What is the empty focus?
An ellipse has not focus but two foci, one at each end. Kepler’s laws specify the Sun focus of the planet’s elliptical orbit.
The other focus of the elliptical orbit is referred to as the empty focus. The distance between the empty focus and the aphelion point is equal to the distance between the sun and the perihelion point.
Which planet has a red spot?
Jupiter has a large red spot which keeps shifting and changing. The spot is believed to be an area of permanent turbulence.