ETH team achieves milestone in solar physics

(CONNECT) Researchers led by ETH Zurich have been able to track a particularly active region on the sun during three solar revolutions for the first time, according to a statement from their university. Because the sun revolves around itself once in about 28 days, such a region rotates out of the Earth's field of vision after two weeks and remains hidden for two weeks.

But the international team led by Ioannis Kontogiannis, solar physicist at ETH Zurich and the Istituto ricerche solari Aldo e Cele Daccò in Locarno, and Louise Harra, ETH professor and director of the Physico-Meteorological Observatory Davos, combined the data from two space probes, the European Space Agency's Solar Orbiter and NASA's Solar Dynamics Observatory. This enabled it to extend the observation period from two weeks to 94 days. The ESA probe will fly once around the sun in around six months and will also observe its rear side, while the NASA probe will record activities on the front side.

This allowed the group to see how the strongest solar storm of the past 20 years in the solar region NOAA 13664 formed on April 16, 2024 on the back side of the sun, changed and disintegrated on July 18, 2024. "This is the longest continuous series of images ever created for a single active region - a milestone in solar physics," says Kontogiannis.

When NOAA 13664 was on the Earth-facing side in May 2024, it not only caused auroras that could even be seen in Switzerland, but also massive disruptions on Earth, for example in digital agriculture. The increased radiation is also dangerous for satellites. In February 2022, the American aerospace company SpaceX lost 38 of its 49 Starlink satellites.

According to the ETH, the observations that have now been made should contribute to a better understanding of solar storms and their possible effects on the Earth. The aim is to forecast space weather more accurately so that modern technology can be better protected. ce/mm