Large solar storm racing toward Earth

? Earth’s magnetic field is about to be shaken like a snow globe by the largest solar storm in five years.

After hurtling through space for a day and a half, a massive cloud of charged particles is due to arrive early today and could disrupt utility grids, airline flights, satellite networks and GPS services, especially in northern areas. But the same blast could also paint colorful auroras farther from the poles than normal.

Scientists say the storm, which started with a massive solar flare earlier in the week, is growing as it races outward from the sun, expanding like a giant soap bubble. When it strikes early today, the particles will be moving at 4 million mph.

“It’s hitting us right in the nose,” said Joe Kunches, a scientist for the National Oceanic and Atmospheric Administration in Boulder, Colo.

Astronomers say the sun has been relatively quiet for some time. And this storm, while strong, may seem fiercer because Earth has been lulled by several years of weak solar activity.

The storm is part of the sun’s normal 11-year cycle, which is supposed to reach peak storminess next year. Solar storms don’t harm people, but they do disrupt technology. And during the last peak around 2002, experts learned that GPS was vulnerable to solar outbursts.

Because new technology has flourished since then, scientists could discover that some new systems are also at risk, said Jeffrey Hughes, director of the Center for Integrated Space Weather Modeling at Boston University.

A decade ago, this type of solar storm happened a couple of times a year, Hughes said.

The sun erupted Tuesday evening, and the most noticeable effects were to have arrived here between midnight and 4 a.m. today, according to forecasters at the space weather center. The effects could linger through Friday morning.