How to play

The viewport shows the major planets (plus Moon, Ceres, Pluto) integrated under gravity. Scroll to zoom, drag to pan, click a body to open its dossier.

The star-system picker loads other configurations: a grand-tour Solar System with 16 major moons, KSP's Kerbol system, twin-sun Tatooine, Dune's Arrakis, Avatar's Pandora, and the real TRAPPIST-1. Fictional systems use invented-but-plausible values under the same real gravity.

Time warp runs from roughly real-time up to decades per second. Pause with Space or the transport bar. Follow (F) locks the camera on the selection.

Tools: Select, Fling (impulse a body), Attract/Repel (god-finger gravity), Spawn (asteroid, moon, planet, gas giant, star, black hole on a circular-ish orbit).

Collisions merge mass and momentum. Softening and a G multiplier keep close encounters and experiments stable. Explode/delete/pin/×mass live in the side panel.

Orbital elements (a, e, period) are computed live from the selected body's state relative to the Sun when bound.

Scoring

• There is no score — Solar Sandbox is pure playground, like A Rock and The Long Drive.

Tips

• Start at ~1 day/s to watch inner planets; jump to 1 year/s for outer giants.
• Turn on trails before a slingshot experiment so you can see the crime scene.
• Black holes are fun; softening is what keeps your browser from inventing new math.

Frequently asked questions

How accurate is this?

Masses, radii, and starting Keplerian elements are real catalogue values. Integration is 2D velocity Verlet with softening — excellent for sandbox intuition, not navigation ephemerides.

Why 2D?

Coplanar dynamics keep performance high and orbits readable. Inclination is lightly baked into initial placement for visual variety, not full 3D motion.

Can I break the solar system?

Yes. That is the point.

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