The electromagnetic (EM) spectrum is the range of all types of EM radiation.It is a continuum of all electromagnetic waves arranged according to frequency and wavelength. The sun, earth, and other bodies radiate electromagnetic energy of varying wavelengths. Electromagnetic energy passes through space at the speed of light in the form of sinusoidal waves.The wavelength is the distance from wave-crest to wave-crest.
Light (or radiation) is made up of vibrating waves of electrical and magnetic fields. This is where the term electromagnetic radiation comes from. Electromagnetic radiation travels in waves which have different wavelengths, energies and frequencies.
When we look at the world around us we are seeing visible light waves (or visible radiation). However, there are many other forms of radiation that we cannot see with our eyes. These types include gamma rays, x-rays, ultraviolet, infrared, microwaves and radio waves.Light is a particular type of electromagnetic radiation that can be seen and sensed by the human eye, but this energy exists at a wide range of wavelengths. The micron is the basic unit for measuring the wavelength of electromagnetic waves. The spectrum of waves is divided into sections based on wavelength. The shortest waves are gamma rays, which have wavelengths of 10e-6 microns or less. The longest waves are radio waves, which have wavelengths of many kilometers. The range of visible consists of the narrow portion of the spectrum, from 0.4 microns (blue) to 0.7 microns (red).
The Earth's atmosphere stops most types of electromagnetic radiation from space from reaching Earth's surface. The above illustration shows how far into the atmosphere different parts of the EM spectrum can go before being absorbed. Only portions of radio and visible light reach the surface.Most electromagnetic radiation from space is unable to reach the surface of the Earth. Radio frequencies, visible light and some ultraviolet light makes it to sea level. Astronomers can observe some infrared wavelengths by putting telescopes on mountain tops. Balloon experiments can reach 35 km above the surface and can operate for months. Rocket flights can take instruments all the way above the Earth's atmosphere, but only for a few minutes before they fall back to Earth.
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Electromagnetic Spectrum - Introduction
Gamma Waves
X-Ray Waves
Ultraviolet Waves
Visible Light Waves
Infrared Waves
Microwaves
Radio Waves
X-Ray Waves
Ultraviolet Waves
Visible Light Waves
Infrared Waves
Microwaves
Radio Waves
