Light Pollution

Mount Teide (Spanish: Pico del Teide, IPA: [ˈpiko ðel ˈteiðe], "Teide Peak") is a volcano on Tenerife in the Canary Islands. Its 3,718-metre (12,198 ft)-high summit is the highest point in Spain, the highest point above sea level in the islands of the Atlantic, and it is the third highest volcano in the world measured from its base on the ocean floor, after Mauna Loa and Mauna Kea located in Hawaii. For this reason, Tenerife is the tenth highest island worldwide. It remains active, with its most recent eruption occurring in 1909 from the El Chinyero vent on the north western Santiago rift. The United Nations Committee for Disaster Mitigation designated Teide as a Decade Volcano, because of its history of destructive eruptions and its proximity to several large towns, of which the closest are Garachico, Icod de los Vinos and Puerto de la Cruz. Teide together with its neighbour Pico Viejo and Montaña Blanca form the Central Volcanic Complex.

The volcano and its surroundings comprise the Teide National Park. The park has an area of 18,900 hectares (73 sq mi) and was named a World Heritage Site by UNESCO on June 29, 2007. Is also one of the most visited National Parks in the world, with a total of 2.8 million visitors, according to the Instituto Canario de Estadística (ISTAC).

A volcano is an opening, or rupture, in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface.

Volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are usually not created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust in the interiors of plates, e.g., in the East African Rift, the Wells Gray-Clearwater volcanic field and the Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "Plate hypothesis" volcanism. Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core-mantle boundary, 3,000 km deep in the Earth.

Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.

The International Dark-Sky Association (IDA) defines light pollution as:

This approach confuses the cause and the result, however. Pollution is the adding-of/added light itself, in analogy to added sound, carbon dioxide, etc. Adverse consequences are multiple; some of them may be not known yet. Scientific definitions thus include the following:

The first three of the above four scientific definitions describe the state of the environment. The fourth (and newest) one describes the process of polluting by light.

Light pollution obscures the stars in the night sky for city dwellers, interferes with astronomical observatories, and, like any other form of pollution, disrupts ecosystems and has adverse health effects. Light pollution can be divided into two main types: (1) annoying light that intrudes on an otherwise natural or low-light setting and (2) excessive light (generally indoors) that leads to discomfort and adverse health effects. Since the early 1980s, a global dark-sky movement has emerged, with concerned people campaigning to reduce the amount of light pollution.

Light pollution is a side effect of industrial civilization. Its sources include building exterior and interior lighting, advertising, commercial properties, offices, factories, streetlights, and illuminated sporting venues. It is most severe in highly industrialized, densely populated areas of North America, Europe, and Japan and in major cities in the Middle East and North Africa like Tehran and Cairo, but even relatively small amounts of light can be noticed and create problems. Like other forms of pollution (such as air, water, and noise pollution) light pollution causes damage to the environment.

This is a list of active and extinct volcanoes in Spain.