Glow-in-the-dark materials can help cities stay cooler and use less electricity — here's how they work

If a path was painted with paint that glows all night, light energy would decrease by 27%, a simulation report showed.John Coletti/Getty Images
Luminescent materials are used for emergency lighting and street markings around the world.
They help keep cities cool by re-emitting light that would otherwise be converted into heat. 
As these glow-in-the-dark materials are improved, they can be used for more energy efficient cities. 
Around the year 1603, Italian shoemaker and amateur alchem