Alliance had made enemies in both the various pirates haunting the Attican Traverse (with its piracy suppression campaigns) and the Batarian Hegemony, which by this point had been funneling money to those pirates for five years. It’s a spectacular victory for the Alliance. After the Blitz fails, Haliat is blamed for its failure and loses the status and prestige he had once commanded over the Terminus pirate bands.

The Alliance starts a “long and bloody campaign to rid the Skyllian Verge of batarian slavers and other criminal elements”.

Perhaps relatedly, the Anhur Rebellions begin. While far away from the Skyllian Verge, the civil war opposes human opponents to slavery and the batarian-backed Na’hesit faction.

2178 CE :

The Alliance sets up a network of covert sensing devices on the moons of the gas giant Theshaca. Recordings of pirate FTL exit vectors over the course of six months lead the Alliance Navy to eight major pirate anchorages, during a series of assaults known as the "Theshaca Raids”.

The “final battle” of the Alliance’s campaign against pirates in the Skyllian Verge takes place on the desolate moon of Torfan, “long used as a staging base by batarian-backed criminals.” At Torfan, “an Alliance fleet wipes out an army of slavers”, though since the “slaver base [was] built miles below the surface of [the] moon … [the] superiority of the human fleet was wasted in the assault on the underground bunker. … [A] corps of elite ground troops [went] into the heart of the enemy base” and engaged in “vicious close-quarters fighting.” Though the Alliance took heavy losses, “not a single slaver made it out of Torfan alive.”

Torfan is effectively the end of the Cold War of the Verge, the point after which “the batarians [retreat] into their own systems” to the point they are seldom seen in Citadel Space afterward.

Perhaps relatedly, the Anhur Rebellions also end that year, with the victory of the anti-slavery Anhur People’s Liberation Army over the batarian-backed Na’hesit.

After 2178, the only major incidents between the humans and the batarians will be the attempted destruction of the Terra Nova colony by Batarian Hegemony Special Intervention Unit agent Balak in 2183 CE - that is, until the destruction of the Bahak system in early 2186.

Very interestingly, if you speak to “Lord” Darius in his base on Nonuel (Plutus system, Hades Gamma), he will tell you this : “You see this gun ? This is your gun. Your military set me up here … After the batarians were driven out of the Verge [i.e. after 2178], the Alliance wanted to stabilize the region. I had the strongest syndicate in the area. They gave me the weapons and money I needed to take over.”

Also worth noting that we can pretty much jot down the Hades Gamma cluster as being in the Skyllian Verge. If the above was not enough, in the mission brief Hackett says, “There’s a criminal leader named Darius in the Skyllian Verge who controls most of the raider activity. I’d like you to negotiate a ceasefire with him.”

* : This last element is canonically debatable - “apocryphal” or “indexed”, I guess. Prior to the release of the Arrival DLC, there was a leak, which included the planetary description of Aratoht which is roughly identical to what we get in game and was archived on the wiki, but with a few differences. However, nothing in the leak contradicts the description in the final product - why change it ? I suspect the description of Aratoht was edited because it was too long : in the leak it’s two paragraphs long, whereas it’s only one in the final product. To give you an idea…

Official description : ““Like Mount Everest inside an oven," was how Jon Grissom described Aratoht while on a fact-finding mission to see if the garden world was worth contestation with the batarians. His team ultimately decided that the planet's air pressure and oxygen content were too low for large-scale human habitation. Undeterred, the Batarian Hegemony colonized the planet's polar regions and began an extensive terraforming effort with cyanobacteria and invasive plant species. Alliance intelligence has confirmed that the colony has several batarian military installations, which are too close to human space for the Alliance's comfort.

“EDI'S TRAVEL ADVISORY: The Batarian Hegemony considers any presence of Alliance military vessels in batarian space as hostile. The Normandy SR2, while an independent vessel, strongly resembles the Normandy SR1, an Alliance ship. Use of stealth systems is highly recommended.”

Previous, leaked description : “"Like Mount Everest inside an oven," was how Jon Grissom characterized Aratoht while on an Alliance fact-finding mission to see if the garden world was worth contestation with the batarians. His team ultimately decided that the planet's air pressure and oxygen content were too low for large-scale human habitation, ending a year-long political battle with the batarians and the Citadel Council's Committee on Habitable Worlds. Since then, the Batarian Hegemony has quietly colonized the planet's polar regions, where the heat is manageable due to heavy rainfall. “Information on the colony itself is restricted by the Hegemony's Department of Information Control, but a few facts are known. A large-scale operation to increase the oxygen content of the planet is under way: skilled workers constantly dump cyanobacteria into the oceans and seed the habitable zone with invasive plant species. Slave labor is largely reserved for the planet's extensive mining industry, which takes advantage of the high-density planet's rich lodes of ferrous and heavy metals. Alliance intelligence has also confirmed that the colony is home to several batarian military installations, a threatening sign for a planet this close to Earth's Local Cluster and the Exodus Relay. Its infrastructure includes many satellites and several space stations.”

Basically, the two paragraphs in the leaked version were condensed in a single paragraph (talking about Jon Grissom and cyanobacteria and invasive plant species) to make room for EDI’s travel advisory (and the final version is still shorter). The final version also erases all references to Aratoht’s proximity to Earth, presumably because they moved Aratoht to the “southern” galactic rim - though they still upheld its status as a Skyllian Verge world. We’ll get to the troubles of the position of the Viper Nebula and its impact on the geography of the Skyllian Verge in due time, but for me the leak only adds to our understanding of the dispute over Aratoht - the political battle lasted a full year, and the Citadel Council’s Committee on Habitable Worlds (referenced elsewhere though the lore) appeared to have been on the side of the Alliance until the Alliance dropped the issue.

** : This one is a bit of a stretch and comes from Kai Leng’s dossier, of all places. In 2173, the entry in the list of his tours of duty reads : “Exodus Cluster Patrol and reconnaissance (reprimanded for taking medals from dead enemy officers; sentence was reduced in light of previous, exemplary service record)”. There’s an interesting tension here : “Patrol and reconnaissance” suggests that this was a very routine assignment (even more so given that Leng had enlisted only one year before) in 100% Alliance territory, the Exodus Cluster. However, it appears that Leng’s unit engaged with a unit from another military, and a hostile one : “dead enemy officers” and “medals” leave little doubt to the fact that the enemy was related to some kind of state. At this point in the history of Mass Effect, the only state hostile to the Alliance that we know of is the Batarian Hegemony, who happens to be right next door, in the Kite’s Nest.

† : This is the event that sparks the ME3 quest “Citadel : Hanar Diplomat”. The justification for the dates I have are that the batarians acquire the Leviathan of Dis in 2163 - and Occam’s Razor leaves me disinclined to believe that the Hegemony had another Reaper gizmo to study. As for 2175, that was the year grayboxes were outlawed, after Alliance Intelligence Agency employee “Abraham Rumoi” was tried for treason, since Rumoi was in fact “[the] professional conman and thief named Keiji Okuda, who accessed and sold classified data”. The Alliance black ops raid was the Big Bad Event stored in Keiji’s graybox that Donovan Hock was after in Kasumi’s DLC - therefore, the raid can’t have taken place after 2175. Personally I’m partial to batarians ratcheting up research into Reaper tech after 2171, but that’s just me.

