By Dr David Whitehouse
BBC News Online science editor
The Earth has been buffeted by a cloud of superhot gas thrown off the Sun a few days ago. Scientists report it caused a moderate "geomagnetic storm".
One big sunspot and another on the way
Charged particles affected electric utilities, airline communications and satellite navigation systems.
"We predicted it would be a mid-level storm, and that's where it is," said Joe Kunches, chief of space weather operations at the National Oceanic and Atmospheric Administration's Space Environment Center in Boulder, Colorado.
Power grid operators and satellite users were notified about the storm and no serious problems have been reported.
"We've heard from the power grid operators. They're doing OK, but they're seeing the effects of the storm in their data," Kunches said.
Communications systems in northern Canada are reported to have also seen some effects of the storm.
Disruptions to electrical systems are caused by wild fluctuations in the Earth's magnetic field.
"The Earth's magnetic field pulls it in... and is now trying to balance it," Kunches said.
The Global Positioning System - a satellite navigation facility - was affected, losing its high precision service for a while.
The storm struck on Friday and disrupted the Earth's magnetic field
High frequency airline communications were also degraded in some cases.
Climbers on Mount Everest also reported interference on their radio equipment.
Two major expeditions on the mountain have reported trouble sending data via satellite.
As the storm continues, predicted to be followed by others for the next two weeks or so, further disruption is predicted for satellites, power systems and even mobile phones.
It comes from one of the largest groups of sunspots seen for years.