When the Sun sneezes

The most powerful solar flare in years last week served as a reminder of the dangers of solar storms to a society increasingly dependent on electronics and communications.  

When the Sun's atmosphere explodes, it can have explosive consequences on Earth. The X-rays and UV radiation released by these solar flares are capable of interfering with everything from radio communication to our whole electrical grid. If that sounds a little scary, well, it should. That's why scientists held a session at AAAS 2011 to talk about space weather and how Earthlings can prepare for the damage it could cause. Jeff Foust of The Space Review was there. In an article for that website he explains why space weather is so dangerous to human civilization, what scientists are doing to improve space weather forecasts, and how freaked out we all really ought to be.

As the Sun goes through another peak in activity over the next few years, increasing the number and severity of solar storms, it raises the question of just how prepared we are for disruptions that could result from such storms. The conference session indicated that such planning is, in many cases, quite limited.

One particularly significant vulnerability is the growing reliance on satellite navigation systems like GPS, whose signals are used by a wide variety of industries for highly accurate timing data. A solar flare, though, would ionize the upper atmosphere and thus affect propagation of GPS signals through it, increasing errors or even causing outages. How are companies that rely on GPS prepared to react to its interruption in the event of a solar storm?

Stephan Lechner of the Institute for the Protection of the Citizen, a European Commission Joint Research Centre, discussed one industry in particular, telecommunications, that uses GPS for time synchronization. "Unfortunately, there's no simple answer," he said of an analysis of the industry's vulnerability. Many GPS receivers used by telco companies, he said, simply assume GPS signals will always be there.

o