For thousands of years, the aurora borealis has fascinated those lucky enough to bear witness to its appearance. But the cause has never been fully proven.

Research led by the University of Iowa has pinpointed the source of the stunning display to electromagnetic waves generated during geomagnetic storms.

These waves, known as Alfvén waves, push electrons towards Earth which interact with particles in the atmosphere generating the famous Northern Lights.

More specifically, energised particles are released by the Sun which race towards Earth. Upon arrival these electrons precipitate along the planet’s magnetic field in the upper atmosphere. After reacting with oxygen and nitrogen the molecules begin to emit colourful light.

Past space missions have pointed to this theory with Alfven waves spotted travelling towards Earth directly above auroras.

Meanwhile, here on Earth, it does not matter what causes the auroras, we can simply enjoy their dazzling display.