This month as the Earth continues its annual trek around the Sun it reaches a point in its orbit that is called perihelion.
This is the minimum distance that separates the Earth from the Sun, and we are the closest to the Sun for the year at this point in the orbit.
Approximately one-half year or one-half revolution later, during the first few days of July, the Earth is at aphelion, its maximum distance from the Sun.
This is due to the shape of the Earth's orbit being elliptical rather than circular. However the Earth has an
mildly elliptically-shaped orbit that is closer to being slightly out-of-round than the incorrect, very elliptical orbit that is often shown,
looking more or less like the illustration used here.
To read more about this and get some teaching ideas click here to
download a PDF copy of my January 2010 Scope on the Skies column "Solar Explorations".
