Solar Magnetic Storms

Planetary defense is usually seen as protecting Earth from asteroid or comet impacts.  Another threat, however, comes from solar magnetic storms.

Such events throw out huge pulses of energy from the Sun.  A direct hit on Earth by a massive solar magnetic storm could knock out satellites, communications networks, and energy infrastructure.  Recovering from such a disaster could take years, and could, therefore, result in the collapse of the civilization we know.  It's another threat planetary defense must counter.