Scientists have finally solved an 83-year-old solar mystery, discovering why the Sun's outer atmosphere, called the corona, is millions of degrees hotter than its surface. Researchers found direct evidence of small, twisting magnetic waves, known as torsional Alfvén waves, powering this extreme heat. The breakthrough came using the world's most powerful solar telescope, the Daniel K. Inouye Solar Telescope in Hawaii. ^{[1][2][3][4][5][6]} ### Long-Standing Solar Puzzle The Sun's visible surface, the photosphere, measures around 5,500 degrees Celsius (10,000 degrees Fahrenheit). However, the corona, which is the Sun's outermost layer, can reach temperatures exceeding 1 million degrees Celsius (1.6 million degrees Celsius or 2 million degrees Celsius, and up to 3.5 million degrees Fahrenheit).^{[1][7][8][3][4][9][5][6][10][11][12]} This temperature reversal defied basic physics for decades. Scientists have been searching for an explanation since the 1940s. ^{[1][2][3][4][5][6][13][12][14]} Professor Richard Morton from Northumbria University led the research team. Their findings, published in Nature Astronomy, provide the first direct observation of these elusive waves. ^{[1][2][7][8][3][4]}"This discovery ends a protracted search for these waves that has its origins in the 1940s," Professor Morton said. "We've finally been able to directly observe these torsional motions twisting the magnetic field lines back and forth in the corona." ^[1][7] ### Advanced Telescope Reveals Hidden Waves The Daniel K. Inouye Solar Telescope, operated by the U.S. National Science Foundation, made the discovery possible. Its Cryogenic Near Infrared Spectropolarimeter (Cryo-NIRSP) instrument played a crucial role. ^{[1][2][7][8][3][15][4][5]}This advanced tool allowed scientists to track the movement of iron heated to 1.6 million degrees Celsius in the corona. ^{[1][7][8][3][15][9][5]} Professor Morton developed new analytical techniques to isolate the small, twisting Alfvén waves. These waves were previously hidden by larger, swaying motions of plasma in the corona. H^{[1][2][7][3][9]}annes Alfvén, a Nobel Prize winner, first predicted the existence of these magnetic disturbances in 1942. Th^{[1][2][3][4][5][6]}ese waves transmit energy through the Sun's plasma, the super-hot, electrically charged gas that makes up the star. #^{[1][7][3][4][6][11]}## Impact on Space Weather The discovery of these continually present, small twisting waves suggests they are the essential ingredient for heating the solar corona. They carry energy from the Sun's interior into its outer atmosphere. Th^{[1][8][3][15][4][9][16][6]}is research has significant implications for understanding not only how the Sun works but also for predicting space weather. T^{[1][7][8][15][4][17][16][6]}he superheated corona is the source of the solar wind, a constant stream of charged particles that fills our solar system. Th^{[1][15][4][9][16][6][10]}is solar wind carries magnetic disturbances that can disrupt satellite communications, GPS systems, and power grids on Earth. Un^{[1][7][8][15][4][17][16][6]}derstanding these waves helps scientists predict how space weather might affect technology. T^{[1][7][8][15][4][17][16][6]}his breakthrough validates theoretical models describing how Alfvén wave turbulence powers the solar atmosphere. Scientists expect this discovery to open new avenues for studying wave physics in the Sun's atmosphere and further investigations into how these waves propagate and dissipate their energy. ME^{[1][2][7][8][3][15][4][6]}TA_TITLE: Sun's 83-Year Coronal Heat Mystery Solved by Twisting Magnetic Waves