Elliptical Orbits: Kepler’s First and Second Laws

Theory

1st law: orbits are ellipses with the star at one focus. 2nd law: the radius vector sweeps equal areas in equal times — so the body speeds up at perihelion. Below circular speed you get an ellipse; above $\sqrt{2}{v}_{circ}$ the body escapes.

What to observe

• The comet races near the star and crawls far from it.

Try this

• Select the planet and increase vx/vy until it escapes.

Also available in: Órbitas elípticas: 1ª e 2ª leis de Kepler (Português) · Órbitas elípticas: 1.ª y 2.ª leyes de Kepler (Español)