Scientists used the world’s largest solar telescope to capture incredibly detailed images of the Sun’s surface, revealing ultra-fine magnetic stripes rippling across the star and magnetic fields that resemble fluttering curtains, which modify light.
The Daniel K. Inouye Solar Telescope stands tall at 13 feet (4 meters) atop a volcano in Maui, Hawaii, staring at our host star with great intensity. Using the telescope’s unique capabilities, a team led by scientists from the National Science Foundation (NSF) observed ultra-narrow bright and dark stripes on the solar photosphere at an unprecedented level of detail. The recent observations, published in The Astrophysical Journal Letters, offer new insight into how the Sun’s magnetic fields shape the dynamics at its surface and affects space weather.
The stripes, called striations, ripple across the walls of solar granules—convection cells in the Sun’s photosphere where hot gas rises from inside the star to reach the surface. They’re around 12 miles wide (20 kilometers), roughly the length of Manhattan, which is tiny compared to the monstrous size of the Sun.
The striations are the result of curtain-like sheets of magnetic fields that ripple and shift across the surface of the Sun. As light from the granule walls passes through these fields, it appears to flutter and alternate between brightness and darkness. This variation is an indication of the underlying magnetic field, which appears dark when it’s weaker and bright when it’s relatively stronger. “These striations are the fingerprints of fine-scale magnetic field variations,” David Kuridze, a scientist at the National Solar Observatory and the study’s lead author, said in a statement.
The team behind the study used the Inouye telescope’s Visible Broadband Imager instrument, which operates in a specific range of visible light, called the G-band, that highlights areas with strong magnetic activity. Scientists then compared the telescope’s images with simulations that recreate the physics of the Sun’s surface, finding them to be in agreement.
“Magnetism is a fundamental phenomenon in the universe, and similar magnetically induced stripes have also been observed in more distant astrophysical objects, such as molecular clouds,” Han Uitenbroek, NSO scientist and co-author of the study, said in a statement. “Inouye’s high resolution, in combination with simulations, allows us to better characterize the behavior of magnetic fields in a broad astrophysical context.”
Located approximately 93 million miles (149 million kilometers) from Earth, the Sun has been holding our solar system together with its gravity for nearly five billion years, and yet there is still so much we don’t know about our host star. By studying the magnetic architecture of the solar surface, scientists are hoping to understand the physics behind solar eruptions, flares, and coronal mass ejections so that they can better predict space weather.
The Sun is currently at solar maximum, a period of heightened activity in its 11-year cycle which is marked by intense flareups that can sometimes be directed toward Earth. On May 10, 2024, a G5 magnetic storm—classified as extreme—hit Earth as a result of large expulsions of plasma from the Sun’s corona. The G5 storm, the largest in more than 20 years, caused some deleterious effects on Earth’s power grid and some spectacular auroras seen across much of the globe. The storm also increased atmospheric density in low Earth orbit by up to an order of magnitude, which in turn caused atmospheric drag that affected satellites.
