Astronomers have captured the most detailed images of the sun's turbulent surface, revealing golden bands and swirling vortices that could finally explain why the sun's corona, its outer atmosphere, is millions of degrees hotter than its surface. The images, taken by the Inouye Solar Telescope in Hawaii, show features smaller than 20 kilometers (12 miles) across in a magnetically active region near a sunspot.
Unprecedented Resolution Reveals Tiny Structures
The Inouye Solar Telescope, operated by the US National Solar Observatory near the summit of Haleakalā volcano on Maui, has achieved the highest spatial resolution images of the solar surface ever acquired. Previous observations had revealed granular structures the size of France, with details as small as 30 kilometers, but these latest images are at the limit of the telescope's capability, showing features as small as 20 kilometers.
Dr. Friedrich Wöger, a senior scientist at the US National Solar Observatory, confirmed: "These are the highest spatial resolution images of the solar surface ever acquired." Dr. David Kuridze, an astronomer on the team, expressed astonishment: "My first reaction was: 'Wow, how can we see such tiny, fine-scale structures on the sun?' This is something we have never seen before in any solar observations."
Kelvin-Helmholtz Instabilities on the Sun
In the new images, small whirlpool-like structures have been identified as signatures of Kelvin-Helmholtz instabilities (KHIs). These occur when fast-moving plasma slides past slower-moving fluid, creating shear at the interface. This sets up disturbances that grow into spiraling vortices, resembling breaking waves. Scientists have observed KHIs in lakes, oceans, and cloud formations on Earth, as well as in the atmospheres of Jupiter and Saturn, but this is the first confirmed sighting on the sun. The findings are published in the journal Nature.
Implications for Solar Physics and Space Weather
These vortices are now considered a key mechanism in the sun's magnetic field dynamics. Solar flares, jets, and coronal mass ejections are powered by extreme, fluctuating magnetic fields, which can disrupt power grids, satellites, GPS, and communications on Earth. The magnetic fields are generated by the movement of hot, charged plasma, but the physics is not fully understood. Astronomers know that magnetic field lines can twist around each other like braided hair, creating tension that is suddenly released when the lines break. The swirling vortices may explain why the field lines become braided in the first place, and why the corona is heated to a few million degrees Celsius while the surface is only about 6,000 degrees Celsius.
"This could solve the biggest mystery of the last half a century for solar physics and astrophysics," said Kuridze. "When you have this instability in the system, it is very easy to cascade the energy into smaller scales. And at some point, it just dissipates as heat. This could make hot coronas, hot outer atmospheres of the sun and similar stars."
Significance of the Findings
The images provide a new understanding of the sun's behavior, with potential implications for predicting space weather and protecting Earth's technology. The discovery of KHIs on the sun also offers a new avenue for studying plasma physics in extreme environments. The research team continues to analyze the data, hoping to uncover more details about the processes that heat the corona and drive solar activity.
