Which planet has the greatest difference between its closest and farthest distance from the Sun among the major planets?

Mercury's orbit is the most stretched out of any major planet, so its distance from the Sun changes the most in proportion to its average distance. At perihelion it comes much closer to the Sun than at aphelion, producing the largest orbital variation among the eight planets. This unusual path affects Mercury's temperatures and helped make it a key object in the history of celestial mechanics. Its orbit is one reason the planet experiences extreme surface heating.