Spectre Induction
Mass Effect is set in the year 2183 with humanity being the newest kid in the galactic block, populated by the species that make up the Citadel Council — a two-and-a-half-thousand years old institution that is, for better or worse, basically Space UN. It is headquartered in a huge, O'Neill Cylinderesque station called the Citadel (gasp!) which predates all current spacefaring civilisations, all of which inevitably end up stumbling upon it sooner or later, as travel across the galaxy happens via use of Mass Relays — constructs which superluminally catapult starships to another receiving Relay, usually (but not always) forming pairs — and all Mass Relays lead to the Citadel.
The construction of the Citadel and Relay network alike are ascribed to an extinct spacefaring civilisation which seems to have at one point ranged most of the galaxy: the Protheans (why, what an original name for a precursor species! But I digress). In truth, the reality is not so simple and clear-cut, but if you haven't played the games I shan't spoil it for you.
Beyond the Relays, faster-than-light travel is also accomplished via use of the eponymous mass effect, a phenomenon which allows for the manipulation of apparent masses via Dark Energy Shenanigans™. Ships travelling under their own power, however, accumulate a static charge over time that, unless discharged at a suitable magnetosphere somewhere, will eventually vacuum arc and fry, kill, and toast (in more-or-less that order) any living thing and computer aboard the vessel. It is also notoriously slower than Relay travel; while no straightforward figure is given in the games themselves, from dialogue we can safely assume speeds on the order of ~10 Light-years/day.
As a natural consequence, space in Mass Effect ends up getting divided into clusters — star systems located around Mass Relays that can easily be reached from said Relay under a starship's own FTL motive power, which is how you navigate space in the games (most notably 2 and 3, where you actually get to fly a little SSV Normandy across the map instead of just selecting worlds). Instead of being correlated by physical proximity then, what truly matters is how the worlds are connected to one another via their associated Relays, forming what is essentially a node graph. Mathematicians in the crowd, rejoice.
The Secret Labs
Much like we do in Mass Effect('s opening cutscene), the best place to start this endeavour is in the Sol system. The reason for that is simple: we know what the real Solar System is like, and therefore have something to compare the information given in the system map to. Take, for instance, the entry for Earth:
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| Home sweet home... |
This follows a very standard pattern for the entries of terrestrial worlds: the Description common to all non-stellar bodies and then social data for specific inhabited worlds, followed by orbital distance (more often than not omitted), orbital period, radius, day length, atmospheric pressure, surface temperature and curiously omitted in this case, surface gravity.
From this we can already gather some interesting information about how Mass Effect presents its planetary data: from the Radius entry, we learn that it is specifying the equatorial radius of the given body. Earth is not a perfect sphere, but rather an oblate spheroid, due to the centrifugal forces* caused by its rotation around its own axis. The result is that its polar radius is ~6356.752 km, its mean radius is ~6371 km, and its equatorial radius is ~6378.137 km, which matches closest to that presented in the entry.
* Inertial forces are still mathematically forces, grow up.
Similarly, we can see from the Day Length entry that it is referring to its Sidereal day, not its Solar day — a little known fact is that Earth does not take 24 hours to rotate around its own axis. No, that 24 hours period is how long it takes for the sun to reach its highest position in the sky between two different days; this is called the 'Solar Day', for obvious reasons. The Earth's rotation period is instead, 23 hours, 56 minutes and 4.1(-ish)† seconds (which comes out to ~23.9344 hours). The reason for this discrepancy is that, while the Earth is merrily spinning around itself, it is also rotating around the sun at a rate of roughly 0.985° every day, such that if you waited exactly 24 hours, the sun would not be in the same place in the sky as the moment you began counting. The Wikipedia page for Sidereal Period has illustrated explanations which might make this easier to follow, but the long and short of it is, the Day Length entries seem to indicate the planet's rotation period.
† This small variability is why leap seconds are a thing.
