What is an Aphelion?
An aphelion is a moment in the point of a celestial body’s orbit around the Sun when the celestial body is furthest from the Sun. The opposite of an aphelion is a perihelion, when that object is closest to the Sun. Each of the objects which orbits the Sun experiences aphelion and perihelion at different points in time, and the difference between these two points can vary radically, depending on the eccentricity of the object’s orbit. While people often say that objects like Earth are “circling the Sun,” this terminology is technically not quite correct, because the objects in orbit around the Sun actually have elliptical orbits, as described by Kepler in his First Law. The amount of variance from a perfectly circular orbit is known as the “eccentricity” of the orbit. The higher the eccentricity, the more elliptical the orbit. Earth has a fairly low eccentricity, around .0167, by contrast with Mercury, with an eccentricity of .2056. In the case of Earth, aphelion falls in the Northern H
