Three sliders: choosing what to see

The solar-system.html view has three sliders in the Échelle / Scale sidebar section. Each one controls a different aspect of how the scene maps physical reality to pixels on your screen. They’re independent — you can mix and match.

Body size — relative proportions

At 0 (default, leftmost): stylised values from the view’s internal planet table. Jupiter is drawn at about 3.5× the size of Earth. That’s much smaller than reality (real Jupiter is 11× Earth) but it keeps Mercury, Mars, and the other small planets visible alongside the gas giants.

At 100 (rightmost): real proportions from NASA fact sheets. Jupiter becomes 11× Earth, Saturn 9.1×, Neptune 3.9×, and so on. Earth stays anchored at 1 world unit either way.

This slider is about ratios between planets. Think: “is Jupiter exaggerated compared to Earth, or is the actual ratio used?”

Distance between bodies — orbital scale

At 0 (default): compressed distances. Mercury at 8 world units from the Sun, Neptune at 74. The whole system fits in the default camera view. Inner-planet spacing and outer-planet spacing have been independently squashed so all 8 planets stay visible at once.

At 100: real distances. The orbital ruler is 1 AU = 15 world units, calibrated on Earth’s orbit. Mercury moves in to ~5.8, Neptune stretches out to ~451. You’ll need to zoom out (or pan a long way) to see Neptune. This is roughly what the dedicated scale.html view shows for distances.

Exaggeration — overall planet inflation

At 100 (default, middle): current behavior. All planet radii are inflated by an implicit factor of ~1500× relative to the orbital ruler. This is the only reason planets are visible at all — without it, Earth would be 1/1500 of a unit (sub-pixel) at distance=100. The exaggeration is what makes solar-system images “work” pedagogically.

At 0 (leftmost): strict scale — the inflation goes to zero. Planets collapse to sub-pixel dots. They’re still there, but you can’t see them as spheres anymore. The colored glow markers (small fixed-pixel circles around each planet) take over so you can locate the planets even when their actual rendered size is below one pixel.

At 200 (rightmost): double the default exaggeration. Cinematic — Jupiter looms larger than usual, Saturn’s rings dominate the frame. Useful for video capture or when showing a single planet at presentation scale.

Body size vs exaggeration — the difference

Both affect how big planets look on screen, but at different levels:

A useful analogy: think of a stereo. Body size is the equaliser — it adjusts the balance between frequencies. Exaggeration is the overall volume — it makes everything louder or quieter at once.

Seeing the solar system at true scale

To see the solar system at its actual physical proportions:

1. Distance → 100 (real orbital distances, 1 AU = 15 world units)
2. Body size → 100 (real planet ratios, anchored on Earth)
3. Exaggeration → 0 (no inflation; the size and distance rulers agree)

At this combination, planets are dots in a vast emptiness. You’ll need to zoom in significantly to see any single planet as a sphere, and most will only be visible via their fixed-pixel marker glow. This is true scale. It’s why almost every educational image of the solar system you’ve ever seen “cheats” with implicit exaggeration — without it, there’s almost nothing to look at.

The dedicated scale.html view shows this same proportional reality from a fixed configuration. The three sliders in solar-system.html let you dial between the visible-but-stylised view (defaults) and the honest-but-empty view (sliders maxed, exaggeration at 0), with everything in between.

For the technical breakdown of how each slider maps to physics — including the derivation of the ~1500× ratio and the piecewise log-then-linear mapping of the exaggeration axis — see scales.md.