Concerns flare anew about solar activity

(Associated Press) — Scientists again warned that communications on Earth could be disrupted this week by another spectacular eruption on the surface of the sun and that it might even hamper firefighting efforts in California.

"It's headed straight for us like a freight train," said John Kohl, a solar astrophysicist at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "This is the real thing."

Predictions are it could strike Earth's magnetic field by midday today.

The explosion of gas and charged particles into space from the corona, the outermost layer of the sun's atmosphere, isn't harmful to people. But it can knock out satellite communications, which some emergency crews are relying on in battling California's wildfires.

Similar solar events in recent years have disrupted television transmissions, GPS navigation, oil pipeline controls and even the flow of electricity along power lines.

Space weather forecasters first warned of that possibility last week, when a previous solar flare erupted, and then they saw a new sunspot region developing in another region of the sun's face.

The cloud of charged particles from last week's eruption struck Earth "with only a glancing blow," Kohl said. It disrupted some airline communications.

But Kohl said scientists observed the biggest such explosion in 30 years shortly before 6 a.m. EST Tuesday. It produced a particle cloud 13 times larger than Earth and hurtled through the solar system at more than 1 million miles per hour.

The resulting geomagnetic storm could be ranked among the most powerful of its kind and last for 24 hours.