Having said all of this, let us now consider the places that we know for sure are in the Skyllian Verge, and see what we can make from that.

the Armstrong Nebula, surprisingly, is in the Skyllian Verge, despite its distance from batarian space - https://masseffect.fandom.com/wiki/UNC:_Geth_Incursions ;

so is the Petra Nebula (Elysium) ;

so is the Viper Nebula (Aratoht, despite the sheer distance from batarian space. It’s indisputably in the region, that fact is repeatedly stressed in multiple sources - for example the Codex entry for Aratoht, or this : https://masseffect.fandom.com/wiki/Cerberus_Daily_News_-_January_2011#01.2F22.2F2011_-_Batarian_and_Alliance_Forces_in_Standoff_in_Skyllian_Verge

so is Hades Gamma (see above, on “Lord” Darius).

Since the Skyllian Verge is supposed to be in the buffer zone between Systems Alliance and Batarian Hegemony space, I expected it to be solely hugging the borders of the Batarian Hegemony, in “Earth Systems Alliance Space” (see Post 5c for more details). But from the above we see that the Skyllian Verge is much larger than that and covers a great deal of space, from the Viper Nebula on the galaxy’s edge in what is technically Inner Council Space, to the Petra Nebula or Hades Gamma in “Earth Systems Alliance Space” (read : the Attican Traverse), to the Armstrong Nebula which is in the Attican Traverse even on what I assume is an Alliance map.

Moreover, we have significant information on where the Skyllian Verge ends : Tefnut, in the Nubian Expanse, “is a major gateway to the [Skyllian] Verge and the Terminus Systems”. This leaves me inclined to believe that the Nubian Expanse is only in the Attican Traverse, outside of the Verge but directly linked to it.

Fig. ¿ : The ME1 Galaxy Map. Many clusters explicitly part of the Skyllian Verge - the Armstrong Nebula, Hades Gamma - are shown for the first time in the original Mass Effect. For reference : the Kite’s Nest would be left of Artemis Tau, while the Petra Nebula would be below the Exodus Cluster. As we’ve seen in Post 5c, the Petra Nebula and Artemis Tau would technically be in what I’m 99% sure is batarian space, centered on the Kite’s Nest.

The Viper Nebula would be at the very end of the spiral arm where Artemis Tau is, below the Local Cluster. The Nubian Expanse would be between the Armstrong Nebula and Sentry Omega.

Very interestingly, each of those clusters poses unique challenges and complications. Let’s go from the most obvious to the least obvious :

Hades Gamma, let alone the Armstrong Nebula, are very far from the Kite’s Nest and batarian space, to the point that the notion that either would be a cluster close enough to batarian space to be considered a zone of privileged expansion, let alone pose a significant security risk to the Hegemony if they were settled by the Alliance, sounds absolutely ludicrous. In ME3, Hades Gamma doesn’t connect to the Kite’s Nest directly, meaning that the fastest route between the two is always through the Exodus Cluster - and the Armstrong Nebula can only be accessed from batarian space through Hades Gamma.

The Nubian Expanse, likewise, is very far from batarian space. It’s worth noting however that batarians attempted to colonize Pragia, in the Nubian Expanse’s gateway system, at some point in the 20th century.

The Viper Nebula is the only cluster in the Mass Effect franchise - alongside Earth’s Local Cluster - to be accessible through a secondary relay. That means somewhere in a sphere of “a few hundred light-years” centered on the Bahak system is another system, unknown and unnamed, with a secondary relay of its own and at least one primary relay connecting it to the larger galaxy. That system would be the gateway system of an unknown, unnamed cluster, but on a map of the galaxy it would be almost exactly where the Viper Nebula is. So we don’t know how that [Unknown Cluster] connects to the larger network, and to what clusters it connects to, but we do know that, regardless of the sheer distance, it’s still considered a part of the Skyllian Verge.

The Petra Nebula, with Elysium, is perhaps the cluster most associated to the Skyllian Verge, but in ME3 it is only connected to the Kite’s Nest through the Exodus Cluster, exactly like Hades Gamma.

Hades Gamma and the Petra Nebula’s exclusive connection to the Kite’s Nest through the Exodus Cluster leads us back to the biggest "lore hole” in Mass Effect, the fact that the Exodus Cluster must have been inaccessible to the batarians by 2149 CE (if it was accessible before).

So what we have is one solid conclusion - the Skyllian Verge appears to include distant clusters that branch out of clusters actually on the batarian borders - but also a list of new questions :

if Hades Gamma and the Petra Nebula could be considered a part of the Skyllian Verge, which is a zone that already existed before anyone made first contact with humanity in 2157 CE, then that means they could be accessed from batarian space, though neither cluster connects to the Kite’s Nest directly - would that be a lore-breaking contradiction, or is it actually possible to squeeze in a hypothesis ?

to what cluster(s) does the [Unknown Cluster], the only link to the Viper Nebula, connect to ?

what other clusters could be a part of the Skyllian Verge ? What clusters are ineligible ?

having answered all of this, can we start defining the Skyllian Verge ?

Alright ! At this point I will only have hypotheses - everything I will say beyond this point is 100% conjecture.

1 : How might Hades Gamma and the Petra Nebula link to the Kite’s Nest, even though they aren’t connected to it on the ME3 Galaxy Map ?

Starting with Hades Gamma, I think it could be possible that the link to the Kite’s Nest might be through Artemis Tau. Artemis Tau is a) canonically connected to Hades Gamma, b) absent from ME3 so we do not know how it connects to the Kite’s Nest, c) in (presumed) batarian space on the Galaxy at War map. Therefore, I’m inclined to believe that Artemis Tau could connect to the Kite’s Nest, either directly or through another cluster, or even several different clusters. However, in keeping with my observations in Post 4 that the connections shown on the ME3 Galaxy Map are always approximations, to make that headcanon fit one of the conditions is that it must take less time to reach Hades Gamma from the Kite’s Nest through the Exodus Cluster than through Artemis Tau - so I were to take up that headcanon I’d squeeze at least one additional cluster between Artemis Tau and the Kite’s Nest.

As for the Petra Nebula, this might actually allow us to solve another lore hole for the cluster (the whole region is riddled with them) : in Elysium’s system, the gateway system of the Petra Nebula, one can read in the description of the planet Joppa that “Human and alien consortiums compete fiercely for the rights to gather helium-3 from the planet, since Elysium's favorable position along trade routes means high profits.” Trade routes ? That makes no sense in the context of the ME3 Galaxy Map, where the Petra Nebula doesn’t connect to any cluster except the Exodus Cluster. We can infer that the Petra Nebula presumably has at least one “branch” of related clusters in the Skyllian Verge that we do not see, but would that be enough to justify such a frenzy of competition ? The only other example that comes to my mind are the He-3 Cartels on Hito, which provide helium-3 to Illium. Would a relative backwater like Elysium be able to draw a 50% non-human population, out of a population of several millions, only five years after its founding ? Simply put, there’s something attractive about Elysium that literally no other Alliance colony appears to have.

However, if we assume that Elysium connects to the Exodus Cluster and the core of Alliance space (canon), additional clusters of the Skyllian Verge (likely, but unverified), but also to batarian space through hypothetical clusters (100% conjecture) and also to the Citadel (100% conjecture) because the batarians need a route to the Citadel if the Exodus Cluster is inaccessible, then we make a crossroads out of the Petra Nebula, one that could explain this unprecedented attractive factor to non-human immigration and investment, especially in a notoriously unstable region like the Skyllian Verge.

