The unprecedented auroras that recently wowed millions of people across the globe were some of the most intense light shows our planet has seen for half a millennium, NASA has revealed. The dancing lights, which may have reached the equator, were triggered by Earth's most powerful geomagnetic storm in more than two decades.
Between May 10 and May 12, our planet experienced a major geomagnetic disturbance after at least five solar storms slammed into Earth back-to-back, temporarily weakening the magnetosphere. The solar storms, known as coronal mass ejections (CMEs), were launched by solar flares from the gigantic sunspot AR3664, which was more than 15 times wider than Earth at the time — the biggest dark patch to appear on the sun for a decade. Several of these solar flares reached "X-class" status — the most powerful type of surface explosion the sun can produce.
