The largest solar flare in years is hurdling towards Earth at 4 million mph and is expected to hit early Thursday morning.
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 Thursday and could disrupt utility grids, airline flights, satellite networks and GPS services, especially in northern areas. But the same blast also could paint colorful auroras farther from the poles than normal.
Scientists say the storm, which started with a massive solar flare early in the week, is growing as it races outward from the sun, expanding like a giant soap bubble. When it strikes early Thursday, the particles will be moving at 4 million mph (6.4 million kph).
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 do not 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 also are at risk, said Jeffrey Hughes, director of the Center for Integrated Space Weather Modeling at Boston University.