Solar storms bring a dazzling yet safe spectacle: auroras
The Sun, nearing its peak of activity, is increasingly ejecting material that causes auroral spectacles in the sky. How do auroras form, and is there any danger hidden in this beauty?
In the past week, there have been particularly strong ejections of matter (so-called CMEs, or coronal mass ejections) of the highest class, X. Those directed towards us caused the strongest geomagnetic storm since 2003. Since April 9th, we have been observing exceptionally high auroral activity in the sky.
What causes the aurora borealis?
The Earth's protective system, the magnetic field, reacts in various ways to the stream of solar radiation reaching the Earth. It usually functions efficiently as an insulator, but this function can be disrupted during a geomagnetic storm. The plasma (mainly charged electrons, sometimes protons) previously ejected by the Sun is directed from space towards the Earth's polar regions.
An oval zone forms around the pole, where radiation excites oxygen and nitrogen molecules high above the surface, and they, returning to their natural state, emit multicoloured radiation, creating the auroras. The red is due to atomic oxygen and molecular nitrogen excited at about 200 km; green is the glow of molecular oxygen from 100 to 300 km. There are also blue auroras and pink when the radiation reaches less than 100 km and excites nitrogen to glow. Some colours, like yellow, are the result of mixing other colours.
Humans are constructed so that the beauty of natural processes, such as the auroras, makes them wonder if there is a hidden danger in this charm.
Should we be afraid of the aurora borealis?
The aurora itself has no impact on the functioning of our civilization because it is merely a beautiful light phenomenon. However, the radiation causing it, which Earth's magnetic field does not effectively block, can cause real damage. These are, however, mostly large-scale problems, especially for devices located high above the Earth's surface. At the same time, it should be noted that the impact of a geomagnetic storm concerns those aspects of human civilization that are related to electricity.
Therefore, during increased solar activity, there can be, for example, satellite failures in orbit, disruptions in the Earth's power network and communications, and even increased wear of structures such as pipelines. The consequences also affect radio transmissions (including GPS systems).
And what about the danger to the human body?
Regarding the strength of the geomagnetic storm, we do not have to worry about the direct negative impact of the aurora borealis on the body's function, as is the case with pigeons relying on biological compasses. The energetic radiation that still reaches Earth, even if it affects the operation of devices such as pacemakers, will not disrupt their function in a way that is dangerous to health. More damage may be caused by indirect effects, disruptions of navigation, and cell phone communications.
The impact on our well-being is a matter of more individual subconscious reactions, but even here, there is no direct correlation. However, science does not entirely rule out a connection between episodes of auroral occurrences and what happens in humans in the nervous and circulatory systems. However, this would be related to a radiation dose significantly smaller than we receive, for example, during an X-ray examination and even more invasive procedures like CT scans. Astronauts in space face a real danger from geomagnetic storms, hence there are warning systems to enable them to hide in well-insulated rooms. Usually, these are vehicles in which humans travel into space.
