Two minor solar storms expected to strike Earth

Mass ejections could affect satellites, radio transmissions late Friday, midday Saturday

Two solar storms forecast to strike Earth overnight may degrade global position satellite devices and radio transmissions.

The first and smaller of the two coronal mass ejections will arrive later Friday, Thomas Berger, director of the U.S. Space Weather Prediction Center, said in a conference call with reporters. The second one should hit by midday.

“Current forecasting of these events is tricky, so we cannot forecast down to the hour,” Berger said.

Although neither ejection would be considered a major event, scientists are watching closely because they came so close together from the same area, Berger said. Besides the expected effects on GPS data and radio transmissions, they may create an aurora display across the Northern U.S. The geomagnetic storms touched off by the solar action will be strongest going into the weekend, Berger said. The storms will be G2 or G3 on the centre’s five-step scale for geomagnetic events, with G5 being the strongest.

The coronal ejections both erupted out of a sunspot complex that also produced two flares this week, Berger said. The spots are big magnetic storms on the sun that darken its surface and can be seen from Earth. “Essentially the sun just shot out a magnet and it is about to interact with another magnet, Earth’s magnet,” said William Murtagh, program co-ordinator at the centre in Boulder, Colo. Large solar events can prompt aircraft to divert from polar routes because of increased radiation, although that isn’t expected to happen this time. In addition to measuring geomagnetic storms, the space weather centre classifies radiation effects of solar events on a similar five-step scale. The current radiation impacts are rated at S1. An S3 or higher is needed to divert airline traffic, Murtagh said. Berger said U.S. electric power grid operators should be able to handle these events. There isn’t a concern for electronics on the ground. The storms won’t match the power of a storm recorded in1859 by British astronomer Richard Carrington, now known as the Carrington Event. It electrified telegraph lines, shocking operators and created an aurora seen as far south as Cuba and Hawaii, according to the National Aeronautics and Space Administration website. Another large storm in 2012 missed Earth, Berger said. Both the Carrington Event and the 2012 storm took about 17 hours to travel from the sun to the earth, Berger said. These two eruptions are taking 40 to 50 hours. The second eruption is more powerful and is catching up to the first, Berger said.