Ultraviolet

Ultraviolet (UV) light is an electromagnetic radiation with a wavelength from 400 nm (750 THz) to 10 nm (30 PHz), shorter than that of visible light but longer than X-rays. Though usually invisible, under some conditions children and young adults can see ultraviolet down to wavelengths of about 310 nm, and people with aphakia (missing lens) can also see some UV wavelengths. Near-UV is visible to some insects and birds.

UV radiation is present in sunlight, and also produced by electric arcs and specialized lights such as mercury-vapor lamps, tanning lamps, and black lights. Although lacking the energy to ionize atoms, long-wavelength ultraviolet radiation can cause chemical reactions, and causes many substances to glow or fluoresce. Consequently, biological effects of UV are greater than simple heating effects, and many practical applications of UV radiation derive from its interactions with organic molecules.

Suntan, freckling and sunburn are familiar effects of over-exposure, along with higher risk of skin cancer. Living things on dry land would be severely damaged by ultraviolet radiation from the sun if most of it were not filtered out by the Earth's atmosphere, particularly the ozone layer. More-energetic, shorter-wavelength "extreme" UV below 121 nm ionizes air so strongly that it is absorbed before it reaches the ground. Ultraviolet is also responsible for the formation of bone-strengthening vitamin D in most land vertebrates, including humans. The UV spectrum thus has effects both beneficial and harmful to human health.

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.

Light Yagami

Light Yagami (Japanese: 夜神 月(ライト), Hepburn: Yagami Raito) is a fictional character and the protagonist of the manga series Death Note, created by Tsugumi Ohba and Takeshi Obata. He is a bored young genius who finds the Death Note dropped by the Shinigami Ryuk by pure chance. Using the notebook, which allows its owner to kill anyone simply by knowing their name and face, Light becomes a mass-murderer known as Kira (キラ) in an attempt to create and rule a utopia cleansed of criminals, with him at the helm as a "god".

In the anime adaptation, he is voiced by Mamoru Miyano in the Japanese version and by Brad Swaile in the English; in the live-action film series, he is portrayed by Tatsuya Fujiwara, in the TV drama, he is portrayed by Masataka Kubota and, in the American film, he will be portrayed by Nat Wolff.

Creation and conception

Tsugumi Ohba, the story writer of Death Note, said that his editor suggested the family name "Yagami" for Light. Ohba said that he did not feel "too concerned" about the meaning of the name (the Kanji for "Yagami" are "night" and "god"); he said that after he created the final scene in the manga he "liked" that the final scene created "deeper significance" in the name, of Kira worshippers worshipping him at night under the light of the moon.

Light (novel)

Light is a science fiction novel by M. John Harrison published in 2002. It received the James Tiptree, Jr. Award and a BSFA nomination in 2002, and was shortlisted for the Arthur C. Clarke Award in 2003.

Overview

The book centres on the lives of three individuals — the physicist (and serial killer) Michael Kearney, on the verge of a breakthrough in theoretical physics sometime in 1999; Seria Mau Genlicher, the cybernetically-altered female pilot of a "K-ship", and the ex-space pilot and adventurer Ed Chianese. Seria Mau and Ed's stories take place in the year 2400 AD.

The lives of these three individuals are linked in many ways, though most tangibly by the presence of a mysterious creature called The Shrander, who appears in many guises to all three characters throughout the novel (with anagrammatic names of Sandra Shen and Dr. Haends). They are also linked by the Kefahuchi Tract, a space-time anomaly described as "a singularity without an event horizon", an object of awe and wonder that has been the ruin of many civilisations attempting to decode its mysteries.