Project Hail Mary and StarForce: Alpha Centauri

David A. Wheeler

2021-10-26

Project Hail Mary is a 2021 science fiction novel by Andy Weir - and a really good one. StarForce: Alpha Centauri is a board game published in 1974 by Simulations Publications Inc. (SPI). Here I'm going to show how the stellar objects noted in the novel relate to the StarForce game board. If you want to see a map that more accurately shows the locations of the real-world objects, see my page showing a Project Hail Mary Stellar Map.

Warning: Spoilers for the novel Project Hail Mary are ahead! If you haven't read the novel, do that first, you'll be glad you did.

StarForce is an unusual board wargame, and not just because it has a science fiction setting. Its main game map (what it calls the "Stellar Display") is a 3-dimensional volume of the real stars within 20 light years of Earth, with star positions based on actual astronomical positions. Creating a 3-D map using a 2-D board is an interesting trick. The game map is a map of many hexagons (hexes) where each hex represents a one light year column and Sol (our star) is at the center. Three-dimensional positions, aka coordinates or LiteZulus, are identified by a 4-digit 2D position (identifying a hex), a slash, and a number indicating the number of light-years above or below the equatorial plane (image). SPIGames has posted the StarForce rulebook and a sample ad. Redmond Simonsen, designer of StarForce, said that "There were a couple of liberties taken with the positions of some stars, but, by and large, the map is pretty accurate astronomically. There are a few stars a couple of light years out of line." [THE STARFORCE TAPES: A Three Way Discussion of the Design and Rationale of StarForce]. So while it's not 100% accurate, it's unusually accurate and its simple map makes it easy to see relative positions of stars in our stellar neighborhood in a way that isn't normally accessible to the public. I like looking at the map without even playing because it gives a sense of our stellar neighborhood that isn't as clear otherwise. It's fun to play, too.

The novel Project Hail Mary mentions a number of stellar objects relatively near Earth, and it turns out you can find almost all of them on the StarForce game map. Here we'll look at important aspects of the novel through the lens of the StarForce game map. This means you can better understand the novel using a StarForce board and this article.

As you follow the novel's plot, it's eventually revealed that Tau Ceti is the origin of astrophage. On page 95-96 of the hardcover 2021 release, it's revealed that astrophage spread as follows (here I provide their StarForce coordinates):

WISE 0855-0714 (full designation WISE J085510.83-071442.5) is not on the StarForce map for a very simple reason: this object was discovered in April 2014, but the game (with its map) is copyright 1974. It might not have been put on the StarForce map, even if it had been known at the time, because of its small mass. It is only 3-10 Jupiter masses (MJ). Normal hydrogen thermonuclear fusion reactions require .08 mass of the Sun - so a main-sequence ("normal") star requires at least around 89 Jupiter masses, and WISE 0855-0714 is nowhere near that. Its mass is even below 13 Jupiter masses, the minimum (limiting) mass for thermonuclear fusion of deuterium that is necessary to create a brown dwarf. In short, its mass is so low that it can't fuse any atoms like a main-sequence star or a brown dwarf. Its temperature is not like a typical star either: -48 to -13 °C (-55 to 8 °F). Objects like these are often classified as a sub-brown dwarf. It's easy to quibble about categories. However, since it can't fuse any atoms, it's more like a massive rogue planet than a star in the usual sense, and that might have disqualified it from being placed on the board. After all, the StarForce game repeatedly refers to all the map objects as stars. For example, its glossary defines "star system" as "any one of the variously colored discs on the Stellar Display". In short: the game's creators might have omitted this object even if they had known about it. If it was on the StarForce map, I've determined that WISE 0855-0714 would be at StarForce coordinate 1415/-1. See the lengthy justification below for how I found this coordinate.

The novel never says astrophage spread from Tau Ceti directly to Epsilon Eridani, so in theory there could have been an intermediary. However, a look at the StarForce map shows that these two stars are relatively close together, so direct transmission is by far the most likely scenario.

