Terahertz radiation or sub-millimeter radiation is a region of the spectrum from about 100GHz to 30 terahertz (THz) between microwaves and far infrared which can be regarded as belonging to either band. Until recently, the range was rarely studied and few sources existed for microwave energy in the so-called terahertz gap, but applications such as imaging and communications are now appearing. Scientists are also looking to apply terahertz technology in the armed forces, where high-frequency waves might be directed at enemy troops to incapacitate their electronic equipment. [15] Terahertz radiation is strongly absorbed by atmospheric gases, making this frequency range useless for long-distance communication. Abdo, A. A.; Allen, B.; Berley, D.; Blaufuss, E.; Casanova, S.; Chen, C.; Coyne, D. G.; Delay, R. S.; Dingus, B. L.; Ellsworth, R. W.; Fleysher, L.; Fleysher, R.; Gebauer, I.; Gonzalez, M. M.; Goodman, J. A.; Hays, E.; Hoffman, C. M.; Kolterman, B. E.; Kelley, L. A.; Lansdell, C. P.; Linnemann, J. T.; McEnery, J. E.; Mincer, A. I.; Moskalenko, I. V.; Nemethy, P.; Noyes, D.; Ryan, J. M.; Samuelson, F. W.; Saz Parkinson, P. M.; etal. (2007). "Discovery of TeV Gamma-Ray Emission from the Cygnus Region of the Galaxy". The Astrophysical Journal. 658 (1): L33–L36. arXiv: astro-ph/0611691. Bibcode: 2007ApJ...658L..33A. doi: 10.1086/513696. S2CID 17886934.

In 1800, William Herschel discovered infrared radiation. [2] He was studying the temperature of different colours by moving a thermometer through light split by a prism. He noticed that the highest temperature was beyond red. He theorized that this temperature change was due to "calorific rays", a type of light ray that could not be seen. The next year, Johann Ritter, working at the other end of the spectrum, noticed what he called "chemical rays" (invisible light rays that induced certain chemical reactions). These behaved similarly to visible violet light rays, but were beyond them in the spectrum. [3] They were later renamed ultraviolet radiation. See also: History of electromagnetic theory, History of radio, History of electrical engineering, and History of optics Near-infrared, from 120 THz to 400 THz (2,500–750nm). Physical processes that are relevant for this range are similar to those for visible light. The highest frequencies in this region can be detected directly by some types of photographic film, and by many types of solid state image sensors for infrared photography and videography. Next in frequency comes ultraviolet (UV). The wavelength of UV rays is shorter than the violet end of the visible spectrum but longer than the X-ray. She moans so much about having to edit, surely there can’t be that much involved? I saw someone’s comment the other day thanking Emma for daily vlogging because she knows how much work is involved in it! Trust me, Emma is doing this for her own benefit, she’s not doing anyone a favour!In 1895, Wilhelm Röntgen noticed a new type of radiation emitted during an experiment with an evacuated tube subjected to a high voltage. He called this radiation " x-rays" and found that they were able to travel through parts of the human body but were reflected or stopped by denser matter such as bones. Before long, many uses were found for this radiography. The types of electromagnetic radiation are broadly classified into the following classes (regions, bands or types): [1]

Sources: File:Light spectrum.svg [12] [13] [14]Table shows the lower limits for the specified class Main article: Microwaves Plot of Earth's atmospheric opacity to various wavelengths of electromagnetic radiation. This is the surface-to-space opacity, the atmosphere is transparent to longwave radio transmissions within the troposphere but opaque to space due to the ionosphere. Plot of atmospheric opacity for terrestrial to terrestrial transmission showing the molecules responsible for some of the resonances Energetic ejection of core electrons in heavy elements, Compton scattering (for all atomic numbers), excitation of atomic nuclei, including dissociation of nuclei If radiation having a frequency in the visible region of the EM spectrum reflects off an object, say, a bowl of fruit, and then strikes the eyes, this results in visual perception of the scene. The brain's visual system processes the multitude of reflected frequencies into different shades and hues, and through this insufficiently-understood psychophysical phenomenon, most people perceive a bowl of fruit. Davidson, Michael W. "Johann Wilhelm Ritter (1776–1810)". The Florida State University . Retrieved 5 March 2013. Ritter […] hypothesized that there must also be invisible radiation beyond the violet end of the spectrum and commenced experiments to confirm his speculation. He began working with silver chloride, a substance decomposed by light, measuring the speed at which different colours of light broke it down. […] Ritter […] demonstrated that the fastest rate of decomposition occurred with radiation that could not be seen, but that existed in a region beyond the violet. Ritter initially referred to the new type of radiation as chemical rays, but the title of ultraviolet radiation eventually became the preferred term.Creation of particle-antiparticle pairs. At very high energies a single photon can create a shower of high-energy particles and antiparticles upon interaction with matter. a b c d e Mehta, Akul (25 August 2011). "Introduction to the Electromagnetic Spectrum and Spectroscopy". Pharmaxchange.info . Retrieved 2011-11-08.

