Every day, invisible magnetic explosions are happening around Earth, on the surface of the sun and across the universe. These explosions, known as magnetic reconnection, occur when magnetic field lines cross, releasing stored magnetic energy. Such explosions are a key way that clouds of charged particles—plasmas—are accelerated throughout the universe. In Earth’s magnetosphere—the giant magnetic bubble surrounding our planet—these magnetic reconnections can fling charged particles toward Earth, triggering auroras.