The point in the orbit
when the a planet is
closest to the sun is
called perihelion.  The
point when the planet is
furthest from the sun is
called the aphelion.
The planet orbits faster when it is closest to the
sun.  So perihelion is the point in the orbit when the
planet is traveling the fastest.  In the case of earth’s
orbit, perihelion occurs in early January, while
aphelion occurs in early July.  This is why our
calendar months have irregular lengths.  The planet
gets more sunshine at perihelion, and less at
aphelion, because of the inverse square law.