Ah. It's because it's easier to describe the motions of the
   planets that way.

   Yet, in common speech, we almost NEVER speak in heliocentric
   terms. I do sometimes just for fun.

   We speak in GEOCENTRIC terms.

   I don't expect that to change, unless we establish a base on the
   Sun. THEN those people will start talking in heliocentric terms.
   We THINK we know the sun is at the center, but all of our
   languages betray the truth: We know the Earth is at the center
   of the Universe. Even moreso, we tend to put OURSELVES at the
   center of the Universe. Rarely do we even see ourselves from
   another's perspective, unless it suits something that ALSO
   happens to be our own perspective as well.