In 2023, during the early hours of November 6, the population of the Cáceres region, in Extremadura, witnessed a unique spectacle. The night sky was dyed red with flashes, they were northern lights. This phenomenon, more common in the polar areas, was present in an unusual way in this region. It also spread even to other parts of Central Europe, such as some regions of Italy, France, Slovakia, Ireland and Poland.
What are the northern lights?
The northern lights, also known as the northern lights, are natural phenomena. Bright, colorful lights occur in the night sky near the polar regions. They form when charged particles from the solar wind collide with the Earth's atmosphere. In turn, they interact with gases in the ionosphere, such as oxygen and nitrogen.
They are most common in regions close to the Arctic Circle, such as Alaska, Canada, Norway, Sweden, Finland, Iceland and Russia. They can occasionally be seen at lower latitudes during periods of intense solar activity.
In the southern hemisphere, they are called auroras australis and are visible in regions close to the Antarctic Circle. It can be seen in Antarctica, Australia, New Zealand and some parts of South America, such as Patagonia in Argentina and Chile.
Why did the northern lights appear in central Europe?
Solar or geomagnetic storms are the cause of their appearance. The Sun, located 150 million kilometers away from Earth, constantly emits charged particles called ions and forms the solar wind.
These particles, propelled by the solar magnetic field, take only a few days to reach our planet. As they approach Earth, they interact with the Earth's magnetic field. Likewise, they head towards the poles, where the atmosphere is full of oxygen and nitrogen molecules.
When solar particles interact with these molecules, they excite them, generating bright colors in the sky. After brief moments, the molecules quickly return to their ground state, releasing energy in the form of photons, which are the particles that produce light. They are usually observed in the polar regions of the Earth due to the attraction of the Earth's magnetic field, which directs the solar wind towards the poles.
Why did they appear in Spain?
The question that arises is why these impressive lights traveled so far from their usual location. Is this something normal or should we worry about it? Their appearance in regions so far from their “natural habitat” undoubtedly attracts attention and raises questions about changes in climate and the environment.
The cause that generated them is an intense solar storm. This phenomenon is due to magnetic reconnection in the Sun, releasing more particles and plasma than usual. The resulting solar wind interacts with the Earth's magnetic field. It diverts the particles to other areas of the atmosphere and causes the northern lights in places far from the poles.
Although it may seem worrying, these geomagnetic storms are normal and are associated with the solar cycle, which repeats every 10-12 years. Currently, we are in a period of solar maximum, with a peak expected in 2025, which means it is common to experience strong solar winds. These types of phenomena are expected to continue occurring over the next two years as the solar cycle comes to an end.