An X1.6 class solar flare flashes in the middle of the sun in an image taken Sept. 10, 2014, by NASA's Solar Dynamics Observatory.NASA/Reuters
Global positioning systems and radio transmissions may be degraded through Saturday as two solar eruptions strike Earth and affect its magnetic field.
The U.S. Space Weather Prediction Center is tracking two two coronal mass ejections, "huge expulsions of magnetic field and plasma" that shot out of an area near the center of the sun's disc.
"Essentially the sun just shot out a magnet and it is about to interact with another magnet, Earth's magnet," William Murtagh, program co-ordinator of the U.S. Space Weather Prediction Center, said yesterday. When the ejections reach Earth, they will touch off geomagnetic storms that are forecast to last at least until tomorrow.
The first wave of the two-part event arrived Thursday night and is forecast to touch off a G2 storm. The second one will arrive about midday Friday Eastern time and with the combined effects of the first one may create a G3 incident. Geomagnetic storms, like hurricanes, are classified on a five-step scale with G1 being the weakest and G5 the strongest.
Earth should be spared the most crippling impacts of these kinds of events, which can include disruptions to electric grids and radiation strong enough to cause polar flights to change routes, said Thomas Berger, the centre's director. People away from city lights may see a brilliant display in the northern sky.
What worries scientists, electric grid operators, and just about anyone else who thinks about these things is that they can get big and cause severe problems. In March, 1989, all of Quebec lost power because of a solar storm, according to the National Aeronautics and Space Administration website. The New York power grid lost 150 megawatts and New England dropped 1,410 megawatts.
Geomagnetic storms caused failures in 1958 and in 2003 as well, the centre said on its website. The strongest such storm on record occurred in 1859, electrifying telegraph lines, shocking operators and starting fires in papers on their desks, NASA's website shows.
It also produced an aurora that was seen as far south as Cuba and Hawaii. The flare is named the Carrington Event after British astronomer Richard Carrington, who saw it from his observatory in England. In 2012, material from an eruption of similar size missed Earth.
Berger said Friday's event won't rise to that scale. Both the Carrington flare and the 2012 flare took about 17 hours to travel from the sun to Earth, which is an indication of their power. The two now arriving took more than 40 hours.
Aside from a little static, the thing many people might notice is the glow of the aurora in the northern sky, which should be seen in the states bordering Canada and possibly farther south. To see it well, Murtagh said, people will have to travel away from the city lights and be under clear skies.