How this map is built

Every star and galaxy sits at its real measured position, in one continuous space. There are no separate "levels", you are flying through a single 3D model on a logarithmic scale, so structures nest the way they truly do: the neighborhood inside the galaxy, the galaxy inside the cosmic web.

The stars are two catalogues drawn together, because neither contains the other. Nearly 96 million come from Gaia DR3, every one with a parallax measured to better than 10%; the remaining 2 million come from AT-HYG (Hipparcos, Tycho and Gaia). Gaia is blind to the very brightest stars — it saturates, and Vega and Altair have no usable parallax in it at all — while AT-HYG misses stars Gaia pins down to a thousandth of a parsec, Barnard's Star among them. Both are drawn, coloured by real temperature: hot blue-white giants, our yellow Sun, cool red Antares. They form a bubble a few thousand light years across, the limit of where stellar distances can actually be measured, including the real stars above and below the galactic plane.

Gaia measures 1.47 billion parallaxes, but 87% of them have a signal-to-noise below 5, where the inferred distance says more about the statistical prior than about the star. Those are sky positions, not distances, and they are deliberately excluded. What is left is the ~98 million whose distances are genuinely measured.

The galaxies come from two redshift surveys, 620,033 of them placed by their measured redshift through Hubble's law: the all-sky 2MASS survey for the local sphere, and the deep SDSS survey for the great wedge that reaches out past 500 million light years. The cosmic web, its filaments, walls and voids, is not drawn; it falls out of the data.

Between the galaxy and the deep web sits the Local Group and Local Supercluster: real nearby galaxies at their measured distances, Andromeda, the Magellanic Clouds, Centaurus A, the Whirlpool, and the Virgo Cluster that anchors our supercluster. The bright galaxies here are real, from the 2MASS Redshift Survey, weighted by their measured luminosity so cluster cores glow.

The glowing web at the supercluster scale is a reconstruction. A real survey is a sparse scatter of galaxies, not the continuous filaments you see in simulation images, so the soft web behind the real galaxies is modeled: the bright nodes sit at the true positions of Virgo, Coma, the Great Attractor and the other real clusters, and the filaments and voids between them come from a Voronoi-foam model of the cosmic web, boosted to follow the real 2MASS density. The structure is a plausible reconstruction, not an observation; the real galaxies ride on top of it.

The solar system is now every measured orbit. All 1,554,969 minor planets the IAU Minor Planet Center has an orbit for: the asteroid belt, the Jupiter Trojans, the Centaurs, the Kuiper belt, the scattered disc and the comets. These are not a representative cloud. Each point carries its own measured orbital elements and Kepler's equation is solved for it every frame, so the belt you see is genuinely orbiting. The observation arcs behind this data start with Ceres in 1801 and run to orbit updates issued this week.

The Oort cloud is the one thing out here nobody has ever catalogued. Not a single object in it has been directly observed, so that shell is drawn as a model and labelled as one. The real measured points that far out are the long-period comets: 97 have fitted aphelia beyond 1,000 AU, 37 beyond 10,000 AU, and the most distant reaches 101,397 AU before falling back. The heliopause is drawn blunt-nosed rather than spherical, because the interstellar wind compresses it to ~120 AU at the nose — where both Voyagers actually crossed — and draws it into a long tail behind. The two Voyager probes sit at their real 2026 positions, the only human-made objects out there. The far Milky Way is still a schematic spiral, because we sit inside our galaxy and cannot measure most of its stars; the real stars fill the bubble around the Sun, then blend into the model beyond.

"Enable realistic scaling" removes every visual aid at once. Normally each object is drawn at a readable size, because at true scale almost nothing in this map would be visible at all. Turn it on and everything is redrawn at its real angular diameter, with brightness falling off by the fraction of a pixel it actually covers. The asteroid belt disappears. Earth becomes about one eight-hundredth of a pixel. What is left is the honest picture: the universe is overwhelmingly empty, and the emptiness is the finding.

The halo is real again. Surrounding the disc, the roughly 150 globular clusters (Harris catalogue) and the dwarf satellite galaxies (Sagittarius, Fornax, Sculptor, Draco, Leo I and dozens more, from the McConnachie catalogue) sit at their real measured distances, filling the space from the disc edge out to the Local Group that would otherwise look empty.

The "AI fill" toggle is different from everything else: it is not real data. A 3D diffusion model I trained on simulated cosmic-web fields dreams up plausible galaxies to fill the sky the surveys never saw, behind the Milky Way and outside the SDSS wedge, so you can imagine what the whole cosmic web might look like. It is statistically web-like but invented; the crimson points are inferred, never observed.

The colour of the microwave background is not real. The CMB is a 2.725 K blackbody, and its hot and cold spots differ by about 100 microkelvin — a variation of roughly 0.004%. Rendering that as visible mottling means amplifying it about twenty-five thousand times. It is also microwave light, which no eye can see at all. The pattern is a real measurement; the colour is a convention for making an imperceptible variation visible.

Data: IAU Minor Planet Center (MPCORB, CometEls) · ESA Gaia DR3 · AT-HYG / HYG (astronexus, public domain) · 2MRS (Huchra et al. 2012) · SDSS · globular clusters (Harris 1996, 2010 ed.) · Local Group dwarfs (McConnachie 2012). Rendered with Three.js. Code on GitHub.