According to data from the US Atmosphere Agency NOAA, the number of sunspots is currently higher than it has been in over 20 years. Since the frequency of sunspots is related to solar activity, there are also many solar storms - and depending on the direction, they can also be explosive for the earth. There will probably be more solar storms in the next few years, said Sami Solanki, director at the Max Planck Institute for Solar System Research (MPS), the German Press Agency.
Sunspots occur more frequently in an approximately eleven-year cycle. The sun is currently in solar cycle 25 and according to data from NOAA, the number of sunspots has already exceeded the maximum of the previous one. "However, it must also be emphasized that cycle 24 was an extremely weak cycle," said Solanki. The number of sunspots across all solar cycles is currently in a medium range.
According to Solanki, a higher number of sunspots is a sign that the sun's magnetic field is stronger and that the sun itself is more active. There will then be more mass ejections, in which part of the sun's atmosphere is simply thrown out into interplanetary space, the researcher said.
This is how sunspots are formed
The German Aerospace Center (DLR) explains the formation of sunspots as follows: hot matter from the interior of the sun is constantly swirling to the surface. This process can be hampered by local intensifications of the sun's magnetic field. The result: Somewhat colder spots appear on the sun's surface, which become visible as sunspots.
"A sunspot consists of a very strong magnetic field. That's several thousand times stronger than the Earth's magnetic field," Solanki explained. "This means that much less energy comes to the surface there and much less can be emitted. And that's why the spots appear dark."
From auroras to satellite damage
The more sunspots experts discover, the more likely solar flares are. According to the European space agency Esa, high-energy particles with a dimension of several tens of billions of tons can be thrown into space. They can also reach Earth, some 150 million kilometers away, within hours. The earth's protective shield, the magnetosphere, "is pulled apart like a soap bubble and can tear, so to speak". The particles can then enter the magnetic field.
This can lead to "beautiful things like auroras," but also satellite damage, Solanki said. The collapse of a power grid is also possible. "It's happened before, mostly at higher latitudes. But we haven't had a really big solar storm in the last 150 years. It can get even worse," emphasized the researcher. Really big eruptions are rare. Even with a few spots, however, "just a single huge spot" on the sun is enough, which with great magnetic energy could also cause a more dangerous eruption.
fluctuations in the brightness of the sun
However, the influence of solar storms on the Earth's climate is small: "The brightness of the sun varies with the number of sunspots, and there are various indications that such fluctuations have a minor influence on the climate," said Solanki. "However, it is important to emphasize that such fluctuations in brightness have not made a significant contribution to the rapid rise in global temperature on Earth over the past 50 years or so."
In order to improve the forecast for the so-called space weather in the future, the European space agency is currently working on a satellite which, according to Solanki, should be launched in a few years. It is designed to measure the sun's magnetic field.
