Orbit Explorer
Stretch an orbit from a circle to a comet-like ellipse.
Simplified two-body illustration. Real Kepler motion moves faster near the central body; this teaching model keeps the shape accurate but timing uniform. Gravity of other bodies, relativity and drag are omitted.
Model assumptions
Two-body Newtonian shape; timing simplified (see note under the canvas).
Reference: NASA planetary data; Newtonian mechanics. This is an educational model, not an ephemeris.