When you buy through links on our articles, Future and its syndication partners may earn a commission.The sun lashes out with a powerful solar flare. Scientists may now know how these outflows are generated. | Credit: ESA/NASA/SOHOA giant solar flare on our sun was powered by an avalanche of smaller magnetic disturbances, providing the clearest insight yet into how energy from our star is released in a torrent of high-energy ultraviolet light and X-rays. The discovery was made by the European Space Agency (ESA) Solar Orbiter mission, which is imaging the sun from closer than any spacecraft before it.Some solar flares can result in coronal mass ejections (CMEs) – huge plumes of plasma blown off the sun’s corona and into deep space. If their trajectory away from the sun intersects with Earth’s location, they can trigger geomagnetic storms that can damage satellites and power grids while disrupting communications, and dazzle us with colorful auroral lights.AdvertisementAdvertisementAdvertisementAdvertisementThe more we learn about how solar flares are triggered, the better prepared we can be to predict when a harmful flare and CME is about to occur. Solar Orbiter’s new observations are a major step towards being able to do this.”This is one of the most exciting results from Solar Orbiter so far,” Miho Janvier, who is the ESA co-Project Scientist on Solar Orbiter, said in a statement. “Solar Orbiter’s observations unveil the central engine of a flare and emphasize the crucial role of an avalanche-like magnetic energy release mechanism at work.”Getting to the bottom of solar flaresOn Sept. 30, 2024, Solar Orbiter came within 27 million miles (43.3 million kilometers) of the sun, when it witnessed the eruption of a medium-class solar flare. Thanks to four of Solar Orbiter’s instruments working in unison to observe the flare, scientists have, for the first time, seen how smaller magnetic instabilities can build up into a large flare, like an avalanche on a snowy mountainside originating from a relatively small disturbance.”We were really very lucky to witness the precursor events of this large flare in such beautiful detail,” research lead author Pradeep Chitta of the Max Planck Institute for Solar System Research, Germany, said. “We really were in the right place at the right time to catch the fine details of this flare.”AdvertisementAdvertisementAdvertisementAdvertisementSolar flares are the product of magnetic reconnection. This is when magnetic field lines on the sun, laced with high-energy plasma, become taut and snap, releasing huge amounts of energy before the field lines reconnect. The precise origins of solar flares, however, have been secretive. Are they a single powerful eruption, or an accumulation of smaller reconnection events? For the 30 September flare at least, Solar Orbiter found the answer.Starting with its Extreme Ultraviolet Imager (EUI), Solar Orbiter witnessed the generation of the flare over the course of 40 minutes. EUI detected changes in the magnetic environment of the sun’s corona local to the eruption point of the flare, capturing details as small as a few hundred kilometers on timescales of less than two seconds, which is the time covered in each image frame.The spacecraft saw an arching filament made from entwined magnetic fields carrying plasma and connected to a cross-shaped region of magnetic activity laced with more magnetic field lines. It watched as the region grew increasingly unstable, field lines snapping and reconnecting, releasing bursts of energy that appeared as bright points of light.A snapshot of the sun captured by Solar Orbiter mome …
