Northern lights are expected next night

The Northern Lights may be visible again next night. Two coronal mass ejections, that is, huge clouds of solar plasma, are on their way to Earth, but “we don’t know if it will be a direct impact or a blast razing,” said Sami Solanki, director of the German Max Planck Institute for Solar System Research, on Friday. One of the ejections is expected Saturday at dawn, the other Saturday evening, he added.

When coronal mass ejections reach Earth, they can generate geomagnetic storms. The American weather agency NOAA (National Oceanic and Atmospheric Administration) expects category G3 storms. The polar auroras visible across much of Switzerland in May were triggered by a storm of category G5, the highest.

Mr. Solanki specifies that even in the case of massive ejections propagating towards the Earth, we can only say in advance very imprecisely what their intensity will be or at what speed they will propagate.

We can only be more precise about half an hour before the plasma particles arrive on Earth, when satellites can measure them at a distance of about a million kilometers. Currently, the European Space Agency (ESA) is working on a probe that will continuously observe the Sun from a lateral position and should enable better predictions.