image by: Green Bank Observatory

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Catching Waves

When and how did scientists come to recognize the existence of invisible light? What are its properties and practical applications? Which types are harmful or beneficial to our health? Veteran astronomy author Bob Berman surveys the historical and scientific aspects of unseen radiation in “Zapped: From Infrared to X-rays, the Curious History of Invisible Light,” examining each of the non-visible forms of electromagnetic energy in turn, from radio waves at one end of the wavelength spectrum to gamma rays at the other. Mr. Berman begins with a chronological digest of theories about light and seeing. “Until the eighteenth century,” he writes, “no one had the faintest idea that there might be such…

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Articles of Interest

A Self-Guided Tour of the Electromagnetic Spectrum

To us, light is the most obvious form of electromagnetic radiation, yet it makes up just a small portion of the electromagnetic spectrum. We invite you to take this self-guided tour, which covers the spectrum from radio waves to gamma rays.

Electromagnetic Radiation & Electromagnetic Spectrum

The word light usually makes one think of the colors of the rainbow or light from the Sun or a lamp. This light, however, is only one type of electromagnetic radiation. Electromagnetic radiation comes in a range of energies, known as the electromagnetic spectrum. The spectrum consists of radiation such as gamma rays, x-rays, ultraviolet, visible, infrared and radio.

Electromagnetic spectrum

The electromagnetic spectrum is a range of wavelengths of electromagnetic radiation. From long to short wavelength, the EM spectrum includes radio waves, microwaves, infrared, visible light, ultraviolet, x-rays and gamma rays. Energy is propagated through space in the form of electromagnetic (EM) waves, which are composed of oscillating electric and magnetic fields. EM waves do not require a substance (like air or water) to travel through, meaning that — unlike sound — they can travel through empty space.

Electromagnetic Spectrum: From XUV to Microwaves

Welcome to the intricate and expansive universe of the electromagnetic spectrum, a fundamental yet often overlooked cornerstone of modern science and technology. Spanning from the extreme ultraviolet (XUV) rays, barely perceptible yet instrumental in shaping the very fabric of our cosmos, to the familiar yet complex microwaves and millimeter waves, which silently orchestrate much of our daily digital dance.

Explainer: what is the electromagnetic spectrum?

Visible light forms part of the electromagnetic spectrum. So do emissions from TV and radio transmitters, mobile phones and the energy inside microwave ovens. The X-rays used in diagnostic imaging and the materials used in advanced positron emission tomography scanners (PET) also form part of this amazing range of radiations which share some features in common. Why electromagnetic? As the name implies, they have electric and magnetic fields associated with them. Although it is a bit complicated to demonstrate these fields in the case of light and X-rays, it is quite easy to picture with radio-waves.

Introduction to the Electromagnetic Spectrum

Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. The human eye can only detect only a small portion of this spectrum called visible light. A radio detects a different portion of the spectrum, and an x-ray machine uses yet another portion. NASA's scientific instruments use the full range of the electromagnetic spectrum to study the Earth, the solar system, and the universe beyond. When you tune your radio, watch TV, send a text message, or pop popcorn in a microwave oven, you are using electromagnetic energy. You depend on this energy every hour of every day. Without it, the world you know could not exist.

More than meets the eye: the electromagnetic spectrum

We learn about the world around us via our senses. Our eyes play a major role, because light carries a great deal of information about its source and about the objects that either reflect or absorb it. Like most animals, humans have a visual system that collects luminous signals and relays them to the brain. Our eyes, however, are only sensitive to a very small portion of the spectrum of light – we are blind to anything but what we call ‘visible’ light.

Radio Waves to Gamma-rays

The entire electromagnetic spectrum is presented from the longest wavelengths of light (radio waves) to the shortest wavelengths of light (gamma-rays)...

The Electromagnetic Spectrum

The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation. The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays and gamma-rays.

You’ve probably never heard of terahertz waves, but they could change your life

Between the beams of visible light and the blips of radio static, there lies a dead zone where our technology isn’t effective. It’s called the terahertz gap. For decades now, no one’s succeeded in building a consumer device that can transmit terahertz waves.

Resources

BBC

There are lots of examples of electromagnetic waves around us, including light waves, radio waves and infrared radiation. These electromagnetic waves are caused by vibrating electric and magnetic fields and they are transverse waves , because the vibrations of these fields are at right angles to the direction the wave travels. Electromagnetic waves travel at an extremely high speed: the speed of light. The speed of light in a vacuum is around 300,000,000 metres per second. At that speed, light can travel 7.5 times around Earth in just one second.