Sunrise-III provides new insights into solar magnetic fields
In 2024 the balloon-borne observatory Sunrise-III floated into Earth's stratosphere and pointed its instruments toward the Sun. An international team led by the National Astronomical Observatory of Japan observed regions classified as quiet solar surface.
The measurements revealed that even in these apparently calm areas the magnetic field is far more structured than previously thought. Small, interconnected features formed a fine network that had only been expected in active solar regions.
Researchers suggest that these subtle magnetic fields could influence the energy flow from the solar interior to the surface. Further analysis of the data aims to clarify how such structures modulate overall solar activity and potentially affect space weather.
To gather the data, Sunrise-III flew for several hours at an altitude of about 35 kilometers, where atmospheric scattering is minimal. The observatory carried a spectropolarimeter capable of measuring the polarization of sunlight with high precision, allowing magnetic fields in the photosphere and chromosphere to be visualized.
The findings have been published in a scientific journal and highlight the value of stratospheric observations for solar physics. They demonstrate that relatively low‑cost balloon missions can deliver details that ground‑based telescopes struggle to obtain because of atmospheric disturbance and daylight limits.