I agree a tube of cocking was dropped inside (got stuck on a brick ledge or flue liners mortar) when a roofer was flashing around the chimney, then tubes plastic baked away and the material rounded in time with heat.

Fundamentally flawed, test needed to be airless gravitational traveling to earth’s core not earth’s center. Then (even if assuming earths center) their would be no excaping (other side) due to gravitational incremental increase multiplied by travels progression would include drag, the example fails to equate or match…