Computer diagram showing the elliptical orbit of the Earth around the Sun. Earth's orbit is not a perfect circle, but rather an ellipse. However, with an eccentricity of just 0.0167, the disparity from circularity is very minimal, and to a first approximation the orbit can be described as circular. The closed circle in the diagram indicates perihelion, when the Earth is closest to the Sun (147, 098, 290 kilometres or 91, 402, 640 miles). It occurs around January 3. The open circle shows the opposite situation, aphelion, when the Earth is 5 million km (3 million miles) further at 152, 098, 232 kilometres (94, 509, 460 miles). Aphelion occurs around July 4.