Earth Hour starts at 8:30 PM tomorrow. Yet as people around the world prepare to throw the switch to enlighten others about climate change, I’m mildly freaked about the prospect of the lights going out for good. New Scientist reports that NASA and the National Academies of Science are pretty concerned about giant solar plasma balls wiping out the world’s power grids in an instant. And not just for an hour or two; we’re talking months or years—or at least until someone figures out a way to make more electrical transformers without using electricity. (Read the full report here.) Such a “space weather Katrina,” as the NAS helpfully describes it, could literally be the beginning of a new dark age. Oh, and of course, the next round of solar flare-ups is scheduled to start in—when else?— 2012.Is the risk of a severe geomagnetic storm just more apocalyptic hype? New Scientist‘s doomsday scenario certainly is sensational, and some of its commenters accuse NASA of trying to scare us into increasing its funding. But the NAS report puts it calmly, “While a severe storm is a low-frequency-of-occurrence event, it has the potential for long-duration catastrophic impacts to the power grid and its users.” The map on the right shows regional susceptibility to storm-induced blackouts; the higher the percentage, the higher the risk that they’d “experience long-duration outages that could extend multiple years.” Considering that, more research into space weather seems like a relatively cheap fix, especially if it could increase the warning time for a plasma event. Right now, we’d be lucky to get about 15 minutes advance warning; barely enough time for utilities to protect their facilities by shutting them down. Add some more time to that window and perhaps ensure that the Smart Grid has a built-in kill switch, and maybe we can go back to worrying about pole reversal.