But let me put a wrench in my own hypothesis : if the batarians could access the Petra Nebula before the humans could, a cluster so well-located and with a garden world in the middle… why didn’t they colonize it before the humans ? You could invent several explanations for that - my personal favorite at the moment is that economic sanctions imposed on the Batarian Hegemony, probably incurred after their (canon) battles/wars with the salarians in c.1785 and “Citadel forces” in c.2115, left them economically unable to expand to the Petra Nebula (and all the more if there were political considerations as well). But it’s just one possible headcanon ! In the end, it’s all up to you.

2 : Where does the [Unknown Cluster] connect to the larger mass relay network ?

In ME2′s Galaxy Map, the Viper Nebula only links to Earth’s Local Cluster, at a time where the Alpha Relay is “only” behaving as a secondary relay. The problem with that is that it’s… difficult to consider that a proof of any kind : as I’ve shown in Post 4, the ME2 map is a mess made without much forethought, to the point that the ME3 map retcons most of it where it can. Moreover, in ME2 the Local Cluster is just about the only cluster in the lower third of the galaxy map (the other is the Krogan DMZ), literally the closest available cluster among those depicted in the game. Therefore, I think it’s quite reasonable to assume that connection is (say it with me now) an approximation of a more complex, distributed chain of mass relay connections.

We know that Aratoht is part of the Skyllian Verge but not close to batarian space, which means the [Unknown Cluster] is probably connected to at least one Skyllian Verge cluster leading into batarian space ; we also know that Aratoht is “too close to human space for the Alliance’s comfort”, which means there aren’t that many relay jumps between Aratoht and an Alliance-held cluster. This leaves me inclined to believe that the connection to human space from the Viper Nebula would eventually end up to that “branch” off the Petra Nebula I just blabbered about, or to those clusters branching off the Arcturus Stream at Relay 202, “contested space” with “an unsavory reputation”.

Beyond that, I don’t have much !

3 : What canon clusters are eligible as parts of the Skyllian Verge ?

I made a map again !

Fig ¿? : Canon clusters (and the [Unknown Cluster]) and their relationship to the Skyllian Verge. I didn’t include the other “branch” of the ME1 Galaxy Map, the branch stemming from the Horse Head Nebula, because the only ME1 clusters which canonically are part of the Skyllian Verge are on the Hades Gamma branch. Moreover, if we keep in mind the lore hole of the Exodus Cluster, the Horse Head Nebula branch would be even further from batarian space that it is now, since the quickest way we know (in canon) to access it (assuming an indirect connection with Hades Gamma) would be through Hades Gamma, then Attican Beta, Kepler Verge, Shadow Sea, and then you can go to Argos Rho or Hawking Eta in the HHN branch.

OK, so, a quick overview of the map’s key :

each cross stands for a cluster with at least one mass relay. Each cross is always in a green circle, representing the implicit access to nearby clusters through secondary mass relays.

three parallel black lines represent a connection between clusters through primary mass relays. A single green line (here only between the Viper Nebula and the [Unknown Cluster]) represents a connection through secondary mass relays. Each of the wavy blue lines represents a possible primary relay connection between clusters when two clusters are never present in the same game (e.g. Artemis Tau only appears in ME1, the Kite’s Nest only appears in ME3).

when no line connects two clusters, that means there is evidence of no connection between those clusters in one of the OT games. In order to make the map comprehensible, I have privileged the connections depicted in ME3 over those in ME2 (e.g. in ME2, the Nubian Expanse and the Shadow Sea are directly connected, but as that is no longer the case in ME3, I choose to acknowledge the retcon). EDIT : I could/should have drawn a wavy blue line between Artemis Tau (ME1) and the Petra Nebula (ME3), but also between the Maroon Sea (ME1) and the Nubian Expanse (ME2, ME3).

More relevantly to our present concerns, in canon :

cluster names underlined in purple are canonically in the Skyllian Verge : the Armstrong Nebula, Hades Gamma, the Petra Nebula, the Viper Nebula.

cluster names underlined in orange are canonically not in the Skyllian Verge : the Nubian Expanse, the Kite’s Nest, the Exodus Cluster.

Then, regarding my own hypotheses :

cluster names underlined in blue are so overwhelmingly likely to be part of the Skyllian Verge that I cannot think of a single reason why they wouldn’t be in it - the [Unknown Cluster] because it’s the only link between the Viper Nebula and the wider galaxy, Attican Beta because it’s the only link between the canonically Skyllian Hades Gamma and the equally canonically Skyllian Armstrong Nebula. However, there is no canon confirmation.

cluster names underlined in green, I find these likely to be in the Skyllian Verge.

cluster names underlined in yellow, I find these unlikely to be in the Skyllian Verge.

Now, regarding those last two categories and my choices :

Artemis Tau, Gemini Sigma, and the Voyager Cluster : Since I’m completely certain Attican Beta, stemming from Hades Gamma, must be part of the Skyllian Verge, and since the Armstrong Nebula, much farther from batarian space than any of those three clusters, is canonically part of the Skyllian Verge, then any cluster branching off Hades Gamma is good in my book.

But what about those clusters which branch off Attican Beta ? Why is the Armstrong Nebula officially part of the Verge and the Nubian Expanse officially not ?

The only key difference I can surmise between the two is that the Nubian Expanse is an entry point into the Terminus Systems (see above) while the Armstrong Nebula isn’t.

Since Sentry Omega is at the far end of the Attican Traverse but also so damn close to the Terminus Systems (which you cannot see on any map), I think it’s likely to be in the same position as the Nubian Expanse, between the Skyllian Verge and the Terminus Systems.

The Maroon Sea is a cluster with no evidence of a direct connection to the Terminus System. Furthermore, on the Galaxy At War map, it falls in ESASpace. While the Armstrong Nebula, a canonically Skyllian cluster, is not in ESASpace, for some reason, the fact the Maroon Sea entails that, at the very least, the Alliance considers it more a part of its territory/an area where it can project its military strength more easily than, for example, Sentry Omega. Hence I chose to make it a Skyllian cluster.

The Shadow Sea (Horizon’s cluster) is actually outside of either of the two big “branches” of the ME1 Galaxy map, though it bridges them : it’s connected to the Kepler Verge in the HG branch and to Argos Rho and Hawking Eta in the HHN branch. Moreover, given that, like the Nubian Expanse, it is connected to the larger Terminus Systems through the Caleston Rift (not shown on the map), I think all of those factors combined make it unlikely to be part of the Skyllian Verge.

And then there’s the Kepler Verge. Its only connection to the Terminus Systems is through the Nubian Expanse and the Shadow Sea, to which it is connected. Moreover, as we’ve seen, “verge” means edge, border - so I tend to believe that the Kepler Verge is the verge of the Skyllian Verge, of human space, one relay jump from one of the nearby gateways into the Terminus Systems.

There ! Those were my thoughts !

4 : So what is the Skyllian Verge ?

Based on everything I’ve said, I think the Skyllian Verge, originally defined as the part of the Attican Traverse close to batarian space where the Batarian Hegemony intended to expand next, is a region that encompasses both the clusters which are close to the borders of the Batarian Hegemony, assumed to be that quasi-rectangular block at the bottom of “Earth Systems Alliance Space”, and the “branches” of relay connections stemming from those clusters. If the Nubian Expanse is any indication, the Skyllian Verge would stop when those relay connections would lead into territory that was either unsafe (in the case of the Nubian Expanse, go too far “north” and you’re in the Terminus Systems) or already claimed (presumably go too far “west” and you’re in turian space).

