Question: Why do you think the Earths magnetic field flips?

Iain Bethune answered on 24 Jun 2015:

This phenomenon is called Geomagnetic Reversal, and is quite common – the most recent one was 41,000 years ago. The reason for it is that the magnetic field is caused by the convection (flow of material) in the Earth’s iron core – this drives electric currents that cause a magnetic field. The dynamics of the core mean that sometimes this can cause the magnetic field to flip over – but it is very unpredictable, so we don’t know whether the next reversal will be in 10 year or 100,000 years from now!