Scientists have detected another big eruption on the sun, blasting hot, electrically-charged gases our way. It is expected to cause a second geomagnetic storm Friday, threatening Earth's electrical systems. The quick succession of such massive solar events is unusual.
The U.S. space agency, NASA, says U.S. satellites observed another huge explosion on the sun Wednesday, generating another fast-moving cloud of electrically-charged gas expected to reach Earth on Friday. The blast, called a solar flare, followed by just a day, one of the largest flares ever observed.
An earlier one erupted last week, but scientists say the particle cloud from it largely missed our planet.
Of the two latest outbursts, Solar scientist John Kohl of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, says it is as if Earth is on the wrong end of a double-barreled solar shotgun.
"Having two of the very largest ones we have ever seen, and then having them come off within a day of one another, and positioned perfectly to send material toward the Earth, I think is unprecedented in anyone's recollection," he explained.
Such gigantic clouds are made up of charged atomic particles called protons and are many times larger than Earth. They interact with our planet's magnetic field and can induce damaging surges of voltage in electric systems, like power grids, satellites, high frequency radio communications and television.
The only reported effects from the first big solar blast this week could be the loss of communications with two Japanese satellites, although Japanese space agency officials cannot officially link them with the damage. At the same time, high-frequency radio contact was interrupted on some airlines flying far northern routes, where the electrical effects are strongest. Power companies have reduced line loads to allow leeway for possible surges.
But, according to John Kohl, the second round of solar gas is like a freight train that crashes into a slower moving train just leaving the station. "What will happen is that material will catch up with the slowest material that is still left over from the original event, and we'll see the combination of the two," he said.
Mr. Kohl emphasizes that the combined effects cannot be predicted.
The Harvard-Smithsonian Center for Astrophysics says people on the ground and in airlines are safe because Earth's atmosphere provides a shield against the solar radiation. Because the international space station is above the atmosphere, astronaut Michael Foale and cosmonaut Alexander Kaleri briefly retreated to a shielded Russian module for a few orbits Wednesday, and might do so again during the second surge of solar particles.