When Our Magnetic Field Flips. By Rick Groleau; Posted 11.18.03; NOVA; Every so often—every 250,000 years on average—the Earth's magnetic poles reverse polarity.

When an electric current passes through a metal wire, a magnetic field forms around that wire (see diagram at right). Likewise, a wire passing through a magnetic field creates an electric current ...

As we approach solar maximum, something strange is happening to the sun's magnetic field. We explore this flip in polarity in more detail and look at the effects it could have on Earth.

The small magnetic field caused by the current in each coil add together to make a stronger overall magnetic field. Figure caption, A solenoid, shown here in cross section, ...