And that’s it !

So ends the fifth part of my five-part fifth post in the G2HGE series. I hope you found this post as interesting to read as I found it to research and write. See you next time !

(For the schedule as it stands, please refer to Post 5a.)

G2HGE Index :

Post 0 : Presentation and Purpose

Post 1 : Methodology and general lamentation over the incoherent state of the lore.

Post 2a : Oldest canon date for activity in every single cluster

Post 2b : Organization and Visualization of the above

Post 3 : The oversized impact of the asari, and a surprising amount of stuff to discover.

Post 4 : The Problem with the Galaxy Maps

Post 5a : The Regions of the Milky Way : Overview and Council Space

Post 5b : The Regions of the Milky Way : The Terminus Systems

Post 5c : The Regions of the Milky Way : The Attican Traverse and Earth Systems Alliance Space

Post 5d : The Regions of the Milky Way : The Nemean Abyss and the Perseus Veil

3 - What is the Perseus Veil ? Where is the Nemean Abyss ?

Fig. 1 : Where is the Nemean Abyss ? Not on this map.

First, a caveat : in Post 5a, I said this part of the overall post - Post 5d - would focus on the Nemean Abyss and the Perseus Veil as regions of space that are not depicted. That was a blunder, too late to edit : the Perseus Veil is consistently talked about as a natural astronomical structure - a nebula - completely obscuring geth space from outside observers, be they in the Terminus or in Council space ; the cluster also named the Perseus Veil, where Rannoch is, is either in the nebula itself or close enough to be identified to it (if the nebula is so opaque, could starships actually fly between the stars in that nebula ?).

My confusion stemmed from the fact that in the IRL Milky Way, the Far Rim - Haestrom’s cluster, from which one can access the Perseus Veil cluster - would be on the outer edge of a spiral arm called the Sagittarius Arm, while the Perseus Veil is shown on the ME3 Galaxy Map to be a) not on this spiral arm, and b) straddling the border of the Terminus Systems region, halfway in that big gap at about 2 o’clock on the map between the Terminus Systems and the Attican Traverse.

It’s not a completely empty gap ; on the ME3 Galaxy Map, the edge of the Sagittarius Arm protrudes slightly into that space, as does the tip of the spiral arm coming after the Sagittarius Arm - the Perseus Arm.

My WIP hypothesis was, since I mistook the Perseus Veil for a region, that the Veil was called “Perseus” because it actually was attached to the Perseus Arm, but that is entirely incorrect. At the moment, if I were to guess, I’d say the Perseus Veil nebula was so named because while it is a structure in the Sagittarius Arm it obscures the fraying tip of the Perseus Arm from whoever wants to spy on the geth. That gap on the map I talked about would be geth space, just as inaccessible as the Galactic Core, and the Perseus Veil cluster is the entry point into that space. That is entirely in the realm of speculation however, so let’s focus on something more tangible.

The Nemean Abyss, on the other hand, is always described as a region. Basically, the Nemean Abyss is the region of space where most of Jacob’s adventure in the mobile game Mass Effect Galaxy, a prequel to ME2 and referenced in parts during ME2′s storyline, takes place. To keep it brief, the Nemean Abyss is basically the Terminus Systems, but Worse.

The Nemean Abyss is described as “farther out” than the Terminus Systems, and also as “the darkest part of the galaxy … Even the Council races don’t often go out there.” It’s All Crime All The Time. Here are the locations in the Abyss we know. Cartagena Station is the entry point into the Nemean Abyss from Main Games space. It serves as a discount Citadel. The planet Tortuga is the discount Omega of the region (Omega of course building off Star Wars’ Mos Eisley, itself a scifi elaboration on the original Tortuga, taking us full circle). Bekke appears to be a Hegemony colony or concern where the batarians mine eezo. Finally, the Ahn’Kedar Orbital Platform (no relation to the human corporation Hahne-Kedar, presumably) is a batarian research station. Overall, the Batarian Hegemony or related batarian groups appear overwhelmingly present in the Nemean Abyss. However, at some point in MEG Miranda (I believe) refers to a part of the Abyss as “the Batarian Fringe”, which would indicate that while the batarians are one of the heavyweights of the Abyss as a whole, they’re not the only ones (otherwise why would the unique characteristic of that Fringe be that it’s “Batarian” ?).

Fig. 2 : The Mass Effect Galaxy galaxy map. While this is obviously a map which would contract the galaxy maps of ME2 or ME3 should it be compared to either, it can yield interesting information as to the Nemean Abyss’s intended location.

Interestingly, the Citadel’s position as well as the shape of the spiral arms allow us to see that the Nemean Abyss is meant to be to its “northeast”, “west” and “northwest” of the Galactic Core. As it happens, there is a lot of unoccupied space in that part of the Attican Traverse close to the Core, the so-called (by me) “little” Traverse. One could very easily fit an independent region there.

Of course, it could absolutely be possible that the Nemean Abyss is where it is shown to be, only it is a “branch” distinct and separate from the rest of the relay network. From a “bird’s eye” (Reaper’s eye ?) view of the galaxy, the Nemean Abyss would be in the middle of the map of clusters we know from ME2 and ME3, but only remotely connected to them. Mapping on a 2D surface would collapse the distance of a 3D volume like a galaxy, but lest we forget, the disk of the Milky Way is about 1,000 light-years thick ! There’s room !

Note, however, that the fact the Nemean Abyss is described as “farther” than the Terminus Systems logically entails that the Nemean Abyss can only be accessed through the Terminus Systems - in which case, the map above can be entirely discounted, depending on your preference.

The Nemean Abyss is noted as being as rich in eezo as a whole. This has budded into a bit of local folklore - “This has led to wild stories that there are actually drifting starships in the Abyss made of element zero. While these are likely exaggerated, there are certainly cases of ships being captured by pirates while carrying huge eezo shipments.” - but it’s also interesting because, wherever we headcanon the Nemean Abyss to actually be, there needs to be a reason for all that abnormally widespread eezo abundance. Since eezo is created “when solid matter, such as a planet, is affected by the energy of a star going supernova. The material is common in the asteroid debris that orbit neutron stars and pulsars.”, that means there must be or have been more supernovae in the Nemean Abyss than the galactic average, therefore a higher proportion of older, now dead, stars. I do not know enough about stars (yet !) to say for sure where that would be likelier to happen.

So if you want to include the Nemean Abyss somehow, you’ve got plenty of possibilities.

Besides references to Jacob’s past adventures, ME2 also contains explicit or implicit references to the Nemean Abyss. On Omega, the player can overhear the following advertisement :

“The Nemean Abyss yawns wide. Will you be the one to fill it ? Dah'Tan Manufacturing has opened offices all over the Sin'Kelar Cluster and beyond, preparing to drive civilization into the unconquered reaches of the Abyss ! Only the bravest, most qualified, and most dedicated people will survive in the harsh reaches of the most untamed sector of the galaxy. If you're that type of person, apply to Dah'Tan Manufacturing today... and look into the Abyss !“

So we have one more bit of geographical lore here : the Sin’Kelar Cluster (never seen in any game or related material) is a cluster very close to the Nemean Abyss, presumably a cluster in the Terminus Systems and not too far from Omega… Moreover, Dah’Tan Manufacturing is a batarian corporation based on the Hegemony world of Camala, suggesting that the expansion and exploitation of the Batarian Hegemony in the Nemean Abyss was still an ongoing process in 2185.

