Seen through a special telescope, the Sun looks like a bright blanket stitched with dark, winding threads. In reality, these are arches of cool gas floating above the scorching surface. Invisible magnetic lines hold them up like a framework. Sometimes the threads snap — and clouds of gas fly into space, capable of damaging satellites and power grids.

Marking these threads by hand is incredibly difficult. Scientists have created a program, akin to an automated embroidery machine. First it scans the whole picture, then refines the edges of each thread — as if smoothing them with an iron to make the outline crisp. A second algorithm, without knowing the number of threads in advance, stitches fragments into continuous lines.

Thanks to this, the new tool finds threads in old photographs from various telescopes. Now we can review decades of archives and understand where threads snapped more often. And this is a first step toward predicting dangerous solar flares and protecting equipment on Earth.