New Model Predicts Severe Solar Activity

Tuesday, March 7, 2006

Sun-spawned cosmic storms that can play havoc with earthly power grids and orbiting satellites could be 50 percent stronger in the next 11-year solar cycle than in the last one, scientists said yesterday.

Using a new model that takes into account the sun's subsurface activity and data about previous solar cycles, astronomers offered a long-range forecast for solar activity that could start as soon as this year or as late as 2008.

They offered no specific predictions of solar storms, but they hope to issue early warnings that will give power companies, satellite operators, and others on and around Earth a few days to prepare.

"This prediction of an active solar cycle suggests we're potentially looking at more communications disruptions, more satellite failures, possible disruptions of electrical grids and blackouts, more dangerous conditions for astronauts," said Richard Behnke of the Upper Atmosphere Research Section at the National Science Foundation.

The prediction, roughly analogous to the early prediction of a severe hurricane season on Earth, involves the number of sunspots on the solar surface, phenomena that have been monitored for more than a century.

Every 11 years or so, the sun goes through an active period, with lots of sunspots.

The sun is in a relatively quiet period but is expected to get more active soon, scientists said. There is disagreement, however, as to whether the active period will start within months -- late 2006 or early 2007 -- or years, with the first signs in late 2007 or early 2008.

Whenever that period begins, the new forecasting method shows, sunspot activity is likely to be 30 to 50 percent stronger than in the last active period.

The strongest solar cycle in recent memory occurred in the late 1950s, when there were few satellites aloft and no astronauts in orbit, and there was less reliance on electrical power grids .

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