Ultra

Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park.Ultra eventually became the standard designation among the western Allies for all such intelligence. The name arose because the intelligence thus obtained was considered more important than that designated by the highest British security classification then used (Most Secret) and so was regarded as being Ultra secret. Several other cryptonyms had been used for such intelligence. British intelligence first designated it Boniface—presumably to imply that it was the result of human intelligence. The U.S. used the codename Magic for its decrypts from Japanese sources.

Much of the German cipher traffic was encrypted on the Enigma machine. Used properly, the German military Enigma would have been virtually unbreakable; in practice, shortcomings in operation allowed it to be broken. The term "Ultra" has often been used almost synonymously with "Enigma decrypts". However, Ultra also encompassed decrypts of the German Lorenz SZ 40/42 machines that were used by the German High Command, and the Hagelin machine and other Italian and Japanese ciphers and codes such as PURPLE and JN-25.

Light

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum. The word usually refers to visible light, which is visible to the human eye and is responsible for the sense of sight. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), or 4.00 × 10⁻⁷ to 7.00 × 10⁻⁷ m, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths). This wavelength means a frequency range of roughly 430–750 terahertz (THz).

The main source of light on Earth is the Sun. Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the energy used by living things. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight. Some species of animals generate their own light, a process called bioluminescence. For example, fireflies use light to locate mates, and vampire squids use it to hide themselves from prey.

Travel

Travel is the movement of people between relatively distant geographical locations, and can involve travel by foot, bicycle, automobile, train, boat, airplane, or other means, with or without luggage, and can be one way or round trip. Travel can also include relatively short stays between successive movements.

Etymology

The origin of the word "travel" is most likely lost to history. The term "travel" may originate from the Old French word travail. According to the Merriam Webster dictionary, the first known use of the word travel was in the 14th century. It also states that the word comes from Middle English travailen, travelen (which means to torment, labor, strive, journey) and earlier from Old French travailler (which means to work strenuously, toil). In English we still occasionally use the words travail and travails, which mean struggle. According to Simon Winchester in his book The Best Travelers' Tales (2004), the words travel and travail both share an even more ancient root: a Roman instrument of torture called the tripalium (in Latin it means "three stakes", as in to impale). This link reflects the extreme difficulty of travel in ancient times. Also note the torturous connotation of the word "travailler." Today, travel may or may not be much easier depending upon the destination you choose (i.e., Mt. Everest, the Amazon rainforest), how you plan to get there (tour bus, cruise ship, or oxcart), and whether or not you decide to "rough it (see extreme tourism and adventure travel). "There's a big difference between simply being a tourist and being a true world traveler," notes travel writer Michael Kasum. This is, however, a contested distinction as academic work on the cultures and sociology of travel has noted.