Earth could be in for a shock, so to speak, if it is hit with a really major geomagnetic storm: The Biggest Threat to the Global Economy Could Come From Outer Space: If the sun sneezes, the economy will shatter – Niraj Chokshi/The Atlantic.

Keep an eye on the sun with a daily peek at the HobbySpace Sun and Space Weather page.  Holds lots of real time images of the sun and data displays from solar monitoring satellites.