The solar storm that struck Earth's magnetic field early Thursday morning is not as strong as scientists feared, a U.S. physicist said.

"All told, it's not a terribly strong event," said physicist Joe Kunches of the National Oceanic and Atmospheric Administration at a news conference Thursday.

The solar outburst struck Earth's magnetic field around 6:05 a.m EDT (1105 GMT), Kunches said, cutting some radio communications at the poles, but it didn't upset electronics and communications elsewhere. However, there were still some communication disruptions in the polar regions of the Earth that led airlines to reroute flights on Wednesday to avoid problems.

Like hurricanes, solar storms have a rating system, with G1 being less severe and G5 being more intense. Scientists initially expected a G3 storm, but on Thursday said it turned out to be a "minor" G1 disturbance.

Kunches said NOAA may have overestimated the effects of the blast, but "it could get worse," if the storm's magnetic field shifts in a way that delivers a stronger pop to Earth's protective magnetic field.

The sun operates on an 11-year cycle of waxing and waning solar outbursts, expected to increase over the next 12 to 19 months.

VietNamNet/Xinhuanet