In another ad on Omega, you can hear about the Bekke Burlesque, which appears to regularly tour both the Nemean Abyss and the Terminus Systems, including Afterlife on Omega. Whenever “Bekan Ja'Tash” (batarian name - the manager ?) and his "sexy sextet" perform, it is advertised as the event of the century. ("You won't believe what these girls get up to… and how low they'll go. You won't believe your eyes !")

And that’s it for the Nemean Abyss - now, onto the good stuff.

Tomorrow : the Skyllian Verge ! See you there !

G2HGE Index :

Post 0 : Presentation and Purpose

Post 1 : Methodology and general lamentation over the incoherent state of the lore.

Post 2a : Oldest canon date for activity in every single cluster

Post 2b : Organization and Visualization of the above

Post 3 : The oversized impact of the asari, and a surprising amount of stuff to discover.

Post 4 : The Problem with the Galaxy Maps

Post 5a : The Regions of the Milky Way : Overview and Council Space

Post 5b : The Regions of the Milky Way : The Terminus Systems

Post 5c : The Regions of the Milky Way : The Attican Traverse and Earth Systems Alliance Space

2.3 : The Attican Traverse and Earth Systems Alliance Space, so-called

Like I said beforehand, the Attican Traverse’s defining political characteristic is that it’s officially claimed by the Citadel but contested in places by the Terminus Systems. “Unwilling to engage in an all-out war against the Terminus Systems, the Citadel has adopted a military non-interference policy in the region.”

Geographically, the Attican Traverse is a buffer zone between Council Space and the Terminus Systems. On the Galaxy at War map, the region is the only one to span the diameter of the galaxy, extending from its “westernmost” point to the “easternmost” one. In that regard, the name “Traverse” is apt, as “traverse” can designate an element extending across a larger structure, from side to side.

While the Attican Traverse on the map is a single continuous region, it’s worth noting that functionally there would actually be two separate Attican Traverses, thanks to the mass relay network : a “little” Traverse to the “west” of the Galactic Core, i.e. the Ismar Frontier and the Eagle Nebula, connecting Council Space in the “south” to the Terminus Systems in the “north” ; and a “great” Traverse - i.e. the rest of the Attican Traverse, to the “east” and “southeast” of the Galactic Core

With the mass relay network we’ve been given (keeping in mind that we are ignoring if we can the ME2 map), this “little” Traverse does not directly connect to the “great” Traverse at all. The links between the “northwestern” and “northeastern” quarters of the map… basically boil down to the Omega Nebula which actually makes sense given that the Nebula’s gateway system hosts the Collectors’ access point to the whole galaxy. This means that the people who live in the Ismar Frontier or the Eagle Nebula are likely to be more influenced by what’s going on on the Citadel, Illium or Omega than by parts of the “great” Traverse, which are much farther, even though they are all technically in the same region.

This is the most succinct description of the Attican Traverse as a region : “Located near the lawless Terminus Systems, the Attican Traverse is the true frontier of Citadel-controlled space. The area contains many worlds once inhabited by the Protheans, and many mass relays are located throughout the systems of the Traverse. Colonies established in the Traverse are subject to constant raids and attacks from the nearby Terminus Systems, but the presence of multiple worlds both rich in resources and Prothean ruins, continues to draw colonizing interest.”

So that’s it, right ? Wrong. There’s more. The problem with the Attican Traverse and Earth Systems Alliance Space is that basically everyone outside of the Alliance appears to treat ESASpace as part of the Attican Traverse : in ME1 for example, the volus merchant Expat describes Noveria as “the corporate capital of the Attican Traverse”. This, alongside other elements*, suggests that in ME1 the parts of the galaxy the player can explore - divided, in ME3 terms, between ESASpace and the “great” Traverse - were all considered parts of the Attican Traverse at the time. “Earth Systems Alliance Space” isn’t older than ME3.

* : ME1 Codex entry “Uncharted Worlds” : “Humanity’s early expansion into the Attican Traverse was haphazard; a desperate race to claim habitable planets where populations can be economically settled. Ignored in the wake of this land grab were thousands of less hospitable worlds, each potentially rich with industrial resources. The wealth of entire solar systems lies untapped, waiting for corporate survey teams or independent pioneers to discover and exploit them. This, however, is not an easy task. In addition to the environmental hazards, the fact that uncharted worlds are largely ignored makes them popular bases for criminals, revolutionaries, cults, and others who wish to remain unnoticed by galactic society.”

Description in the Journal of the ME1 assignment “UNC: Valuable Minerals” : “To maintain its fleets and continue to expand, the Alliance must find new resources wherever it can. You've recently surveyed an important deposit and claimed it for the Alliance. There must be more like them in the Traverse.” The worlds with valuable minerals are all over the ME1 galaxy map.

Lastly, the regular comments in ME1 that Eden Prime and the Exodus Cluster are in the Attican Traverse make a lot more sense in that regard. In practice, they are. (The comments that the Terminus Systems are close, mentioned in Post 5b, still don’t make sense.)

So what even is Earth Systems Alliance Space ?

Doylistically, I’m pretty sure it’s whoever designed the ME3 galactic regions map deciding, for gameplay reasons, that the Attican Traverse was too large and needed to be split notwithstanding the fact that this would put the Batarian Hegemony in space claimed by the Alliance. In the simplest terms, Earth Systems Alliance Space is an ME3 invention, papering over parts of what had been, up to that point, the Attican Traverse.

In Watsonian terms, it’s probably the equivalent of such or such IRL political entity making itself feel important by placing itself at the center of the world, sometimes literally*. Given that the Alliance has spent most of its existence trying to prove it’s the equal of the other Citadel races, a self-aggrandizing geographical trick sounds perfectly in character. It’s the Alliance showing this map of the galaxy to its fellow Council members and saying, “We are a big deal ! We are just as big as all of you combined !” and the non-humans in the room saying, “…your worlds are part of Citadel Space. Why did you represent yourself outside of Council Space ?”

* : The only reason Europe is at the center of the standard world maps today is because of the lasting impact of colonialism, and the supremacy of European empires in the recent past ; it’s no less an arbitrary choice than a world map where the Pacific is shown in full and the Americas are shown to the right of the map, or even an Americas-centered map with Eurasia split in two.

All of that to say that I doubt anyone outside of the Alliance actually thinks of “Earth Systems Alliance Space” as something other than wishful thinking on the Alliance’s part, and that the Attican Traverse, for non-humans, includes that region of space.

Context ? Context.

Those pretensions actually make sense in light of the way the Alliance has always related to the Attican Traverse in the lore. In ME1 and ME3, we are told again and again that “the Council makes no objection to the Systems Alliance's expansion in the Traverse, because the large Alliance Navy can settle unstable regions without the Council needing to get involved.” In other words, the Council can (and did) use the Alliance to actually substantiate its claim to the Traverse. As for the Alliance, we saw in the last Codex entry I quoted (“Uncharted Worlds”) that the Alliance’s “early” phase of “aggressive expansionism” into the Traverse focused on the best worlds, and by the time of ME1 the Alliance is edging its bets by exploring more carefully the largely uncharted Traverse, looking for valuable resources.

