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Electromagnetic Spectrum

From radio waves to gamma rays โ€” see how the spectrum changes as wavelength shortens, mapped out in color.

โ“˜ Only the visible light band shows colors you can actually see. The colors used for the other bands (radio through infrared, and ultraviolet through gamma) are a conceptual aid to distinguish wavelengths that are invisible to the eye (infrared-family bands in red tones, ultraviolet and beyond in violet tones).
โ† Longer wavelength (radio)Shorter wavelength (gamma) โ†’

โ€ป Wavelengths differ by millions of times or more between bands, so segment widths are not to exact scale โ€” they're adjusted so every band stays visible. Treat this as a guide to relative order and rough scale only.

What is the electromagnetic spectrum?

Light is both a wave and a type of electromagnetic radiation. Electromagnetic waves are divided by wavelength (the distance between successive crests) into radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays โ€” and arranging these in order of wavelength gives the electromagnetic spectrum. Shorter wavelengths carry higher energy; longer wavelengths carry lower energy.

How exact are the boundaries between bands?

The wavelength ranges shown here follow commonly cited reference values (ISO 20473 for the infrared sub-bands, and standard optics references for UV/visible). That said, the finer boundaries of infrared (near/mid/far) and ultraviolet vary somewhat between fields and sources, so treat them as approximate rather than absolute.

Frequently Asked Questions

How do X-rays and gamma rays differ?

Their wavelength ranges can actually overlap. They're usually distinguished by how they're produced instead: X-rays generally come from electron transitions, while gamma rays come from atomic nucleus decay.

How does an infrared (thermal-imaging) camera work?

Every object emits infrared radiation (mostly far-infrared) based on its temperature. A thermal-imaging camera detects the intensity of that infrared radiation and visualizes the temperature distribution as color.

What kind of UV does sunscreen actually block?

Sunscreens are generally formulated to block both UVA and UVB. The SPF rating on a product mainly reflects UVB protection, while a "broad spectrum" or star/PA rating (used in some markets) indicates UVA protection.