comet

i thought you were a star,
a constellation,
a planet,
fixed and dependable,
you would always be there,
shifting location slightly,
from season to season,
but never lost to view,
i was guided by your position,
everywhere i went,
oriented by your existence,
i only learned the truth,
after the fact,
when your trail was cold,
and only specks of minerals,
were left in your wake,
you were a comet,
and it was your passage that i witnessed,
uncomprehending,
not paying enough attention to every moment,
it never occurred to me,
they were numbered,
finite,
and would come to an end,
i am left with just one question,
just what part of forever did you not understand?