As we saw in Post 1, one of the biggest plot holes in the lore of Mass Effect is that the Exodus Cluster, colonized by the Alliance as early as 2152 CE, is directly connected to the Kite’s Nest, the Horsehead Nebula and Hades Gamma, which by this point have all been accessible to the various non-human races of the galaxy for some time. The only way for the humans to avoid making first contact with everyone ahead of schedule is if, somehow, for some reason, the Exodus Cluster is completely cut off from the aforementioned clusters (and probably the Petra Nebula as well, because they’d have eagerly jumped on Elysium otherwise) at least until 2157 CE.

This is supported by the colonization dates we have for Alliance colonies : the colonies founded before 2157 are Demeter, Terra Nova and Eden Prime (all established in 2152), Benning (in 2153), Tyr (in 2156) and Shanxi (at some point). The first five colonies in that list are all in the Local Cluster, the Arcturus Stream or the Exodus Cluster ; as I mentioned last time, Shanxi’s system had the Shanxi-Theta mass relay, that led to uncharted space, from the human point of view, which was the periphery of turian space, from the turian point of view. Given that the Turian Empire is in Inner Council Space (see above), this means Shanxi and human expansion were both in that direction, toward the “west”, whereas the Traverse was in the “east”, somehow inaccessible.

Fig. 2 : Personal attempts at representing early Alliance expansion, for the ease of your visualisation. An anomalous astronomical structure, somehow resembling an enormous cat hair, is also depicted drifting between the Kite’s Nest and Hades Gamma clusters. The lore does not attest the existence of such a thing ; it should be disregarded.

With no cluster to expand into past the Exodus Cluster and the Attican Traverse cut off until 2157 at the earliest, the only places left to expand (beside the secondary relay bubbles) are the other two clusters* branching off the Arcturus Stream and the clusters branching off them. In that context, the choice to make Arcturus the center of the Alliance’s administration and eventually government makes a lot of sense, as it was in the geographical center as well. The only things I’ll venture to guess is that Shanxi, and the eventual link to turian space, are somewhere down one of those branches ; and that one of those two mysterious primary relays, Relay 202, “leads into contested space.”

* : for the number of primary mass relays in the Arcturus system, see here.

After the First Contact War of 2157, however, humanity’s expansion possibilities… expanded (sorry). On the basis of the dates we have, the next colonies to be established were Bekenstein (2158), next to the Citadel, and Elysium in 2160. Elysium is the first human colony in the Skyllian Verge (another region difficult to delineate, see below), and that makes it one of the oldest, if not the oldest, Alliance colonies in the Attican Traverse. After that point, most of the Alliance colonies whose settlement dates is known are to be found somewhere in that region*. The sense one has is that, since the Alliance’s expansion to the “west” would inevitably run into Inner Council Space, and since the Alliance was so desperate to play catch-up, then the Alliance did a 180° turn and started focusing its expansion efforts in the actual frontier, the “southeastern” Attican Traverse.

* : Intai’sei (2166), Therum (2167), Ontarom (2170), Feros (2178), Proteus (2179), Gilead (2180), Chasca (2183). Mindoir (settlement date unknown) is also said to be in the Traverse. Since Akuze (2177) is on the “outskirts” of the Alliance, it’s probably in the Traverse as well, but that’s not confirmed. Independent human colonies (e.g. Horizon) are not listed, but there’s also a fair number of them in the Traverse.

If I were to headcanon why the line was drawn where it is on the map to encompass 10 Attican Traverse clusters - the Petra Nebula, the Kite’s Nest, Artemis Tau, Hades Gamma, the Voyager Cluster, Attican Beta, the Maroon Sea, Gemini Sigma, the Horse Head Nebula and Argos Rho - in Earth Systems Alliance Space, I’d probably say ESASpace actually represents the Alliance’s confidence in its ability to project its strength and safeguard its interests, its zone of military influence if you will. But quite frankly, I have no idea why the Maroon Sea is included but not, say, the equally distant Kepler Verge, where the Alliance actually has a colony (Ontarom).

All of this blabbering to say that if the map was made by anyone outside of the Alliance, it probably would look a lot more like this :

Fig. 3 : A flawed reinterpretation, but a likelier one. This isn’t meant to be an actual map, let alone a perfect one. Artemis Tau, which is as much Alliance as a cluster can be this far outside of its Arcturus-centered domain, finds itself… in the Batarian Hegemony in pink (should I headcanon that Artemis Tau connects to batarian space ?), though as previously noted Elysium’s Petra Nebula is also very much inside officially batarian space. Though I guess the Batarian Hegemony after 2171 would technically be part of the Terminus Systems as a “rogue state”, I elected to make it stand out, given that it’s such a particular case.

What really matters on this map is that if you put all of 100% Citadel Space in blue and expand the Attican Traverse in green to encompass what’s called the Traverse in ME1 - i.e. Noveria and all the ME1 systems and clusters - one can see that the Traverse is slightly less than 50% of the surface of the explored galaxy, while Council Space and the Terminus Systems are each slightly over 25% of the map’s area. The size of the actual, bona fide Alliance territory also stands out.

Final note : I have no idea how Attican Beta and the Attican Traverse are related, other than Attican Beta being in the Attican Traverse - but why Attican Beta out of every other cluster in the Traverse ? Where is Attican Alpha ? Where is Attican Gamma ? Why did the Alliance have this craze with Greek letters ? And why are some of the ME1 clusters (Maroon Sea, Kepler Verge, Armstrong Nebula, Voyager Cluster) bereft of Greek letters ? Whyyy ?

Tomorrow : the Nemean Abyss ! The Perseus Veil ! See you there !

G2HGE Index :

Post 0 : Presentation and Purpose

Post 1 : Methodology and general lamentation over the incoherent state of the lore.

Post 2a : Oldest canon date for activity in every single cluster

Post 2b : Organization and Visualization of the above

Post 3 : The oversized impact of the asari, and a surprising amount of stuff to discover.

Post 4 : The Problem with the Galaxy Maps

Post 5a : The Regions of the Milky Way : Overview and Council Space

Post 5b : The Regions of the Milky Way : The Terminus Systems

2.2 : The Terminus Systems - What ? Where ? How ? When ? Why ?

Ah, the Terminus Systems. It’s a place we simultaneously know a lot and little about. Here’s the full Codex entry :

“The Terminus Systems are located on the far side of the Attican Traverse, beyond the space administered by the Citadel Council or claimed by the human Systems Alliance. It is populated by a loose affiliation of minor species, united only in their refusal to acknowledge the political authority of the Council or adhere to the Citadel Conventions.

“Their independence comes at a price; the Terminus is fraught with conflict. War among the various species is common, as governments and dictators constantly rise and fall. The region is a haven for illegal activities, particularly piracy and the slave trade.

“At least once a year, a fleet from Terminus invades the nearby Attican Traverse. These attacks are typically small raids against poorly-defended colonies. The Council rarely retaliates, as sending patrols into the Terminus Systems could unify the disparate species against their common foe, triggering a long and costly war.”

In ME1, the Terminus Systems are never seen but are regularly alluded to and are nonetheless extremely important. In the peripheral text, we learn that “The STG is a proactive organization, puncturing worrisome trends before they become movements. At any time, a dozen groups are operating covertly within the lawless Terminus Systems, sowing dissent among the various factions. Civilian analysts also note how troublesome "hinge point" individuals in Terminus frequently meet unexpected deaths.” or that the Turian Hierarchy built an enormous interferometric telescope array spanning two clusters “to map the Terminus Systems with great accuracy” specifically.

