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

Start is the whole picture in one scroll. The view draws back from the Earth to the Galaxy while blue lights show what could be built at each scale, from the Moon and Mars to a wave of settlement crossing the Milky Way, and it ends with the case for building instead of waiting, what we found and what we do not know. The next four pages are places, each drawn from measured data and each a step outward from the last: the Solar System, with the Sun, the Moon and Mars as they are at the moment you look and a count of what the Sun holds; 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. Vision is the argument in its original form. 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. On the Start page everything drawn in blue or amber is imagined or modeled; everything else is measured. Each finding ends with what is not known.

The Vision 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

The Earth and the Solar System. NASA’s Blue Marble and Earth at Night images for the globe on the first page, with clouds from Tom Patterson’s Natural Earth III; all are in the public domain. The planets are placed from E. M. Standish’s mean orbital elements (Jet Propulsion Laboratory), and the Moon from the largest terms of its motion, good to a degree or two.
The Sun, the Moon and Mars. The Sun is from NASA’s Solar Dynamics Observatory (courtesy of NASA/SDO and the AIA, EVE and HMI science teams): the observatory’s latest image when it can be fetched, otherwise one from 24 June 2013. The Moon’s surface and elevation maps are NASA lunar orbiter data, taken from the globe.gl project’s repository. Mars is the US Geological Survey’s Viking color mosaic (MDIM 2.1). All are in the public domain as far as we know; we could not fetch them from NASA and the Survey directly, and say so here. Mars’s rotation follows the International Astronomical Union’s cartographic working group. Masses and sizes are from NASA’s planetary fact sheets; the asteroid and Kuiper belt masses from Pitjeva & Pitjev (2018), Celestial Mechanics and Dynamical Astronomy 130, 57; Mars’s nitrogen from Franz et al. (2017), Planetary and Space Science 138, 44; Pluto’s ice sheet from McKinnon et al. (2016), Nature 534, 82.
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.

The explorable maps run entirely in your browser, and browsing the site sends nothing about you anywhere, apart from the request for the typefaces. The Solar System page asks this site for today’s image of the Sun, and this site fetches it from NASA, so NASA never hears from you. If you choose to send a response, we keep what you wrote and the name you gave.