DATES or GRAPHIC Note: Distances are approximate and calculated from JPL ephemeris data. Pluto is a dwarf planet. Its eccentricity causes it to cross Neptune’s orbit. TEXT   In astronomy, perihelion and aphelion are the two extreme points in Earth’s elliptical orbit around the Sun. These terms also apply to any object orbiting the Sun or another star. Perihelion is the point where the object is nearest to the Sun, while aphelion is when it is farthest a