Let discuss it according to the second law of Kapler's " Every planet covers equal area in equal time of period" what does mean it so that very simple theory for understanding Kapler's second law says that every planet travel equal area on its elliptical path in equal time of period.
By the first law of kapler' every planet moves in a elliptical orbit and we know ellipse does not have a certain focus or centre like a sphere, ellipse have two focus and sun could be at anyone out of two when a planet being near the sun its mean radius from sun is small so that the covered area by planet would be small so as for as a planet goes away from the sun its mean radius increase obviously the covered area is also increase so if a planet moving near the sun the covered area would be small and when it moving far away the the sun covered area by planet would be large but that's not happen.
Because planet does not moving with a constant velocity around sun.
When a planet be near the sun it has extreme velocity as far as it goes away from the sun its velocity is decreased that's the reason it covers equal area in equal time period and this velocity by which it covers area knows as Areal velocity of planet.
