Scientists have uncovered a surprisingly complex network of magnetic structures hidden above regions of the Sun that appear relatively calm. Using the Sunrise-III solar observatory, which traveled high into Earth's stratosphere aboard a balloon in 2024, an international research team led by the National Astronomical Observatory of Japan (NAOJ) discovered intricate, thread-like magnetic features that had previously been difficult to observe. The findings reveal that even the Sun's seemingly quiet regions contain elaborate magnetic structures.
They also offer new clues to how energy travels upward through the solar atmosphere and contributes to its heating. A Hidden Web of Magnetic Threads Above the Sun Sunrise-III detected numerous thin, elongated magnetic structures woven into a larger network of magnetic fields above a quiet region of the Sun. This network, known as the magnetic canopy, extends through the chromosphere, a layer of the solar atmosphere located above the Sun's visible surface.
The canopy develops as magnetic fields concentrated at the solar surface (photosphere) spread outward and arch upward into the chromosphere (chromosphere). Rather than forming a relatively smooth, uniformly expanding structure, however, the new observations reveal that the canopy contains many narrow, thread-like features. To investigate how these structures form, researchers used computer simulations that successfully reproduced the patterns recorded by Sunrise-III.
The results suggest that movements on the solar surface twist magnetic field lines, creating the intricate structures observed higher in the atmosphere. The observatory also examined another quiet region near the solar limb (visible edge of the Sun). There, it measured magnetic fields within spicules, narrow jets of solar material that extend upward from the surface.
These observations revealed how the distribution of magnetic fields changes with increasing height above the Sun's visible edge. Why the Sun's Quiet Regions Are Difficult to Study Although the Sun is constantly active, much of its surface lacks prominent features such as sunspots. Scientists describe these comparatively inactive areas as "quiet." They cover most of the Sun, making them especially important for understanding how our star behaves.
However, quiet does not mean magnetically inactive. These regions contain magnetic fields that are generally weaker than those found in more active areas of the Sun. Their subtle structures are difficult to measure, especially with telescopes on the ground, where turbulence in Earth's atmosphere can blur fine details.
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