Complex sentence: Suppose a tunnel is dug from one end of the Earth to the other end straight through its center; then, assuming the Earth's internal mass density is constant, a stone dropped in such a tunnel oscillates harmonically with Schuler's time constant.
Split into simpler sentences: Suppose a tunnel is dug from one end of the Earth to the other end straight through its center. A stone dropped in such a tunnel oscillates harmonically with Schuler's time constant.