Q&A
THE EXPLAINER BLUE LIGHT
GETTY IMAGES X4, ALAMY
WHAT IS BLUE LIGHT?
The Sun bathes us daily in light, which is one of many types of electromagnetic radiation, along with radio waves, microwaves and gamma rays. We can’t see the vast majority of these energy waves flowing through space, but we can measure them. The light that human eyes can see, as it bounces off objects, has wavelengths of between 380 and 700 nanometres. Within this spectrum, running from violet to red, blue light vibrates with almost the lowest wavelength (400 to 450nm) but almost the highest energy.
There couldn’t be anything more ordinary than blue light. It’s the reason the sky looks blue – because it bounces off the molecules in the Earth’s atmosphere more readily than the rest of the visible light spectrum. Most of us weren’t particularly aware of blue light until manufacturers discovered the quality with which blue-light-heavy LED technology can produce light and colour, with supreme efficiency in both power and size – ideal for electronic lighting and smart devices. Now that these devices have become our interface with the world, many of us stare at blue light all day, and long after the Sun goes down.