WASHINGTON (Reuters) - A strong geomagnetic storm is racing from the Sun toward Earth, and its expected arrival on Thursday could affect power grids, airplane routes and space-based satellite navigation systems, U.S. space weather experts said.
The storm, a big cloud of charged particles flung from the Sun at about 4.5 million miles per hour (7.2 million km per hour), was spawned by a pair of solar flares, scientists said.
This is probably the strongest such event in nearly six years, and is likely more intense than a similar storm in late January, said Joseph Kunches, a space weather specialist at the U.S. National Oceanic and Atmospheric Administration (NOAA).
This solar disturbance is a three-stage affair, or as Kunches said in a telephone interview from Boulder, Colorado: "We hit the trifecta."
These are the stages he described, with the first two already affecting Earth: