On September 4, the sun started sputtering. A moderately large flare (classified as an M5.5) erupted at approximately 18:30 UTC. It produced a coronal mass ejection aimed at Earth. The sun continued to flare on September 5. A solar energetic particle event from the previous day’s activity arrived at the Earth, where it likely affected radio communications as well as the health of satellite systems. On September 6, the sun produced two massive X-class flares. This is the category for the strongest of all solar flares.
NASA announced one was the most powerful since at least 2008. It produced another coronal mass ejection. Over the next day, the same sunspots continued to spit out more solar flares. It took about an hour for the solar energetic particles they emitted to arrive at Earth. These protons are incredibly fast-moving. They can affect communication systems, typically in the polar regions where they are more likely to enter into the Earth’s atmosphere. As with all increases of radiation in space, they can also affect satellite systems and the health of astronauts.
Early in the morning hours of September 7 in the U.S., that first coronal mass ejection that erupted from the sun three days earlier arrived at Earth. Because of the way its magnetic field aligned with Earth’s, it generated only a small geomagnetic storm. There has likely been a loss of global navigation system satellite communications in those same areas, but it will take time for the data to be analyzed and for us to gain a full understanding of how this space weather activity has affected those on the ground. The radiation storms may also force flights over the polar regions to reroute to avoid increased radiation exposures for people on board and potential loss of communication and navigation systems for aircraft on these paths.
We don’t need to worry about this coronal mass ejection being “the big one” – a solar storm direct hit that could cause widespread power blackouts and trigger as much as US$2 trillion worth of damage, according to a National Academy of Sciences study.
To see how these events may affect Earth, please visit NOAA’s Space Weather Prediction Center at http://spaceweather.gov