In the game’s narrative itself, the Terminus Systems are mentioned at the very beginning of ME1 by Nihlus and Anderson, when they say that the last thing the Council wants is to be dragged in a major conflict with the Terminus Systems, with raiders from the Terminus Systems or the Attican Traverse being listed as examples of dangerous people who might covet the Beacon and try to take it in order to expand their ability to do harm against the Council species*. Moreover, the Council denies Shepard’s request to go to Ilos in the late game because they fear - again - that this will trigger a war with the Terminus Systems, and the dispositions of their fleets on the border of Council Space reflects that.

* : Worth noting that Anderson says then that Eden Prime is “right on the border of the Terminus Systems”, which it really isn’t, even in the context of ME1 itself : Sentry Omega is also said to be very close to the border of the Terminus Systems, and it’s almost at the other end of the galaxy. I tend to think of that line as an example of early worldbuilding carrying over into the finished game without somehow getting properly scrubbed off.

In ME2, all of that, as with so much else, changes. While there are independent colonies one can read about in the planet descriptions*, the spotlight is on Omega and Illium, the two hubs in the Terminus, and on the three merc organizations. One doesn’t really get the feeling that we are shown and can read about in ME2 could be a major hassle to the Citadel races**.

* : Of all the planets we read about, Aite comes the closest to fitting the bill as it has dictators and the like. But the feeling one gets is more of a rugged frontier with people leaving away from the Citadel supremacy, usually preyed upon by pirates, slavers or/and corporations.

** : The War on Garvug storyline in Cerberus Daily News is actually a canon example of a war on a Terminus world. Basically, three corporations contract rent-a-fleets to invade a world dominated by krogan and vorcha (40% and 30% of the population respectively). Garvug’s fleet is quickly destroyed, but the real trouble is the fierce guerilla warfare on the ground. This is perfectly fine… but you don’t get a feeling, here or anywhere else, that there is a single world which could field enough starships to be an actual threat to Citadel-aligned navies. The “Terminus [pirate] clans” could be dealt with the Alliance Navy alone when they attacked Elysium in 2176 ; if there are bigger fish to worry about, they’re offscreen, and unmentioned.

Likewise, unlike what the Codex entry described*, the only actual “species” we see native from the Terminus Systems are the vorcha ; in game, especially in ME2 where most of the narrative takes place in the Terminus Systems, the player’s actual experience is of individual from species whose homeworlds are in Council Space purposefully living outside of the Citadel’s jurisdiction.

* : It’s not necessarily a problem since the Codex is often erroneous, and one can even headcanon (as I do) that the human-made Codex is widely known for its poor fact-checking ; but that’s turning a bug into a feature.

I’m going to be frank : I actually prefer the ME2 depiction of the Terminus Systems to the ME1 description, if only because I feel it’s more realistic and complex. In ME1, the Terminus Systems are the Bad Guys, dictators, pirates, slavers. With places like Illium or Korlus, one has the feeling that the relationship of the Terminus Systems with the Citadel is more ambivalent and nuanced, politically hostile but mutually dependent economically, that the Terminus Systems sure aren’t a haven of democracy and peace and do threaten innocent people in Citadel Space, but that parties in Citadel Space are more than happy to profit from the lack of laws and rights in the Terminus Systems - much like what we see IRL. But nonetheless, it’s important we take the time to acknowledge that the worldbuilding of the Terminus Systems changed between ME1 and ME2, and that in turn created a hole in the logic of the geopolitics between Citadel and Terminus set up in ME1 and carried over in its sequels*.

* : Of course, this could be a case again, as with most of the asari, salarian and turian colonies as we’ve seen in Post 3, of the player simply… not being shown all of that stuff. But in the case of the Terminus Systems, after building them up in ME1, it’s a strange choice to not address that expectation.

With that out of the way, let’s look at the Terminus Systems in a Watsonian manner.

It’s said that many Terminus worlds are “rife with farmers growing psychoactive substances, armed gangs, and with genetic engineering that would be illegal in Council space” and “a good place to build a habitat and get lost for a few decades.” Moreover, “The prevalence of batarian criminal gangs has led to the batarian language becoming a "lingua franca" in the Terminus.” I also have written down a bit either Ascension or Retribution where the Terminus Systems are described as containing what the Citadel civilizations do not want close at hand - “high-security prisons, sanitaria for those who fell victims to virulent, incurable plagues” - but I can’t for the life of me find the exact source, so take that last one with a grain of salt.

There’s a bit of a blur as to what worlds are part of the Attican Traverse or the Terminus Systems - especially since the distinction, as we’ll see, is that the Traverse as a whole is officially claimed by the Citadel (but the Council has no ability to really enforce that claim) but some systems are contested, and claimed by various Terminus powers. For an example of that blur, look no further than Korlus, in the gateway system of the Eagle Nebula.

Contrary to what the Wiki states, the Eagle Nebula would fall in the region marked as the Attican Traverse and not in the Terminus region, even though Korlus is officially considered by the Citadel as part of the Terminus Systems - indeed, Korlus “ranks second in murder per capita in the Terminus Systems and first in offworlder murder.”

So Korlus is not in the region marked as the Terminus but is nonetheless part of the Terminus Systems… What gives ? My instinct is that on the map, the “northernmost” region marked as “the Terminus Systems” is not claimed by the Citadel at all, unlike the Attican Traverse - but Korlus itself ? I assume that if the Citadel classifies Korlus as Terminus that’s because it doesn’t want anything to do with it. Korlus, the “garbage scow with a climate”, would be Terminus by default.

This handily allows me to transition to my last important fact about the Terminus Systems : even though the Citadel Council absolutely recognizes the Terminus Systems’ independence… the Citadel still considers it its right to enforce its priorities and some of its most important laws everywhere in the galaxy, even outside of its jurisdiction, even in the Terminus Systems.

It’s something which is never stated outright in the games, but it’s there. If the Citadel considers that you can’t open any primary mass relay without knowing where it leads because that is an existential threat in and of itself… it’s not going to let the sovereignty of other nations stop it from making sure no primary relay, even outside of Citadel Space, is ever activated willy-nilly. To stress, the Citadel Council is an institution who has official enforcers who are literally able to do whatever they want in Citadel Space, outside of the laws. That’s the Spectres, who can murder you and walk away, because a Spectre is legally unable to commit crimes.

And you might be thinking, “Come on @crapeaucrapeau​, opening primary relays might be a casus belli, it might be perceived as a security risk and officially motivate the Citadel into threatening war, but you’re making the Citadel Council more evil that it actually is.”

To which I’ll say : let’s look at something far less dire than a risk of repeating the Rachni Wars. Let’s look at Prothean artifacts.

On March 28, 2185, a triad of corporations - Sonax Industries, Guanghui Solutions, and Binary Helix - backed a coup against the krogan government of the Terminus Systems planet Garvug in exchange for “unfettered access to the planet”. The coup failed, and war erupted on Garvug between the government and the corporations. Victory was finally achieved by the corporations on November 14, 2185. During those seven months and a half of war, the Citadel Council did not intervene at all - despite significant public opposition to the corporations’ actions in Citadel Space - because Garvug was in the Terminus Systems and at least two corporations out of three - Sonax and BH - appeared to be based on the Terminus world of Illium. So far, so good.