Electromagnetic radiation with a wavelength between 380 nm and 760nm (400–790 terahertz) is detected by the human eye and perceived as visible light. Other wavelengths, especially near infrared (longer than 760nm) and ultraviolet (shorter than 380nm) are also sometimes referred to as light, especially when the visibility to humans is not relevant. White light is a combination of lights of different wavelengths in the visible spectrum. Passing white light through a prism splits it up into the several colours of light observed in the visible spectrum between 400nm and 780nm. Exactly, Why have video's stating that doctors have said if they both lost weight it would help them conceive a baby, but make no effort in actually doing so. Emma maybe doing slimming world (I have no clue haven't watched her in the longest time!) but they have to be both at least 20/25 stone each. Their is nothing wrong at all with being over weight. I'm over weighted (Not as much as them but I am) but What annoys me is they're so desperate for a child and make videos about it, then why not do something to help improve the odds in their favour. L'Annunziata, Michael; Baradei, Mohammad (2003). Handbook of Radioactivity Analysis. Academic Press. p.58. ISBN 978-0-12-436603-9. See which provider came out on top in our survey of the best and worst walking holiday companies. A more sustainable travel company will have clear carbon-zero targets

For instance, Much Better Adventures sets aside 5% of its revenue to support reforestation and rewilding projects. Look past green appearances Innovative and I'm made of rubber so that anything you say is ricochetin' off of me and it'll glue to you and Companies should avoid absolute claims, such as ‘sustainable’ rather than ‘more sustainable’. If you spot this wording, be sceptical and look for evidence.

Also, is she not capable of having a friendship without Chris involved? She moaned so much about being lonely and having no local friends then as soon as she made a friend (that youpenga girl) they started dragging their husbands along. Youpenga is such a fangirl, it’s embarrassing. Advanced weapon systems using lethal Short-pulse terahertz radiation from high-intensity-laser-produced plasmas". India Daily. March 6, 2005. Archived from the original on 6 January 2010 . Retrieved 2010-09-27. Uses of Electromagnetic Waves | gcse-revision, physics, waves, uses-electromagnetic-waves | Revision World It covers electromagnetic waves with frequencies ranging from below one hertz to above 10 25 hertz, corresponding to wavelengths from thousands of kilometers down to a fraction of the size of an atomic nucleus. This range is divided into separate bands, and the electromagnetic waves within each band are called by different names; beginning at the low-frequency (long-wavelength) end of the spectrum these are: radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays at the high-frequency (short wavelength) end.Whenever electromagnetic waves travel in a medium with matter, their wavelength is decreased. Wavelengths of electromagnetic radiation, whatever medium they are traveling through, are usually quoted in terms of the vacuum wavelength, although this is not always explicitly stated. At most wavelengths, however, the information carried by electromagnetic radiation is not directly detected by human senses. Natural sources produce EM radiation across the spectrum, and technology can also manipulate a broad range of wavelengths. Optical fiber transmits light that, although not necessarily in the visible part of the spectrum (it is usually infrared), can carry information. The modulation is similar to that used with radio waves. At the middle range of UV, UV rays cannot ionize but can break chemical bonds, making molecules unusually reactive. Sunburn, for example, is caused by the disruptive effects of middle range UV radiation on skin cells, which is the main cause of skin cancer. UV rays in the middle range can irreparably damage the complex DNA molecules in the cells producing thymine dimers making it a very potent mutagen. The infrared part of the electromagnetic spectrum covers the range from roughly 300GHz to 400 THz (1mm – 750nm). It can be divided into three parts: [1]