The northern lights or aurora borealis are caused by high-energy particle streams from the sun, interacting with atoms and molecules in the earth's ionosphere. These high energy particles from the sun can also be dangerous for our technological infrastructure, affecting communications satellites, which can result in drop-outs in radio communications. They can also have a deleterious affect on astronauts, spacecraft electronics and cause surges in power networks on the ground that can even lead to blackouts. EISCAT Scientific Association operates four radar antenna sites, located above the Arctic Circle, to enable research on the ionosphere and the upper atmosphere. RAZOR’s Reya El-Salahi investigates why the beautiful northern lights can be a sign of problems for technology and visits EISCAT 3D, a next generation radar array which will look at large parts of the sky, providing 3D visualisations.