We were having a discussion in class the other day about perihelion (the Earth's closest distance to the sun) and aphelion (the Earth's furthest distance from the sun.
The season's here on earth are due to the tilt of the Earth's axis and not the relative distance from the sun. We are actually closest to the sun in January which is winter in the Northern Hemisphere, and the furthest in July.
While all planets follow an elliptical orbit, the distance between aphelion and perihelion differs greatly.
Check out the link below and scroll to the bottom of the page. You will find a graph charting the differences in aphelion and perihelion for different celestial bodies in our solar system. It becomes easy to see why Pluto was downgraded from "planet" to "dwarf planet."
Check out the link below for some mind bending optical illusions!