Eric Olthwaite
Guest
It'll melt a long time before it gets to the core. A theoretical unmeltable weight, though, would overshoot the centre of the Earth a bit, but not all the way to NZ as it'd have lost energy to friction. Then it'd bounce back through the centre, part way back to Glossop and continue see-sawing smaller and smaller distances till it eventually settled in the centre.
edit: sorry, you said 'ignore friction'. If there were no losses then it would continue appearing alternately in Glossop and NZ forever.
It would basically act like a pendulum - and for broadly the same reasons - albeit in a straight line rather than through an arc?