Hiding gluSPhere()

i am creating a gluSphere, translating it and rotating it around y-axis(has a motion like a planet). i want the sphere to become invisible at certain point and have it reappear later.
how do i do that? i wud appreciate any suggestions

Someone has answered your question in the beginner forum. What was wrong with the answer?

>Just do not render it and keep track of where it is

how do i keep track of where it is?

how do i interpret the returned matrix to get the current position of the sphere?

any suggestions?