This discovery could help NASA and other organizations protect astronauts, satellites, and technologies on the ground from the potentially harmful effects of space weather.
For years, scientists have struggled to accurately predict solar flares—powerful bursts of energy from the sun that can send charged particles hurtling through the solar system. Now, using data from NASA's Solar Dynamics Observatory (SDO), researchers have discovered flickering loops in the sun's atmosphere, the corona, that could serve as an early warning of an impending solar flare.
This discovery could help NASA and other organizations protect astronauts, satellites, and technologies on the ground from the potentially harmful effects of space weather.
Exploring coronal loops for clues
The research team, led by heliophysicist Emily Mason of Predictive Sciences Inc. in San Diego, California, focused on coronal loops—arc-shaped structures extending from the sun’s surface. These loops form in magnetically active regions, the same regions where solar flares occur.
The team examined coronal loops near fifty powerful solar flares, analyzing how their brightness in extreme UV light changed in the hours before an eruption compared to loops over non-eruption areas. Like flashing warning lights, the loops over erupting areas varied much more than those over non-eruption areas.
The four windows in this video show the changes in the brightness of coronal loops at four different wavelengths of extreme UV light (131, 171, 193, and 304 angstroms) before a solar flare in December 2011. The images were taken by SDO's Atmospheric Imaging Suite and processed to reveal the flashes in the coronal loops. Credit: NASA/Solar Dynamics Observatory/JHelioviewer/E. Mason
Inconsistent flashing: a crucial discovery
"We found that some of the extreme UV light above active regions flashes inconsistently for several hours before a solar flare," Mason explained. "The results are very important for understanding solar flares, and may improve our ability to predict hazardous space weather."
The results, published in the Astrophysical Journal Letters in December 2024 and presented on January 15, 2025, at a press conference during the 245th meeting of the American Astronomical Society, also suggest that the flicker peaks earlier in more powerful outbursts. However, the team says that further observations are needed to confirm this connection.
Other researchers have tried to predict solar flares by examining magnetic fields on the sun, or by looking for consistent trends in other features of coronal loops. But Mason and her colleagues believe that measuring changes in the brightness of coronal loops could provide more accurate warnings of flares than those methods—two to six hours in advance with an accuracy of 60 to 80 percent.
Accurate prediction of solar flares
“A lot of the forecasting methods that have been developed still predict the likelihood of eruptions in a given time period and not necessarily the exact timing,” said team member Seth Garland, of the Air Force Institute of Technology at Wright-Patterson Air Force Base in Ohio.
“The solar corona is a dynamic environment, and every solar flare is like a snowflake—every flare is unique,” said team member Kara Nijewski, a graduate student at the Air Force Institute of Technology and the paper’s lead author. “We find that looking for periods of ‘chaotic’ behavior in coronal loop emissions, rather than specific trends, provides a much more consistent measure, and there may also be a correlation to the intensity of the flare.”
From research to real-world applications
Scientists hope that their findings about coronal loops could eventually be used to help protect astronauts, spacecraft, power grids and other assets from the harmful radiation associated with solar flares. For example, an automated system could look for changes in the brightness of coronal loops in real-time images from SDO, and send out alerts.
"Previous studies by other researchers report interesting predictive metrics," said co-author Vadim Uritsky, of NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the Catholic University of Washington, D.C. "We can build on that and develop a well-tested, and ideally simpler, indicator that is ready to move from research to applications."
More of the topic in Hayadan:
