A massive coronal hole in the sun’s atmosphere, shaped like a butterfly, could affect Earth in the coming days. Space weather experts are predicting geomagnetic storms and spectacular auroras on September 13-14.
This coronal hole is about 500,000 kilometers wide; it is sending streams of fast-moving solar wind towards Earth. These streams are expected to reach us on September 14. The UK Met Office is predicting activity ranging from a G1 (weak) storm, but a G2 (moderate) storm is also possible.
