Des formes tourbillonnantes, comme des vortex, observées à la surface du soleil.

Astronomers have captured unprecedented images of swirling, vortex-like patterns on the sun’s surface, revealing phenomena previously unseen in such detail. These intricate formations, resembling the swirling skies of Van Gogh’s The Starry Night, were observed using the Daniel K. Inouye Solar Telescope located in Hawaii. The images, released on August 5, mark a breakthrough in solar observation, offering insights into the complex dynamics of the sun and its potential influence on Earth. The observations focused on the photosphere, the sun’s visible surface, which is just a thin layer, about 60 miles deep, compared to the sun’s vast diameter of approximately 865,000 miles. The images and accompanying time-lapse videos show continuous growth of whirls composed of superheated plasma. These whirls range in size from 12 miles to 100 miles in diameter, making them detectable even by the most advanced solar telescopes. The plasma reaches temperatures so extreme that electrons break free from atoms, forming a charged particle soup. The swirling patterns are identified as the first confirmed detection of Kelvin-Helmholtz instability (KHI) on the surface of a star. First described in the 19th century, KHI occurs when two layers of fluid or gas move at different speeds, causing the boundary between them to become unstable and generate wave-like vortices. On Earth, similar phenomena manifest as swirling clouds or waves under wind-driven conditions. However, on the sun, the interaction involves hot plasma, reaching temperatures of about 6,000 degrees Kelvin and 10,000 degrees Fahrenheit, moving within a magnetic field that facilitates the instability. Friedrich Wöger, a senior scientist at the National Solar Observatory, explained that the KHI process results in the creation of energy that can lead to sudden solar explosions. “The interface can become unstable and develop wave-like vortices that grow in size until they break apart,” he said. This process, akin to waves on a lake or ocean, is unique to the sun due to the extreme conditions of plasma and magnetic fields. The discovery has been hailed as a significant advancement in solar physics. Wöger referred to it as “a true game-changer,” noting that it provides a new framework for understanding how the sun energizes its atmosphere. David Kuridze, another co-author of the study, emphasized that the sun and similar stars are highly dynamic systems, with frequent explosive events driven by magnetic activity. Understanding how these events are triggered is a major challenge in modern solar research. The KHI phenomenon could offer explanations for the sun’s outer atmosphere, the corona, reaching temperatures far hotter than the surface. It may also shed light on how magnetic energy accumulates and moves across the solar surface. According to Kuridze, the constant twisting motions generated by KHI contribute to the buildup of energy necessary to trigger coronal mass ejections and solar flares. These events release massive amounts of gas and radiation into space, potentially disrupting satellite operations, GPS navigation, power grids, and global communication networks on Earth. Beyond scientific implications, the researchers expressed admiration for the aesthetic quality of the new close-up views of the sun. The images highlight the beauty of celestial mechanics, blending art and science in a striking visual representation of cosmic forces.