Last weekend, it was possible to observe the northern lights at unusual latitudes, reaching as far as France, Germany, and the southern United States. Typically visible in polar regions, these lights lit up the skies even in the Île-de-France, offering a rare spectacle.
Northern lights on the night of May 10-11, 2024, in Strasbourg - Image Wikimedia
Northern lights, or "polar auroras," are phenomena caused by the interaction between charged particles from the solar wind and Earth's magnetosphere. When these particles strike Earth's atmosphere, they excite gas molecules, primarily oxygen and nitrogen, causing light emissions. The colors observed vary depending on the gases involved: green and red come from oxygen, while blue and purple result from nitrogen.
This rare spectacle in Europe and the United States was made possible by an intensification of solar activity. Massive solar flares, with coronal mass ejections, projected clouds of charged particles towards Earth. This intensification expanded the auroral oval, allowing the auroras to descend to lower latitudes.
Social media was abuzz with photos and videos of this spectacle, captured by amateurs and professional photographers. Favorable weather conditions, with clear skies and little light pollution, contributed to the visibility of the auroras.
If you missed this show, new opportunities should arise and it will be important to stay alert. Other chances to observe the northern lights in Europe and the United States are likely in the coming weeks and months. Solar activity follows a cycle of about 11 years, and we are currently approaching a solar maximum expected in 2025.