The novel mentions that at least 3 other stars were infected by WISE 0855-0714:

When considering the fictional situation, WISE 0855-0714 has such a low temperature that it's a wonder that astrophage managed to both spread to it and then far from it. It would have taken far longer for astrophage to have gathered energy from this rogue planet instead of its usual diet of stars. I haven't tried to calculate that, but I suspect it would be a very long time. Perhaps it's best if we don't examine this question too closely :-).

Rocky and the other Eridians come from 40 Eridani, StarForce coordinate 2707/-2. The StarForce coordinates of 40 Eridani and Tau Ceti are 10 light-years apart, and if that's accurate, that is larger than the 8 light-year transmission range of astrophage. An especially likely transmission route, if we just look at the StarForce map, is from Tau Ceti (3015/-3) to Epsilon Eridani (2713/-2) to 40 Eridani (2707/-2). The book clearly states that Epsilon Eridani was infected, after all. Since Sol also eventually became infected through Epsilon Eridani, this suggests that 40 Eridani would probably have become infected long before Sol. That is consistent with the novel's plot, which implies that 40 Eridani was infected before Sol (with a hat-tip to Einstein acknowledging that "before" is a complicated word when dealing with speeds approaching the speed of light). After all, Rocky arrives first even though Earthlings have somewhat more advanced technology, detect the problem on Sol quickly, and created a starship and its fuel relatively rapidly.

It's impressive to see the care that went into making this novel given what we know at the time of its writing. We can quibble about some things, but all of this suggests careful crafting of the story.

As an aside, there are other maps of nearby stellar objects if you're curious. Stars within 20 light years tries to show similar information to the StarForce map, focusing on accuracy. The Wikipedia page List of nearest stars and brown dwarfs shares similar information. Although it's less accurate (in part because everything is forced onto a grid), I still find the StarForce map easier to understand.

Here's another aside, and a quirky one at that. Some sites such as Songfacts report that the English synth-pop band The Human League was named after one of the factions in StarForce. The Human League (HL) first appears in StarForce scenario 3, where the Human League arises and challenges the Pan-Human Hegemony (PHH). In StarForce scenario 3 the human league (HL) controls Tau Ceti (3015/-3), Epsilon Eridani (2713/-2), and 82 Eridani (3009/-14), while the Pan-Human Hegemony (PHH) controls Sol (2020/0) and Alpha Centauri (1821/-4). Tau Ceti (HL) and Sol (PHH) have the most starting StarForces in both scenarios 3 and 6, so in StarForce those star systems appear to be their respective "capitals". The band's song "Don't You Want Me" hit #1 on July 3, 1982, so there's a chance you've heard this song by The Human League. You can see the official music video of "Don't You Want Me" by The Human League. Other hits from the band include "(Keep Feeling) Fascination" and "Human".

In sum: we can find all of the stellar objects in the novel on the StarForce game map from 1974, with one exception. That exception is WISE 0855-017, which was discovered in April 2014 (about 40 years later). I think that's pretty neat.


Appendix: Locating WISE 0855-0714 on the StarForce map

Here's how I located WISE 0855-0714 on the StarForce map. Wikipedia tells us that this object is 7.43 light-years away, has a right ascension of 08h 55m 10.83s (133.795125 degrees), and a declination of -07° 14′ 42.5″ (-7.245139 degrees), using the equatorial center-of-earth (geocentric) J2000.0 astronomical coordinate system. The International Celestial Reference System (ICRS) is the current standard celestial reference system adopted by the International Astronomical Union (IAU), but it was designed to have approximately the same results as J2000.0 (the change from J2000.0 is that ICRS is based on far-away quasars so it will not have to significantly change for a very long time). For our purposes we can assume they're identical. I don't know for certain what coordinate system was used to create the StarForce map, but I believe it used an equatorial geocentric coordinate system using B1950.0 (Besselian years) instead because that was common at the time. The dates are specified because of Earth's precession. However, the difference between B1950.0 and J2000.0 shouldn't matter in this case. It takes Earth about 25,800 years to precess (so 50 years is a tiny fraction of this time), this is a relatively nearby object (so errors will have a smaller effect), and we only need to get a value to the nearest light-year anyway. I looked at the location of Sirius - right ascension 06h 45m 08.917s (101.29°), declination -16° 42′ 58.02″, 8.6 light-years away in J2000 - and compared that to its StarForce coordinate 1812/-2. I also looked at Eta Cassiopeiae - right ascension 00h 49m 06.29070s (12.28°), declination +57° 48′ 54.6758″, distance 19.42 light-years - and compared that to its StarForce coordinate 3018/+15. Given those sample points, I realized that a right ascension of 0h is "due east" on the map, and it rotates counterclockwise through a 24-hour day, with positive declination going up and negative declination going down.

