What is Electromagnetic energy?

Electromagnetic energy is waves of energy that ripple through the space around us, through us and all across the universe. This electromagnetic energy propagated in waves span a broad spectrum from very long radio waves to very short gamma rays. The human eye can detect only a small bandwidth of this spectrum called visible light. A radio detects a different portion of the spectrum, and an x-ray machine uses yet another portion. Science, medical and other technology instruments use the full range of the electromagnetic spectrum for communications, cooking, medical diagnostics and to study the Earth and the universe beyond.

Stars produce energy and it arrives at earth in various wavelengths, including obviously infrared (heat) and light. The transmission of this energy is thought to all travel at the same speed across space, known as the speed of light. The energy travels in pulses or waves. The more energy in the waves, the faster is the reoccurrence of the pulsing waves, and the closer the waves are to each other across the continuum of space and time. Low energy waves travel at the same speed as high energy waves, but the frequency of their waves are slower and the waves are further apart.

A good way to visualize this is to think about how mechanical waves of energy like sound travel through matter. A bass makes very low frequency sound waves in the air.

 

A flute vibrates the air particles at very high frequencies.

 

Yet it takes the same time for the vibrations emitted from both instruments to reach your ears. Sound waves, like waves in the sea, only conduct through a medium with matter like water or air. Watch below as the red compressor, as in an audio speaker compresses the particles. They bunch up and sort of bump into the particles in front of them, and after transferring their energy to the particles in front of them, they return to their same relative position, while the energy is transferred along in waves.

Higher frequency vibrations travel through space without air, in a vacuum. In fact, most higher frequency energy waves are actually blocked by our atmosphere. If the high energy waves coming through space was not filtered by our atmosphere, the energy would interfere with the molecular structure of our bodies and life would not be sustainable on earth. You can learn more about earth’s atmosphere here.

As energy is transmitted across space, magnetic waves are propagated also, and these magnetic waves pulse in coordination with the modulation of the light or other frequencies. The science of energy and magnetism is called Physics. How energy and magnetic waves travel through the vacuum of space is not understood, but is hotly debated by scientists and mathematicians. It’s fascinating to find and explore the fringe of what human science understands.

For the next article on the bandwidths of the electromagnetic spectrum, see here.

To download a very nice .pdf ebook developed by NASA, with great graphics, click Tour of the Electromagnetic Spectrum (7MB).

To review the information regarding how we hear, click here. To review the information regarding how we see, click here.