By Oleksandr Koliakin
Kepler's second law of planetary motion, according to "Sciencia" is:
A line drawn from the sun to the planet sweeps out equal areas in equal times.
If we have an object with a highly elliptical orbit, it would be easier to observe this effect. When this object is far from the focus around which it orbits, it would move slower. When it is closer to the focus, it would move faster. Here is a diagram to demonstrate this law:
Sources:
Sciencia (book)