A geomagnetic storm from a solar flare that erupted on the sun's surface earlier this week will likely collide with Earth this weekend, scientists say.
The coronal mass ejection on Thursday, caused by the release of excess solar energy, is classified as an X1.4 event. That means the storm is probably too weak to affect satellites used for cell phone communication, but communication using shorter wavelengths, such as radio, may be affected, said John Raymond, a physicist at the Harvard-Smithsonian Center for Astrophysics.
"Imagine something with the mass of a mountain being ejected at a speed of a million miles an hour," Raymond said, adding that by the time the storm reaches Earth, its energy will have been spread out over an enormous area. Scientists expect the storm to arrive Saturday morning, and it is still possible that it will miss Earth.
The effects on communications may not be disruptive, Raymond said. During a recent coronal mass ejection, radio operators suddenly found their reach had extend to new continents. Such storms were first noticed in the 1800s, he said, when telegraph operators found they could send telegraphs without batteries.
On rare occasions, storms 20 times more powerful than the one currently approaching have been known to cause electric surges that shut down entire power grids, Raymond said. The surges are the result of movement in the lines of Earth's magnetic field.
The most notable effect of the coming storm is likely to be the spectacular auroras it produces in the night sky, Raymond said.
In March, the largest solar flare in five years hit Earth, prompting fears of disruptions to flights, GPS systems and power grids, but those problems never materialized.