On December 6, 2185, reporters from Citadel Space brought to light substantial evidence that Sonax Industries and Guanghui Solutions were “concealing a cache of Prothean technology on Garvug for their own private financial gain.” This immediately drew the attention of the Citadel Council’s Committee on Paleotechnology, “which demanded that the corporations allow their inspection team full access to the Garvug site in question or face reprisals to their offices in Citadel space.”

On December 22…

“Citadel Council investigators have announced formal charges against 14 of 24 board members of Sonax Industries and Guanghui Solutions. The move follows an investigation that confirmed those companies withheld Prothean technology from the galactic community for personal gain and instigated an interplanetary war to that end. The investigation credited unnamed Spectres who secured what they say was "irrefutable evidence" of the corporations' complicity. Included in those indicted is Sonax supreme commander Lira Speight. High Commissioner of Galactic Rights Yrania Asula said, "The acts of these corporations went beyond mere illegality and into crimes against the galactic populace. We invoke the right of the Council to admit evidence garnered by Council representatives to prosecute the parties involved for their misdeeds." … [Emphasis mine]”

On the next day, during a Sonax press conference after a salarian Spectre attempted to murder the supreme commander of the corporate armed forces, “…spokesperson Victor Cohen attempted to assuage reporters, saying the Sonax board was "looking into" complying with the Citadel Council, but added that, "the law clearly states that we are in the Terminus Systems, and their act of aggression goes beyond any legal attempt to solve this matter." [Emphasis mine]”

The very next day, on December 24, Sonax Industries’ parent company had rebranded Sonax as “Kore” and “each board member currently under Council investigation for war crimes will be given a retirement package for services rendered” ; Lira Speight, the supreme commander of the armed forces was also relieved of her position. By December 26, she had fled Garvug and disappeared ; “… Asked if she would likely remain in the Terminus Systems to stay outside the Council's reach, spokesperson Dixali Arborandum replied, "If she wants to stay out of our reach, she'd better find another galaxy."” On the following day, her corpse was identified with a certainty by a coroner on Omega, who concluded that she had died of natural causes (stroke), at 47 years old ; “… Lonar Maerun, one of several Citadel Spectres assigned to bring in the fugitive admiral, says the evidence satisfies him. "She was under considerable stress," he said. "I guess it got to her more than she let on."”

The storyline ends here, with a few echoes in Mass Effect 3 suggesting the corporations agreed to collaborate with the Council. What matters here for this post, beyond the terrifying reach and power of the Citadel Council, is the confrontation of two irreconcilable legal principles.

First, there’s Sonax’s, which would be familiar to us, stating that Council laws do not apply outside of Council jurisdiction, much like Australian law does not apply in Libya, for a random IRL example.

The Council’s argument, meanwhile, has this particular turn of phrase : “crimes against the galactic populace”. It sounds a lot like our own “crimes against humanity”, but not entirely, and I’d argue they’re not synonymous. Crimes against humanity are (roughly) defined as a large-scale, systemic campaign of violence severely breaching human rights, committed on purpose by the guilty party in order to further a specific goal (differing from war crimes in that war crimes are isolated and the responsibility of particular individuals) ; what matters is the scale of the atrocities, and their driving intent.

In the case of the Corporate War on Garvug, what the corporations were doing was well-known before December 2185, so it’s not like the Council discovered that the scale of what was being done and realized it had gone past a certain threshold. Likewise, the documented strategy and tactics of the corporations did not qualify as “crimes against the galactic populace” until December. The central, crucial crime is that “those companies withheld Prothean technology from the galactic community for personal gain”.

What I’m getting at is that it really sounds, to me, that the Citadel Council has legally allocated itself the right to step in anywhere in the galaxy if it considers that the galactic community/galactic populace as a whole is in grave danger. The enormous problem with that, beyond the obvious infringement of state sovereignty that represents, is that the Citadel Council and/or its delegate bodies are the sole arbiters of what constitutes a “crime against the galactic populace”.

To belabor an obvious point, the Citadel Council will absolutely consider that polities that are fully recognized as independent and sovereign, i.e. polities that no one in the galaxy assumes that the Council is representing, should nonetheless conform to some of its laws and expectations.

Or else.

In that light, it’s not difficult to understand the core principles defining the Terminus Systems as a political entity. This, and the Codex stating that one of the defining traits of the Terminus Systems is their refusal to “adhere to the Citadel Conventions”, is an important clue as to when the Terminus Systems came into being.

As I stated in Post 3, back in the 4th century CE everyone appeared to agree that the Citadel Council was absolutely in its right to decide who should or shouldn’t get planets currently in the geographical Terminus Systems, be they Talis Fia or Garvug itself - that alone suggests that the Terminus Systems weren’t a thing back then. The Citadel Conventions, meanwhile, “occurred in the wake of the Krogan Rebellions”, i.e. in the 9th century CE. If I were to guess, I’d argue the Terminus Systems were founded in that century at the earliest. But why then ? What’s so bad about the Space!Geneva Conventions ?

Since the Terminus Systems exist in opposition and in reaction to the Council, one of the things to keep in mind is that the Council changed a lot between 580 BCE and 2186 CE. The Council is not, and never was, comprised of the leaders of their species* ; the Councilors cannot order the Turian Hierarchy or the Asari Republics or the Salarian Union or any associate race to do anything like coming together to fight the Reapers unless they are in breach of laws every Citadel race voluntarily agreed to uphold. The Council is meant to arbitrate between its member species, it’s a Supreme Court really… Until you consider the Spectres.

* : In 2186, these were : Primarch Victus (de facto) for the Turian Hierarchy, though normally it would have been the council of all primarchs ; Dalatrass Linron for the Salarian Union ; and no one for the Asari Republics, which is a direct democracy.

The Spectres answer only to the Council and can literally do anything they want in Citadel Space - and get away with a lot elsewhere as we saw with Garvug. That means the Council can legally do what it wants in Citadel Space. I’m sure it’s a power they’re careful not to abuse, to make it palatable - otherwise a lot of races would have left by the 22nd century - but it’s an abusive power in and of itself. And the Spectres were founded in 693 CE, in preparation for the Krogan Rebellions, only to be revealed to the public after that conflict had ended. All of that to say that the Council’s power, authority and importance before and after the Krogan Rebellions are like night and day.

The Council after 800 CE was a very different beast. If I were to guess, the Terminus Systems must have formed in reaction to what the Council had become.

tl;dr : the Terminus Systems :

what ? : both a part of the galaxy that is unclaimed by the Citadel Council (unlike the Attican Traverse) and by default any polity that is not considered part of Citadel Space by both the polity and the Citadel itself - characterized by a refusal to recognize any legitimacy to the Council’s power.

where ? : the “northernmost” third of the galaxy, mostly, though it’s dotted with Citadel-aligned planets and systems.

how ? : mostly, it would be too much of a hassle for the Citadel to expand where there would be anything worth expanding in, and parties in Citadel Space profit from the freedom from the Citadel laws.

when ? : in all likelihood after the Krogan Rebellions.

why ? : the Council after the Rebellions is absolutely terrifying.

Tomorrow : the Attican Traverse and Earth Systems Alliance Space ! See you there !

G2HGE Index :

Post 0 : Presentation and Purpose

Post 1 : Methodology and general lamentation over the incoherent state of the lore.

Post 2a : Oldest canon date for activity in every single cluster

Post 2b : Organization and Visualization of the above

Post 3 : The oversized impact of the asari, and a surprising amount of stuff to discover.

Post 4 : The Problem with the Galaxy Maps

Post 5a : The Regions of the Milky Way : Overview and Council Space