The last figure of particular interest is Surface Temperature. Mass Effect gives this as 23°C, but Earth's average surface temperature in real life is 15°C. The game is set in the year 2183 and global warming could have changed that figure, but with a warming of 8°C!? If that were the case, the ensuing ecological collapse would be noted somewhere. A more reasonable explanation is that instead of the Global Surface Temperature, the game is giving the average yearly temperature at the planet's tropics. The city of Campinas, for example, located 60 km from the Tropic of Capricorn, has an yearly average temperature of 22.4°C. Factor in a bit of global warming, and we have a potential match.
While finding a plausible explanation for the value is rewarding, I find the implications of it rather unsatisfactory — if we wish to use Surface Temperature to try and calculate other parameters, this tropics-reliant definition makes it so we need to know the planet's Axial Tilt to arrive at any meaningful figures, which is not a value Mass Effect gives us. This relegates 'Surface Temperature' entries to merely qualitative comparisons when assessing planets, instead of an useful property.
Alright then, we have an initial set of assumptions. How well do they hold in practice? Let us test them by having a look at Earth's little brother, good ol' Mars:
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| I actually have very strong feelings against Mars, but that's probably best saved for another post... |
The listed Radius is 3402 km, which is actually a bit larger than Mars' actual equatorial radius of 3396.2 km, but given the mean and polar radii are both smaller than it, sure, let's go with that. The listed Orbital Period is 1.88 Earth Years, which matches almost exactly with the real one. Day Length is given as 24.6 hours, which is closer to Mars' Sidereal Day (24.62297 hours) than its Solar Day (24.66 hours), so again our assumption here holds. The Surface Temperature is listed as -138°C, which once again presents problems. According to wikipedia:
“Surface temperatures may reach a high of about 20 °C (293 K; 68 °F) at noon, at the equator, and a low of about −153 °C (120 K; −243 °F) at the poles.”
So it at least seems plausible that the median temperature at the tropics (which on Mars are at latitudes 25.19°N and 25.19°S) could be around -138°C, but I lack the data to confirm that.
Lastly, it gives us the Surface Gravity value as 0.38 G. Mars' surface gravity is 3.72 m/s², so checking the given Mass Effect value against it confirms that they're (probably) using the usual 9.81 m/s² for their definition of G.
And with that, we have a good grasp on what, exactly, these entries are telling us and therefore what we can and can't do with them! And just for completion's sake, here's Jupiter as a stand-in for the usual Gas Giant entry:
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| [Gustav Holst intensifies] |
The Gas Giant entries lack a lot of the Terrestrials' data values for, well... self-evident reasons. As with those, most omit the Orbital Distance entry. The Radius given for Jupiter here is 71492 km, which matches that found by the 1 atm convention exactly — as Gas Giants don't really have a 'surface' per see, the adopted convention is to consider the altitude at which their atmospheres reach the same pressure as Earth's at its surface (1 atm) to be the Gas Giant's 'surface'.
Now that we have our bearings, we're ready to set out for the wider galaxy. Let us see what the universe is like beyond the Charon mass relay.
Uncharted Worlds
Anyhow, Mass Effect features 17 individual clusters — these are:
- Argos Rho — 3 Systems
- Armstrong Nebula — 5 Systems
- Artemis Tau — 4 Systems
- Attican Beta — 2 Systems
- Exodus Cluster — 2 Systems
- Gemini Sigma — 2 Systems
- Hades Gamma — 5 Systems
- Hawking Eta — 1 System
- Horse Head Nebula — 3 Systems
- Kepler Verge — 2 Systems
- Local Cluster — 1 System
- Maroon Sea — 3 Systems
- Pangaea Expanse — 1 System
- Sentry Omega — 1 System
- Serpent Nebula — 1 System
- Styx Theta — 2 Systems
- Voyager Cluster — 3 Systems
Totalling 41 individual star systems.
You might recognise one other name beyond Local Cluster — the game features the Horsehead [sic] Nebula (Barnard 33) as one of its clusters. This opens up some interesting venues of investigation when it comes to mapping out the Mass Effect galaxy onto the real Milky Way, but that's something I intend to do in the last post of this series. For now, it's but an interesting observation.
There are many curious things to note about the planet descriptions, but the one that really draws my attention is how often they point out not only the atmosphere's chemical composition, but the surface's as well — this is something I feel is frequently ignored by most science fiction.
