Sun Spotters

Federal scientists are on the lookout for an unpleasant solar surprise.

As if earthquakes, volcanic eruptions and the ever-present dangers of this year's hurricane season were not enough, government scientists and emergency planners are increasingly concerned about the need to predict and mitigate the impact of another force of nature: bursts of fury by our nurturing sun. With the sun coming out of one of its 11-year minimum cycles of activity, eruptions of solar flares, coronal mass ejection activity-discharges of plasma from the solar corona-and geomagnetic storms that disturb the Earth's upper atmosphere and the near-Earth space environment, all are expected to increase. These "space weather" events can severely damage electric power grids and oil and gas pipelines, as well as disturb the HF radio communications airlines use on polar routes and the navigation signals from Global Positioning System satellites. The Earth's vulnerability to space weather was demonstrated in March 1989, when a geomagnetic storm caused by a coronal mass ejection knocked out northeast Canada's Hydro-Québec power grid in 90 seconds, leaving millions of people without electricity for up to nine hours. A 2000 study by Thomas Teisberg and Rodney Weiher in the Journal of Policy Analysis and Management estimated that taking steps to avoid a similar outage would not only potentially save lives, but $20 billion worth of damage as well.

The job of ensuring we don't fall victim to a solar calamity rests with the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Boulder, Colo. The center keeps a constant watch on the sun's activity with the help of ground-based observers and NOAA, NASA and Defense Department satellites. It sends out forecasts and warnings as events dictate. Depending on the nature of a solar outburst, warning times can range from just a few minutes to days. The center uses computer models to enhance longer lead-time predictions of severe space weather conditions.

In February, the Space Weather Prediction Center hosted a two-day tabletop exercise simulating a solar storm similar to a 1921 event that disrupted telephone, telegraph and cable traffic in Europe and New York Central Railroad operations. Exercise participants included Craig Fugate, administrator of the Federal Emergency Management Agency; Helena Lindberg, director general of the Swedish Civil Contingencies Agency; and representatives from the European Commission, Energy Department and North American Electric Reliability Corporation.

In the first stages of the exercise, notes Thomas Bogdan, director of the Space Weather Prediction Center, radiation from a flare and a coronal mass ejection began disrupting radio signals and GPS devices. Later, it knocked out commercial satellites that transmit telephone conversations, television broadcasts and other data. Roughly a day later in the scenario, says Joseph Kunches, a scientist at the Space Weather Prediction Center, the coronal mass ejection caused "induced current in power grids to the extent that the grids were brought to their knees."

The scenario in the exercise "is not far-fetched," says Kunches. "There is a strong suggestion from historical evidence and even in 1989 with Hydro-Québec that a 100-year storm can cause a blow to critical infrastructure. So you could imagine how bad the consequences would be if there was a prolonged blackout that would deprive people of critical infrastructure and health and safety services-for example hospital services."

Scientists have some idea of how powerful such a storm could be. The 1859 Carrington Event, a series of solar magnetic storms, caused the failure of telegraph systems all over Europe and North America, and created auroras that were seen as far south as Hawaii and the Caribbean.

Could a future solar eruption be even more devastating? "There's no reason for us to think that the sun has only produced one Carrington event," says Kunches. "We've seen a small sample of what it can produce as we've been looking closely since World War II, and it begs the question of what an event of that magnitude can do." NASA has a program devoted to this question called Living With a Star. Its flagship spacecraft, the Solar Dynamics Observatory, launched in February, "will hopefully give us the data we need to figure out how bad these solar storms can be, and how often they occur," says program scientist Madhulika Guhathakurta.

So what happens if scientists find out a big solar event is imminent? Bogdan says prudence would dictate that power grid operators create temporary blackouts in their systems while the storm passes over, rather than risk losing their entire infrastructure for months or years.

A 2008 report by the American Meteorological Society also concludes that with timely and accurate forecasts, "airlines may reroute flights to avoid high radiation levels and communications blackout areas; spacecraft operators may put satellites in safe mode or reschedule critical maneuvers; and survey and drilling companies reliant on precise GPS measurements may cease or delay operations."

Given the importance of early warnings, Bogdan says it's vital to maintain continuity of observations from satellites such as NASA's Advanced Composition Explorer, which has operated since 1997. A potential backup for ACE is the Deep Space Climate Observatory, also slated to observe space weather as well as aspects of climate change on Earth following a scheduled launch in late 2013. The program began its life as Vice President Al Gore's concept for a satellite providing a near-continuous view of the entire Earth. The association with Gore made the satellite, even with a revised science mission, a low priority for the Bush administration.

As we move into a peak solar activity period, Paul Kintner, a science fellow at the State Department and a professor of electrical and computer engineering at Cornell University, says it's critical to make users of technological systems aware of what a major solar storm can do so they can plan accordingly. "It's somewhat like saying several years ago that it's possible a hurricane can strike New Orleans," he says. "The probability was low. The probability of an individual flare or solar outburst hitting Earth is also low, but there will be enough of them that it will eventually happen."

Edward Goldstein was lead writer at NASA from 2002 to 2009.