Is blue light dangerous to your health? To your eyes? What is blue light?
We don't normally see "the color" of light. To most of us, light is not something we see, but is an element that allows us to see...and it's colorless. Scientists, however, describe light as part of the electromagnetic spectrum which includes visible light, xrays, gamma and radio waves. Blue light is part of the electromagnetic spectrum of "visible light."
Visible light is composed of the entire range of wavelengths of the electromagnetic spectrum which are visible to us.
White light, the type of light we use everyday (such as the sun), seems to be colorless, but is really composed of many wavelengths of light of various colors. Sir Isaac Newton discovered this when shining "colorless" sunlight through a prism thus separating the various wavelengths into its component colors.
An easy way to remember the various colors of white light is the mnemonic, "ROY G BIV": Red, Orange, Yellow, Green, Blue, Indigo and Violet.
The wavelenghts of the visible light range from 380 to 700 nm (nanometers). A nanometer equals a billionth of a meter. Violet light is the shortest wavelength whereas red light is the longest wavelength. Shorter wavelengths of light contain more energy compared to longer wavelengths.
As you can see in the graphic, blue light is part of the visible spectrum ranging 380-500 nm. Blue light can be further broken down to blue-violet light (380-450 nm) and blue-turquoise light (450-500 nm).
Essentially, about 1/3 of all visible light is blue light.
Blue light is everywhere.
Sources of blue light include the sun, digital TV screens, cell phone, tablets, computers, fluorescent and LED lights. A blue sky, but the way, derives its color from high-energy (short wave) blue light in the atmosphere. The blue light scatters more than other wavelengths as it bounces off air and water molecules in the atmosphere. Blue light really is everywhere.