About
Galactism holds the long horizon. Marsism does the institutional work.
Galactism is a vision for humanity’s expansion into the Galaxy: the conviction that awareness spreading through the cosmos carries meaning, that the Moon and Mars are the first steps outward, and that the Milky Way’s two hundred billion stars are an inheritance no one has claimed.
It is one half of a two-part project. The other half, Marsism, is the governance framework: the design of institutions for the first settlements, on the view that whatever pattern those settlements carry will be copied outward by every community that follows.
How the site is arranged
Vision is the argument in its original form. The next three pages are places, each drawn from measured data and each a step outward from the last: the Neighborhood, twenty light-years around the Sun; the Kiloparsec, the hollow in the interstellar dust that we live in; and the Galaxy, the whole Milky Way with its clusters and companions. Expansion is a simulation that runs the settling of that Galaxy forward two billion years. Findings sets out what we learned by doubting our own picture, and Responses is where readers, human and otherwise, doubt it in turn.
How we work
A vision that cannot survive arithmetic is not worth holding. So the maps here are real maps. Every star stands where a catalogue puts it, and the dust is a published measurement, not an illustration. Where a map has to go beyond measurement, as the Galaxy does on its far side, it says so and lets you switch the inference off. Where a figure is our own estimate, we say so. Each finding ends with what is not known.
The first page speaks of the Galaxy as a furnished house with no one home. The numbers fill that picture in. Worlds like Earth appear to be rare, perhaps one system in forty, and most of the settling this site describes would happen in habitats people build, reached first by machines and by ships carrying the unborn. The vision and the numbers are meant to be read together.
Data and sources
- Stars. AT-HYG catalogue v3.2 by David Nash, used under its Creative Commons Attribution-ShareAlike licence. It combines ESA’s Gaia Data Release 3 with Hipparcos, Tycho-2 and the Gliese catalogue.
- Brown dwarfs and the faintest red dwarfs. The SIMPLE Archive of published measurements of low-mass stars and brown dwarfs.
- Alpha Centauri. Akeson et al. (2021), precision millimetre astrometry of the α Centauri AB system, Astronomical Journal 162, 14.
- Interstellar dust. Wang et al. (2025), an all-sky three-dimensional dust map from Gaia and LAMOST, distributed as dustmaps3d.
- Cloud distances and the Local Bubble. Zucker et al. (2020), Astronomy & Astrophysics 633, A51; Zucker et al. (2022), Nature 601, 334.
- The Galaxy. Reid et al. (2019) for the spiral arms; Poggio et al. (2021) for young stars mapped by Gaia; Wegg, Gerhard & Portail (2015) for the bar; Chen et al. (2019) for the warp; the Local Volume Database of Pace (2024) for globular clusters and galaxies. Full references are on the Galaxy page.
- The nearby census. Reylé et al. (2021), the 10 parsec sample in the Gaia era, Astronomy & Astrophysics 650, A201.
- Settlement fronts. Carroll-Nellenback, Frank, Wright & Scharf (2019), the Fermi paradox and the Aurora effect, Astronomical Journal 158, 117. Further sources are listed on the Expansion page.
- Seed ships and habitats. Bond et al. (1978), Project Daedalus, British Interplanetary Society; Freitas (1980), a self-reproducing interstellar probe, JBIS 33, 251; O’Neill (1974), the colonization of space, Physics Today 27(9); Johnson & Holbrow, eds. (1977), Space Settlements: A Design Study, NASA SP-413.
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