The Case for Space: A Longtermist Alternative to Existential Threat Reduction

This is my first post, so all crit­i­cism is wel­come. I will as­sume that the reader already agrees with util­i­tar­i­anism. I will ar­gue that if ex­is­ten­tial threats are not able to have their risks min­i­mized in any mean­ingful way(I do not be­lieve there is a way to do so), that space ac­cel­er­a­tionism or “Spacism” as I will call it, is a vi­able can­di­date for the most effec­tive way to be al­tru­is­tic.

I will be­gin with a cou­ple as­sump­tions.

  1. Civ­i­liza­tion will not end

  2. No cur­rently physics-break­ing sci­ence is dis­cov­ered (faster than light space travel, in­finite en­ergy, or the like)

With there 2 con­di­tions met, I would say it is safe to as­sume that hu­man­ity (or what­ever takes our place) will colonize the galaxy and lo­cal group. Sim­ply put, given enough time, Earth would have prac­ti­cally no rea­son to not launch a sin­gle von Neu­mann probe that would even­tu­ally set­tle the reach­able uni­verse for us.

I will now do some math to calcu­late a mag­ni­tude of souls that could ex­ist on a cos­mic scale. I will use very con­ser­va­tive es­ti­mates wher­ever ap­pli­ca­ble.

There are around 100 billion stars in the milky way alone, and over a trillion more stars will be­come within our reach af­ter the An­dromeda col­lides and the lo­cal group merges. I will round this down to a trillion.

We cur­rently do not know how many planets the av­er­age star has, likely up­wards of one, but I will use an es­ti­mate of 1 planet each. We also do not know the av­er­age size of a planet, so I will use our small­est planet (Mer­cury) for calcu­la­tions. Most planets are not hab­it­able, how­ever that is largely ir­rele­vant as a much more effi­cient use of the re­sources would be to con­vert them into habitats in­stead of liv­ing on the sur­face.

We cur­rently do not have any real sci­en­tists calcu­lat­ing how many habitats an Mer­cury-sized planet could pro­duce, so I used some vol­u­met­ric calcu­la­tions and ob­scenely in­effi­cient re­source us­age. If we turned Mer­cury into O’Neil Cylin­ders 20km across with a 10km di­ame­ter in­te­rior (5km thick walls), we would have around 15x the sur­face area of earth to use.

Our fi­nal as­sump­tion is that Earth as it is now is our peak lay­out, and 15 earths worth of sur­face area can hold 15 times earth’s cur­rent pop­u­la­tion.

Now let’s mul­ti­ply;

Peo­ple per Earth Sur­face Area: 7500000000

Earth Sur­face Area Per Star: 15
Stars: 1000000000000

Mul­ti­ply this out, and you get 112,500,000,000,000,000,000,000 peo­ple who can live with our re­sources. If we can speed up the set­tling of ev­ery star by one sec­ond, we will have as many ex­tra sec­onds of life as we have hu­mans. Com­pacted into years, speed­ing up the start of galac­tic coloniza­tion by one sec­ond will re­ward us with 3,500,000,000,000,000 years of hu­man life.

As I have men­tioned, I have used very con­ser­va­tive es­ti­mates wher­ever I could, there­fore the ac­tual num­ber is likely many or­ders of mag­ni­tude higher. Most planets we know of are much larger than Mer­cury. We will likely be able to cre­ate a habitat de­sign that will re­quire less than 7.5 km3 of ma­te­rial to build 1 km2 of liv­ing space. We will likely be able to lay­out liv­ing space more effi­ciently than Earth, which is mostly un­us­able wa­ter/​desert/​moun­tains. We may be able to mod­ify hu­mans to re­quire less re­sources and have a higher moral weight. Not to men­tion that it may be pos­si­ble to har­vest mat­ter from stars, and that fu­ture hu­mans will use the ex­tra time to pre­pare for the heat death of the uni­verse(fur­ther in­creas­ing their time’s util­ity). How­ever adding a few more ze­ros is not likely to con­vince any­one else, it may as well be in­finity.