Earth has a giant invisible magnet running through it. The spot a compass points to - magnetic north - is not the same as the North Pole on a map, and it does not sit still. It is constantly drifting.

For most of recorded history it wandered slowly around northern Canada. But since the 1990s it has sped up dramatically and is now racing across the top of the world toward Siberia. On top of that, Earth's whole magnetic field is slowly getting weaker - and a weaker field lets more of the Sun's energy reach us. Open the 3D Earth tab to watch the pole's real path.

The Sun throws off bursts of radiation (solar flares) and clouds of charged particles (solar storms / CMEs). When those reach Earth they crash into our magnetic field. Most days it just paints pretty auroras near the poles - but a big storm can knock out GPS, radio, satellites and even power grids.

A severe solar storm is one of the few natural events that could take down the electric grid over a whole continent at once. The good news: it gives warning - flares are seen instantly, the storm clouds behind them take 1-3 days to arrive. Watching the numbers here gives you a head start.