Anyhow, my point being: different stars have different metallicities, and even stars of a same metallicity will most likely show differences in their relative abundances of specific chemical elements, with those stars formed in a same stellar nursery being as chemically close to one another as you can get, but still not exactly identical. This is almost certain to have some interesting implications for the mineralogy of exoplanets. I mean, sure, the bulk of terrestrial planets everywhere will very likely have crusts made out of some silicate mineral, but will it necessarily be Olivine? Could there be a planet out there whose crust is primarily Andalusite and Kyanite?
I haven't read much in either fiction or academic literature about exomineralogy, but the latter might simply be due to how recent my own interest in geology is — I have yet to earn my Rock-Licker‡ stripes.
‡ (Said with love & respect for geologists)
In the context of the games, the different chemical abundances of planets mostly inform if there's commercial mining activity on their surfaces, with interstellar civilisation having a somewhat ravenous appetite for rare-earths and platinum group metals. If the planet is one of the ones you have surface missions on, it can also inform what deposits you might find, which is of interest to a specific sidequest, but I digress.
Overall I think the terrestrial planets are quite believable in terms of their densities, all within a fairly reasonable 1.0 to 8.0 g/cm³ range (Earth's is 5.513 g/cm³), with a few notable exceptions that go upwards of 11.0 g/cm³, like Patatanlis in Han System/Gemini Sigma. I find it very hard to believe such a terrestrial world could be half as dense as Osmium. Its description does give enough margin for us to interpret it might be a Cthonian Planet, but even still... then again, planetology is not quite my area; my emphasis is on how they move, not what they're made of.
Speaking of how they move — planets' entries in Mass Effect are notoriously different from those in ME2 and 3 in that the overwhelming majority of them lack any information as to their orbital distance from their stars; they only list their orbital periods. Only 12 of those 41 systems contain a planet (or planets) with orbital distance information, and one of them is the Sol System.
The sample size is relatively small, but as I was calculating planetary keplerian ratios and the stellar masses, I got the distinct feeling that almost all systems with a habitable planet have a central star of 1 Solar Mass. As in, exactly 1. That's obviously not something I can definitely prove, of course, as the relative uncertainties in the keplerian ratios are too high, but... it fits too cleanly in those systems with multiple calculable keplerian ratios for me to ignore. Something that bears investigating in future games, for those systems that show up on ME2 or ME3.
Vigil
But finally, without further ado, what you're all here for: the collected system data from Mass Effect, all dutifully and carefully annotated and collated in one place.
I have done my very best to transcribe the information down as exactly as I could — there are many things I could have changed for better comprehension or to standardise things or even to correct obvious mistakes, but that wasn't my goal. Do not get me wrong, I very much intend to do a deep dive in this and fix and change things at some point, but this document is intended as a source, not a derivative work — a document people can refer to when doing their own subsequent projects. It, therefore, needed to be as close to the in-game info as I could make it.
I have taken care to make it very clear what was put down in the doc by myself and what is directly extracted from the games. All of my own additions and observations are clearly marked as such, and the Appendix goes in-depth on how the process of making the doc was, including the maths used to calculate the derived planetary parameters and their uncertainties.
It is also important to note that, as the information was transcribed verbatim from the map, certain information, especially that pertaining to the arrangement of Clusters and their connections, does not entirely match the in-game fiction. Consider: the Charon mass relay in the Solar System (Local Cluster) is said to lead to the Arcturus System and that system alone, and yet in-game the Local Cluster links directly to Exodus Cluster, skipping the Arcturus Stream altogether. I have made no attempt whatsoever to fix this — that's for Part IV of this series of posts!
The link to the Google Doc with the information is: https://docs.google.com/document/d/1VhH2mtYWwJSQbHWCcLkWUSTD2jhtumEpNuY40SZYZtg/edit?usp=sharing
Comments are disabled on the doc itself, but feel free to leave your own comments and thoughts down on this post!
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And with all that done, the next post in this series shouldn't take too long, all things going well. All data for ME2 is already compiled, I just need to finish going through it and then format the doc for release, which should be very straight-forwards now that I've already figured it out for this first one.
There might be a few, non-Mass Effect posts on the Blog in between these two entries, but we'll see. In either case, until then!
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