Map of the known universe

• Distances. All catalogued distances are published measured values. For each one, the panel states the source, the number of significant figures, and the uncertainty where it exceeds five per cent.
• Planet positions. J2000 Keplerian elements from the JPL table, solved iteratively, with time derived from today's date. When you open the map, the planets really are where they stand.
• The Sun's position in the Galaxy. 8 178 parsecs from the centre, 20,8 parsecs above the plane. Spiral-arm geometry from maser parallax measurements.
• Body size ratios. Diameters are shown in true proportion to distances. Seen at the scale of the whole system, the planets are therefore invisible — that's the point, not a bug.
• Measurement. Calculated from the original coordinates in metres, in three dimensions, using the planets' instantaneous positions at the given time.

• Individual stars. Apart from the catalogued objects, everything else is statistical filler with a realistic distribution, but these are not specific, real stars.
• Planet textures. Generated procedurally in the browser. The continents on “Earth” are not our own, and the meridians don't match reality.
• The Oort cloud. No one has ever observed it. Both its location and density are estimated from the orbits of long-period comets.
• Cosmic microwave background. The sphere has the correct radius, but the pattern of spots is noise, not the actual Planck mission map, and its contrast is exaggerated many times over.
• The cosmic web. The nodes and filaments are procedural, and their density decreases with radius so the web stays legible at every scale.

The app doesn't hide this distinction — every object's panel states whether it's a measurement or a model.

Drag with the mouse	rotate the scene
Wheel or two fingers	change the scale
Ladder on the left	direct scale slider with a runner
+ − ↑ ↓	zoom in and out
← →	rotate
M	measuring mode
L	labels
Tab	next object in the current layer
Esc	exit measuring or close the panel

The bottom stop rail runs from Earth to the observable universe. The map's state is written into the page address, so the link can be shared complete with any measurements you've made.

The entire state of the map is a single number — the base-10 logarithm of the view radius in metres, ranging from 6,3 to 26,9. That's twenty orders of magnitude, from two thousand kilometres to eighty billion light years.

All coordinates are stored in metres as 64-bit numbers. Only the ratio of a coordinate to the view radius is sent to the graphics card, so the GPU never sees a number larger, in order of magnitude, than single digits. The camera stays put and only rotates — zooming isn't camera movement, it's a change in radius.

The solar-system layer additionally shifts its origin to whichever body is currently in focus. That's how you can descend all the way to the surface of the Earth without precision falling apart.

One thing to watch for: above roughly 100 megaparsecs, distance divided by the speed of light is no longer the light travel time. Both the panel and the measuring tool flag this. The “enlarge bodies” switch inflates any body smaller than 2,6 pixels so it stays visible — while it's on, a red label reports it.