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Regarding the future applications of terahertz technology, I thought we already knew the entire electromagnetic spectrum. In fact we do not, terahertz lies between microwaves and infrared radiation. The future applications of this is astonishing. For example, faster communications and next generation scanning and imaging technologies. The TSA will pretty much be out of a job, because T-Ray(terahertz) scanners will automatically detect chemical weapons and bombs. I know this because they leave a trace on the terahertz spectrum. The downside with communications is terahertz is absorbed easily by the Earth's atmosphere, so the communications cannot be too high in the sky. What I am asking is, are there any other frequencies on the electromagnetic spectrum we might discover? I was taught in school, that there are radio waves, microwaves, infrared, visible, ultra violent, x-rays, and gamma rays. Now the books have to be rewritten because of the existence of terahertz or t-rays. Remember it lies right between microwaves and infrared radiation. Another question is what about sound? So far there is infra sound, sound, and ultrasound. Do you think in the future we will discover other types of sound? Sorry for the length of my question, as you can see I know a lot about science and technology.

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We did know of all the spectrum ever since Maxwell's equations were discovered. But only relatively recently have we become able to generate terahertz radiation efficiently, that's why only now talks are about its applications. –  Ruslan Jan 23 at 8:13
"Fascinating, captain: a new form of energy!" <-- As all other responses indicate, certainly not. –  Carl Witthoft Jan 23 at 12:43

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It is just a matter of semantics, what one calls the slices of the spectra The spectra exist and were known since the nineteenth century. If one is able to concentrate on a particular scale and christens it with a new name, there is no problem.

em spectrum

A diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths

The classification depended on the type of detection.

Particularly for sound, which is what the ear hears, and the other two , ultra , which means over and infra below, are just what the ear hears and above or below.

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