New Images Reveal Sun’s Surface in Finest Detail Yet
Scientists have captured the highest-resolution images ever taken of the sun’s surface, revealing never-before-seen whirlpool-like structures that could help explain some of the most enduring mysteries of solar physics. The groundbreaking observations, made using the National Science Foundation’s Daniel K. Inouye Solar Telescope in Hawaii, were published Wednesday in the journal Nature.
The images show the sun’s visible surface, or photosphere, at a spatial resolution of approximately 19 kilometers — the diffraction limit of the world’s most powerful solar telescope. At this unprecedented level of detail, researchers identified swirling, vortex-like patterns of superheated plasma that represent the first confirmed detection of a phenomenon called Kelvin-Helmholtz instability (KHI) on the surface of a star.
“My first reaction was: ‘Wow, how can we see such tiny, fine-scale structures on the sun?’” said Dr. David Kuridze, an astronomer at the National Solar Observatory and co-lead author of the study. “This is something we have never seen before in any solar observations.”
A Happy Accident
The discovery was something of a happy accident. The images were originally captured on April 14, 2025, not to hunt for KHI structures, but to fine-tune and test the limits of the telescope’s capabilities. Using a high-speed camera called FastCam — a collaborative effort between the National Solar Observatory and the Max Planck Institute for Solar System Research — the team snapped 740 grayscale frames per second with an exposure time of 1/10,000 second per frame.
“The acquisition of the data used in the study itself actually did not take much longer than five minutes,” said Dr. Friedrich Wöger, senior scientist at the National Solar Observatory and co-lead author. “We’ve seen the Sun’s large-scale events, but we’ve been missing some of the small-scale physics that power these events — the tiny engines that drive solar activity. The Inouye [telescope] gives us a clearer view of these processes, and KHI may be one of these engines.”
Understanding Kelvin-Helmholtz Instability
Kelvin-Helmholtz instability is a well-known fluid dynamics phenomenon first described in the 19th century by Lord Kelvin and Hermann von Helmholtz. It occurs when two parallel streams of fluids or gases interact while moving at different velocities, creating shear at the interface that develops into wave-like vortices. On Earth, it produces the distinctive billowing cloud formations seen in the sky and helps explain how ripples on the ocean grow into powerful waves.
On the sun, the phenomenon occurs when magnetized plasma moves past non-magnetized plasma at different speeds. The observed vortices range from about 12 miles (19 km) to roughly 100 miles (170 km) in diameter — large on a human scale but tiny on the scale of a stellar surface.
“The interface can become unstable and develop wave-like vortices that grow in size until they break apart, not unlike waves out on a lake or out on the ocean in windy conditions,” Wöger said. “The difference from the waves and clouds we know here on Earth is that the two interacting fluids are hot plasma — about 6,000 degrees Kelvin and 10,000 degrees Fahrenheit — moving within a magnetic field that helps create the conditions for the instability to develop.”
While KHI has been observed in the atmospheres of Jupiter and Saturn, and even in the sun’s corona, this marks the first time it has been confirmed on the photosphere — the visible surface of a star. The findings were validated using state-of-the-art MURaM numerical simulations, which reproduced the observed structures with remarkable fidelity.
Solving the Corona Heating Mystery
The discovery could help resolve one of the biggest unsolved problems in solar physics: why the sun’s corona — its outer atmosphere — reaches temperatures of 1 to 2 million degrees Celsius while the surface is only about 5,500 degrees Celsius. This temperature inversion has puzzled scientists for half a century.
By twisting the solar magnetic field, KHI creates energy that can build up and eventually be released as explosive events. “These twisting motions are creating magnetic energy, which can build up to produce those large-scale explosions,” Kuridze told BBC News.
“This could solve this biggest mystery of the last half a century for solar physics and astrophysics,” Kuridze said. “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 a heat. This could make hot coronas, hot outer atmospheres of the sun and similar stars.”
The swirling vortices may also explain how magnetic field lines become braided in the first place — a process that leads to the sudden release of energy in solar flares and coronal mass ejections. As The Guardian reported, astronomers know that magnetic field lines can twist around each other like braided hair, creating tension that is suddenly released when the tangled lines break. What has been less clear is what starts the process — and the swirling vortices are now a key culprit.
Implications for Space Weather
The findings have practical implications for predicting space weather on Earth. Coronal mass ejections — huge bubbles of gas threaded with magnetic field lines expelled from the sun — and solar flares can disrupt GPS communications, power grids, satellites, and global communications when they strike Earth. They also produce colorful auroras.
“The Sun is the source of that energy and of all of that space weather,” explained Dr. David Boboltz from the US National Solar Observatory. “To figure out and eventually predict space weather, we want to understand the physics of the Sun, all the way down to the smallest scales.”
Understanding KHI on the sun’s surface could help scientists better predict these disruptive events. As Science News noted, the instability occurs everywhere at the boundaries of solar magnetic elements, making it a ubiquitous process that drives much of the sun’s activity.
A New Era of Solar Observation
The Daniel K. Inouye Solar Telescope, with its 4-meter aperture, is the largest solar telescope ever built. Located near the summit of the Haleakalā volcano on the island of Maui, it can reveal features three times smaller than anything previously visible on the sun. Its first light images, released in January 2020, showed granular structures each about the size of France — but the latest observations push far beyond that.
“We’ve never observed the Sun at that resolution,” said Michael Wheatland, an astrophysicist at the University of Sydney who was not involved in the research, as reported by ABC Australia. “In this amazing detail, we see all of this really interesting fundamental physics happening.”
Hannah Schunker, an astrophysicist at the University of Newcastle who also was not involved, echoed that sentiment: “The Sun is like an astrophysical laboratory. These very small-scale changes that are happening on the surface of the Sun, they are responsible for all the larger scale things happening in the atmosphere, and we’ve never been able to see them before.”
Beyond the science, the researchers acknowledged the sheer beauty of the new images. “Maybe ‘magnificent’ comes closest to describing the aesthetics in the images for us,” Wöger said. Kuridze drew a parallel to art: “Interestingly, artists have long captured this fluid dynamic intuition in their work. A famous example is Van Gogh’s ‘The Starry Night,’ where the sky’s vortex structures closely resemble turbulent KHI structures.”
As scientists continue to analyze the data and plan future observations with the Inouye telescope, the discovery opens a new window into understanding our closest star — and the fundamental physics that govern it. As Leon Ofman, an astrophysicist at the Catholic University of America who was not involved in the study, told Scientific American: “We are now beginning to understand that we need to study this process in order to understand all the stages of the transfer of energy from the interior [of the sun], going to the surface and then affecting us on Earth and beyond.”