Perhaps, if you have traveled to the northern or southern parts of the planet, you have had the opportunity to admire the northern and southern auroras, respectively. They represent the light emitted by particles in the upper atmosphere upon their interaction with energized ones in the magnetosphere. But seeing them at much lower latitudes means something is wrong with the Sun, and a geomagnetic storm is hitting the Earth.
What is happening to the Sun?
In some religious beliefs, the northern lights are considered to be ancestral spirits who remain to communicate with us from the sky. For scientists, instead, they are a much more complex phenomenon of mixing ionospheric dynamics, a manifestation of the close connection between the Earth and the Sun. And for industrial activity they are a risk factor.
In February 2022, SpaceX, the company controlled by Elon Musk, launched 49 satellites of the Starlink internet network into low Earth orbit (LEO). It was the 36th launch of such satellites, and everyone assumed that everything would go like the previous 35.
But on the very day of launch, a huge coronal solar mass ejection hit the planet, writes sciencealert.com. It caused a geomagnetic storm in the atmosphere at an altitude between 100 and 500 kilometers, the very intended target of the Starlink satellites.
The phenomenon threw a huge amount of electromagnetic energy directly into the Earth’s upper atmosphere. It produced beautiful auroras, but it also increased air density.
Higher density is not normally a concern for low-orbit satellites, as they typically operate at altitudes of less than 400 kilometers.
What is the risk for the Earth, the experts warn
However, the Starlink satellites were originally programmed to reach an altitude of 210 kilometers. It is much closer to Earth and the air density is exponentially higher. 38 of the 49 satellites initially launched were lost to the dense atmosphere, being pulled back towards the planet.
At the present time, we are at the beginning of the period of solar maximum which will last until 2026. The solar cycle is a periodic variation in solar radiation, with an average duration of 11.2 years, variation that causes climatic changes on Earth.
The current solar cycle is the 25th since 1755, the year in which the recording of astronomical observations on sunspots began.
From 2023 to 2026 will be the period known as solar maximum, and the peak will be in 2025. Solar maximum is contrasted with solar minimum, when there are no sunspots. The 25th solar cycle will end in 2030.
In the previous solar cycle, which ended in 2019, there were 927 solar storms classified as moderate or weak – an average of one every five days. But in the current cycle, although the peak of solar activity is expected in 2025, we are already seeing an unusual intensification of it.
This means, experts say, that we should expect even more geomagnetic storms, more auroras at lower latitudes than usual, and riskier conditions for operating LEO satellites.
Geomagnetic storms can cause many problems, but their effects are usually less obvious than setting a satellite on fire in the atmosphere. But they can cause radio signals to drop, as happened in areas of North America on August 7.
Even minor storms can damage radio signals used by civilian and military maritime and aviation systems. Strong ones can cause radio transmissions to drop for hours around the globe. In addition, they can also cause failures of electrical systems, as happened in 1989 at the hydroelectric plant in Quebec, Canada.
Nowadays, with the help of ground-based radars and magnetometers on satellites, we can estimate the “weather” in terms of electromagnetic storms, but we must never forget the incredible power of the Sun in whose light we live.