As noted earlier, WISE 0855-0714's right ascension is 133.795125 degrees counterclockwise. and its declination (dec) is -7.245139 degrees. Using basic trigonometry we can compute that its horizontal distance on the equatorial plane is 7.43 * cos(dec) = 7.37 light years, while its absolute vertical depth is 7.43 * sin(dec) = 0.93 light-years. Its declination goes down, so it's actually -0.93 light-years. We'll assume hexes are vertically centered (e.g., Sol's coordinate 2020/0 covers depths -0.5 to +0.5), so a depth of -0.93 light-years turns into a depth of -1 in the map (because that coordinate covers depths of -0.5 through -1.5). You can see the details of these trigonometric calculations if you wish. Each hex that represents one light-year is 5/8" side-to-side (measured flat side to flat side). so on the map we need to go 7.37 ly * (5/8")/ly = 4.60625" = 4 5/8". Using a protractor and ruler we can then find the hex position by starting from the center of Sol and going 4 5/8" at 133.795125 degrees (counterclockwise). I've measured several times and this appears to lead us to hex 1415 (in a spot very close to hex 1414).

Is the distance right? It turns out there are some oddities. From Sol we wanted to measure out 7 light-years horizontally and 1 vertically. The StarForce distance table says that's 7 total, which is correct for a rounded distance of 7.43 light-years. But if we count out the hexes we find the distance is is 8 light-years horizontally and 1 light-year vertically, for a full distance of 8 light-years. That doesn't seem right; the actual distance is 7.43 light-years, but counting up the hexes gives us a distance of 8. Did we do anything wrong? I don't think so. If you measure 4 5/8" distance directly north, you get 7 hexes, which would be what we expect, so the length seems correct. The mystery is cleared up once you realize that this map is a set of hexes, and distances on the map are calculated by counting integer distances 1 light-year apart. Hex grids with North/South flat faces, like this one, are exact for angles of exactly 30, 90, 150, 210, and 270 degrees. Unfortunately this particular object isn't at one of those angles; it's at 133.795125 degrees, almost halfway between 90 and 150 degrees. As a result, this object is close to the worst possible case for approximating distance by counting hexes. Basically, a spaceship that can only go one light-year at a time, in only one of 6 angles, will take a jagged path and perceive a larger total distance than a spaceship that could do the jump all at once. The game map, unfortunately, forces us to estimate distances the first way. Using hex 1414 would be even worse (that would be 9 light-years away horizontally from Sol when counting hexes, instead of 8).

So here I'm going to use the hex position that best represents its actual position, even though the rules for computing distance will produce a slightly larger distance from Sol than it will have in reality. The same slight error in distance happens to all other stellar objects when their angles are not near the six exact angles of hexagons. It's a minor error caused by their efforts to emphasize playability over exact astronomical accuracy.

The answer? WISE 0855-0714 appears to be best represented as being at the StarForce coordinate 1415/-1.


You might also want to see the related page Project Hail Mary Stellar Map, where I place the information about Project Hail Mary onto a map of where the stellar objects actually are. Feel free to see my home page at https://dwheeler.com.

(C) Copyright 2021 David A. Wheeler. Released under Creative Commons Attribution-ShareAlike version 3.0 or later (CC-BY-SA-3.0+).