system-layout

Where everything in a star system goes, as numbers: how far out each planet is drawn, how big, how fast it goes round, its moons, and the asteroid belt. Pure: the star system draws what this says.

A real system is almost all empty space: drawn to scale, the planets are specks a long way apart and there is nothing to look at. So this lies, in documented ways:

• Distances are logarithmic. Each doubling of distance from the star adds the same step, so an inner system of rocks and an outer one of giants both fit on screen. The order is kept, and so is "much further out".
• Sizes are compressed by a square root. A giant is still visibly bigger than a rock, but not so big that the rock vanishes beside it.
• Planets never crowd. Each takes as much room as its moons need, and the next planet out starts beyond that.
• The belt is wildly overpopulated. A real asteroid belt is so sparse that you would see nothing from inside it; this one is a band of rock you can see, with its few large bodies picked out as bodies of their own.
• Periods follow Kepler (a cube law in the real distance), sped up so a year takes about a minute.

Everything follows from each body's seed, so the same system lays out the same way every time.