Eccentricity and elliptical orbits

Explore ellipse eccentricity and idealized elliptical orbits through exact geometry. Reconstruct semiaxes and focal offsets, compare shapes independently of scale, and recover orbit parameters from nearest and farthest distances to an occupied focus. Single-select and multiselect questions emphasize the circular limit, center-versus-focus distinctions, model assumptions and dimensionally correct calculations. Detailed explanations connect each answer to a check of the underlying ellipse.